Author: "Deborah N. Huntzinger" / Topic: 0105 earth and related environmental sciences - Searchworks@Jio Institute Digital Library Search Results

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29 results on '"Deborah N. Huntzinger"'

1. Linking global terrestrial CO2 fluxes and environmental drivers: inferences from the Orbiting Carbon Observatory 2 satellite and terrestrial biospheric models

Author: Atul K. Jain, Joe R. Melton, Etsushi Kato, Deborah N. Huntzinger, Junjie Liu, Vladislav Bastrikov, Zichong Chen, Patrick C. McGuire, Sebastian Lienert, Vanessa Haverd, Pierre Friedlingstein, Scot M. Miller, Daven K. Henze, Julia E. M. S. Nabel, Emilie Joetzjer, Benjamin Poulter, Daniel S. Goll, Danica Lombardozzi, Sönke Zaehle, Kelley C. Wells, Hanqin Tian, Andy Wiltshire, and Stephen Sitch
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Biome, Biosphere, Contrast (statistics), 15. Life on land, Atmospheric sciences, 01 natural sciences, Carbon cycle, 13. Climate action, Photosynthetically active radiation, Observatory, Environmental science, Satellite, Precipitation, 0105 earth and related environmental sciences
Abstract: Observations from the Orbiting Carbon Observatory 2 (OCO-2) satellite have been used to estimate CO2 fluxes in many regions of the globe and provide new insight into the global carbon cycle. The objective of this study is to infer the relationships between patterns in OCO-2 observations and environmental drivers (e.g., temperature, precipitation) and therefore inform a process understanding of carbon fluxes using OCO-2. We use a multiple regression and inverse model, and the regression coefficients quantify the relationships between observations from OCO-2 and environmental driver datasets within individual years for 2015–2018 and within seven global biomes. We subsequently compare these inferences to the relationships estimated from 15 terrestrial biosphere models (TBMs) that participated in the TRENDY model inter-comparison. Using OCO-2, we are able to quantify only a limited number of relationships between patterns in atmospheric CO2 observations and patterns in environmental driver datasets (i.e., 10 out of the 42 relationships examined). We further find that the ensemble of TBMs exhibits a large spread in the relationships with these key environmental driver datasets. The largest uncertainty in the models is in the relationship with precipitation, particularly in the tropics, with smaller uncertainties for temperature and photosynthetically active radiation (PAR). Using observations from OCO-2, we find that precipitation is associated with increased CO2 uptake in all tropical biomes, a result that agrees with half of the TBMs. By contrast, the relationships that we infer from OCO-2 for temperature and PAR are similar to the ensemble mean of the TBMs, though the results differ from many individual TBMs. These results point to the limitations of current space-based observations for inferring environmental relationships but also indicate the potential to help inform key relationships that are very uncertain in state-of-the-art TBMs.
Published: 2021
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2. Five years of variability in the global carbon cycle: comparing an estimate from the Orbiting Carbon Observatory-2 and process-based models

Author: Daniel S. Goll, Xuhui Wang, Vanessa Haverd, Stephen Sitch, Scot M. Miller, Julia E. M. S. Nabel, Sönke Zaehle, Emilie Joetzjer, Benjamin Poulter, Sebastian Lienert, Andy Wiltshire, Vladislav Bastrikov, Danica Lombardozzi, Julia Pongratz, Atul K. Jain, Shilong Piao, Joe R. Melton, Hanqin Tian, Etsushi Kato, Deborah N. Huntzinger, Zichong Chen, Junjie Liu, Peter Anthoni, Pierre Friedlingstein, Patrick C. McGuire, A. Arneth, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)
Subjects: Biosphere model, 010504 meteorology & atmospheric sciences, 530 Physics, Biome, OCO-2 satellite, Magnitude (mathematics), Tropical and subtropical grasslands, savannas, and shrublands, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Carbon cycle, inter-annual variability, 550 Earth sciences & geology, carbon cycle, ddc:550, climate-carbon relationships, Precipitation, 0105 earth and related environmental sciences, General Environmental Science, Renewable Energy, Sustainability and the Environment, Public Health, Environmental and Occupational Health, Tropics, 15. Life on land, Earth sciences, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental science, environmental drivers, Satellite, ddc:500
Abstract: Year-to-year variability in CO2 fluxes can yield insight into climate-carbon cycle relationships, a fundamental yet uncertain aspect of the terrestrial carbon cycle. In this study, we use global observations from NASA’s Orbiting Carbon Observatory-2 (OCO-2) satellite for years 2015–2019 and a geostatistical inverse model to evaluate 5 years of interannual variability (IAV) in CO2 fluxes and its relationships with environmental drivers. OCO-2 launched in late 2014, and we specifically evaluate IAV during the time period when OCO-2 observations are available. We then compare inferences from OCO-2 with state-of-the-art process-based models (terrestrial biosphere model, TBMs). Results from OCO-2 suggest that the tropical grasslands biome (including grasslands, savanna, and agricultural lands within the tropics) makes contributions to global IAV during the 5 year study period that are comparable to tropical forests, a result that differs from a majority of TBMs. Furthermore, existing studies disagree on the environmental variables that drive IAV during this time period, and the analysis using OCO-2 suggests that both temperature and precipitation make comparable contributions. TBMs, by contrast, tend to estimate larger IAV during this time and usually estimate larger relative contributions from the extra-tropics. With that said, TBMs show little consensus on both the magnitude and the contributions of different regions to IAV. We further find that TBMs show a wide range of responses on the relationships of CO2 fluxes with annual anomalies in temperature and precipitation, and these relationships across most of the TBMs have a larger magnitude than inferred from OCO-2. Overall, the findings of this study highlight large uncertainties in process-based estimates of IAV during recent years and provide an avenue for evaluating these processes against inferences from OCO-2.
Published: 2021
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3. Modeling suggests fossil fuel emissions have been driving increased land carbon uptake since the turn of the 20th Century

Author: Anna M. Michalak, Deborah N. Huntzinger, Yaxing Wei, Kevin Schaefer, Joshua B. Fisher, Yuanyuan Fang, and Christopher R. Schwalm
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Life on Land, lcsh:Medicine, 010603 evolutionary biology, 01 natural sciences, Article, Deposition (geology), Anthropocene, Environmental protection, lcsh:Science, Author Correction, Primary productivity, 0105 earth and related environmental sciences, Multidisciplinary, Ecology, lcsh:R, Global warming, Carbon uptake, Tropics, Global change, Biogeochemistry, Fossil fuel emissions, Climate Action, Environmental sciences, Environmental science, lcsh:Q, Climate sciences
Abstract: Terrestrial vegetation removes CO2 from the atmosphere; an important climate regulation service that slows global warming. This 119 Pg C per annum transfer of CO2 into plants—gross primary productivity (GPP)—is the largest land carbon flux globally. While understanding past and anticipated future GPP changes is necessary to support carbon management, the factors driving long-term changes in GPP are largely unknown. Here we show that 1901 to 2010 changes in GPP have been dominated by anthropogenic activity. Our dual constraint attribution approach provides three insights into the spatiotemporal patterns of GPP change. First, anthropogenic controls on GPP change have increased from 57% (1901 decade) to 94% (2001 decade) of the vegetated land surface. Second, CO2 fertilization and nitro gen deposition are the most important drivers of change, 19.8 and 11.1 Pg C per annum (2001 decade) respectively, especially in the tropics and industrialized areas since the 1970’s. Third, changes in climate have functioned as fertilization to enhance GPP (1.4 Pg C per annum in the 2001 decade). These findings suggest that, from a land carbon balance perspective, the Anthropocene began over 100 years ago and that global change drivers have allowed GPP uptake to keep pace with anthropogenic emissions.
Published: 2020
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4. Linking global terrestrial CO2 fluxes and environmental drivers using OCO-2 and a geostatistical inverse model

Author: Deborah N. Huntzinger, Zichong Chen, Junjie Liu, Daven K. Henze, Kelley C. Wells, and Scot M. Miller
Subjects: Flux (metallurgy), 010504 meteorology & atmospheric sciences, Photosynthetically active radiation, Biome, Environmental science, Satellite, Precipitation, Atmospheric model, Atmospheric sciences, 01 natural sciences, 0105 earth and related environmental sciences, Carbon cycle, Latitude
Abstract: Observations from the OCO-2 satellite, launched in July 2014, have been used to estimate CO2 fluxes in many regions of the globe and provide new insight on the global carbon cycle. A challenge now is to not only estimate fluxes using satellite observations but also to understand how these fluxes are connected to variations in environmental conditions. In this study, we specifically evaluate the capabilities and limitations of utilizing current OCO-2 observations to infer connections between CO2 fluxes and underlying environmental variables. To do so, we adapt geostatistical inverse modeling to satellite-based applications and evaluate a case study for year 2016 using OCO-2. One unique aspect of the geostatistical approach is that we can use estimates of environmental and meteorological variables to help estimate CO2 fluxes in place of a traditional prior flux model. We are able to quantify the relationships between CO2 fluxes and a few environmental variables across global biomes; we find that a simple combination of air temperature, daily precipitation, and photosynthetically active radiation (PAR) can describe almost 90 % of the variability in CO2 fluxes as seen through OCO-2 observations. PAR is an adept predictor of fluxes across mid-to-high latitudes, whereas a combined set of air temperature and precipitation shows strong explanatory power across tropical biomes. However, we are unable to quantify relationships with additional environmental variables because many variables are correlated or colinear when passed through an atmospheric model and averaged across a total atmospheric column. Overall, we estimate a global net biospheric flux of −1.73 ± 0.53 GtC in year 2016, in close agreement with recent inverse modeling studies using OCO-2 retrievals as observational constraints.
Published: 2020
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5. Enhanced peak growth of global vegetation and its key mechanisms

Author: Yiqi Luo, Kun Huang, Kevin Schaefer, Yang Qiao, Robert B. Cook, Chenyu Bian, Joshua B. Fisher, Xiaoni Xu, Liming Yan, Anders Ahlström, Jiquan Chen, Ying-Ping Wang, Anna M. Michalak, Deborah N. Huntzinger, Jing Wang, Yuanyuan Fang, Jianyang Xia, Zhao Li, Christopher R. Schwalm, Yaxing Wei, and Erqian Cui
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Ecology, Plant Development, Biosphere, Seasonality, Atmospheric sciences, medicine.disease, 010603 evolutionary biology, 01 natural sciences, Photosynthetic capacity, Normalized Difference Vegetation Index, Remote Sensing Technology, medicine, Environmental science, Terrestrial ecosystem, Ecosystem, Seasons, Photosynthesis, medicine.symptom, Ecosystem ecology, Vegetation (pathology), Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences
Abstract: The annual peak growth of vegetation is critical in characterizing the capacity of terrestrial ecosystem productivity and shaping the seasonality of atmospheric CO2 concentrations. The recent greening of global lands suggests an increasing trend of terrestrial vegetation growth, but whether or not the peak growth has been globally enhanced still remains unclear. Here, we use two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in annual peak vegetation growth (that is, GPPmax and NDVImax). We demonstrate that the peak in the growth of global vegetation has been linearly increasing during the past three decades. About 65% of the NDVImax variation is evenly explained by expanding croplands (21%), rising CO2 (22%) and intensifying nitrogen deposition (22%). The contribution of expanding croplands to the peak growth trend is substantiated by measurements from eddy-flux towers, sun-induced chlorophyll fluorescence and a global database of plant traits, all of which demonstrate that croplands have a higher photosynthetic capacity than other vegetation types. The large contribution of CO2 is also supported by a meta-analysis of 466 manipulative experiments and 15 terrestrial biosphere models. Furthermore, we show that the contribution of GPPmax to the change in annual GPP is less in the tropics than in other regions. These multiple lines of evidence reveal an increasing trend in the peak growth of global vegetation. The findings highlight the important roles of agricultural intensification and atmospheric changes in reshaping the seasonality of global vegetation growth.
Published: 2018
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6. Global patterns of drought recovery

Author: Anna M. Michalak, Atul K. Jain, Robert B. Cook, Daniel J. Hayes, Adam Wolf, Deborah N. Huntzinger, John D. Shaw, Kevin Schaefer, William R. L. Anderegg, Maoyi Huang, Yaxing Wei, George W. Koch, Kiona Ogle, Franco Biondi, Hanqin Tian, Yuanyuan Fang, Marcy E. Litvak, Christopher R. Schwalm, and Joshua B. Fisher
Subjects: Carbon Sequestration, Internationality, Time Factors, 010504 meteorology & atmospheric sciences, Rain, Biodiversity, 010501 environmental sciences, Carbon sequestration, Global Warming, History, 21st Century, 01 natural sciences, Wildfires, Soil, Spatio-Temporal Analysis, Drought recovery, Tropical climate, Ecosystem, 0105 earth and related environmental sciences, Tropical Climate, Multidisciplinary, Ecology, Global warming, Temperature, Tropics, Carbon sink, Carbon Dioxide, History, 20th Century, Droughts, Environmental science
Abstract: Drought, a recurring phenomenon with major impacts on both human and natural systems, is the most widespread climatic extreme that negatively affects the land carbon sink. Although twentieth-century trends in drought regimes are ambiguous, across many regions more frequent and severe droughts are expected in the twenty-first century. Recovery time-how long an ecosystem requires to revert to its pre-drought functional state-is a critical metric of drought impact. Yet the factors influencing drought recovery and its spatiotemporal patterns at the global scale are largely unknown. Here we analyse three independent datasets of gross primary productivity and show that, across diverse ecosystems, drought recovery times are strongly associated with climate and carbon cycle dynamics, with biodiversity and CO2 fertilization as secondary factors. Our analysis also provides two key insights into the spatiotemporal patterns of drought recovery time: first, that recovery is longest in the tropics and high northern latitudes (both vulnerable areas of Earth's climate system) and second, that drought impacts (assessed using the area of ecosystems actively recovering and time to recovery) have increased over the twentieth century. If droughts become more frequent, as expected, the time between droughts may become shorter than drought recovery time, leading to permanently damaged ecosystems and widespread degradation of the land carbon sink.
Published: 2017
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7. Reduced North American terrestrial primary productivity linked to anomalous Arctic warming

Author: Su-Jong Jeong, Jong-Seong Kug, Deborah N. Huntzinger, Kevin Schaefer, Anna M. Michalak, Jin-Soo Kim, Yaxing Wei, and Christopher R. Schwalm
Subjects: 0301 basic medicine, 010504 meteorology & atmospheric sciences, Arctic dipole anomaly, Northern Hemisphere, 01 natural sciences, Carbon cycle, 03 medical and health sciences, 030104 developmental biology, Arctic, Climatology, General Earth and Planetary Sciences, Environmental science, Precipitation, Productivity, geographic locations, Primary productivity, 0105 earth and related environmental sciences, Teleconnection
Abstract: Warming temperatures in the Northern Hemisphere have enhanced terrestrial productivity. Despite the warming trend, North America has experienced more frequent and more intense cold weather events during winters and springs. These events have been linked to anomalous Arctic warming since 1990, and may affect terrestrial processes. Here we analyse multiple observation data sets and numerical model simulations to evaluate links between Arctic temperatures and primary productivity in North America. We find that positive springtime temperature anomalies in the Arctic have led to negative anomalies in gross primary productivity over most of North America during the last three decades, which amount to a net productivity decline of 0.31 PgC yr−1 across the continent. This decline is mainly explained by two factors: severe cold conditions in northern North America and lower precipitation in the South Central United States. In addition, United States crop-yield data reveal that during years experiencing anomalous warming in the Arctic, yields declined by approximately 1 to 4% on average, with individual states experiencing declines of up to 20%. We conclude that the strengthening of Arctic warming anomalies in the past decades has remotely reduced productivity over North America. Anomalous Arctic warming has been linked to colder North American winters. Analyses of weather and productivity observations reveal that Arctic–North American teleconnections reduce gross primary productivity in the US.
Published: 2017
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8. Climate-driven risks to the climate mitigation potential of forests

Author: Stephen W. Pacala, James T. Randerson, Philippe Ciais, William R. L. Anderegg, Grayson Badgley, Christopher B. Field, John Nickerson, Jeffrey A. Hicke, Robert B. Jackson, Deborah N. Huntzinger, Jeremy Freeman, Anna T. Trugman, Scott J. Goetz, Danny Cullenward, Christa M. Anderson, Ann M. Bartuska, SCHOOL OF BIOLOGICAL SCIENCES UNIVERSITY OF UTAH SALT LAKE CITY USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), University of California [Santa Barbara] (UCSB), University of California, World Wildlife Fund, Washington, RESOURCES FOR THE FUTURE WASHINGTON DC USA, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Stanford University, School of Informatics, Computing, and Cyber Systems (SICCS), Northern Arizona University [Flagstaff], DEPARTMENT OF GEOGRAPHY UNIVERSITY OF IDAHO MOSCOW IDAHO USA, PRINCETON UNIVERSITY DEPARTMENT OF ECOLOGY AND EVOLUTIONARY BIOLOGY PRINCETON USA, DEPARTMENT OF EARTH SYSTEM SCIENCES UNIVERSITY OF CALIFORNIA IRVINE CA USA, University of California [Santa Barbara] (UC Santa Barbara), University of California (UC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Sociology of scientific knowledge, Carbon Sequestration, 010504 meteorology & atmospheric sciences, Policy making, Climate Change, Climate change, Carbon sequestration, Forests, 01 natural sciences, Natural (archaeology), Fires, 03 medical and health sciences, Policy Making, 030304 developmental biology, 0105 earth and related environmental sciences, 0303 health sciences, Multidisciplinary, business.industry, Environmental resource management, Carbon sink, Vegetation, 15. Life on land, [SHS.ECO]Humanities and Social Sciences/Economics and Finance, Droughts, 13. Climate action, Environmental science, business
Abstract: Risks to mitigation potential of forests Much recent attention has focused on the potential of trees and forests to mitigate ongoing climate change by acting as sinks for carbon. Anderegg et al. review the growing evidence that forests' climate mitigation potential is increasingly at risk from a range of adversities that limit forest growth and health. These include physical factors such as drought and fire and biotic factors, including the depredations of insect herbivores and fungal pathogens. Full assessment and quantification of these risks, which themselves are influenced by climate, is key to achieving science-based policy outcomes for effective land and forest management. Science , this issue p. eaaz7005
Published: 2020
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9. Field-experiment constraints on the enhancement of the terrestrial carbon sink by CO2 fertilization

Author: Yuanyuan Fang, Ning Zeng, Xiaoying Shi, Trevor F. Keenan, Akihiko Ito, Philippe Ciais, Kai Wang, Shilong Piao, M. A. Arain, Qiuan Zhu, Mengtian Huang, Tao Wang, Jian Song, Joshua B. Fisher, Anna M. Michalak, Josep Peñuelas, Changhui Peng, Atul K. Jain, Chris Huntingford, Deborah N. Huntzinger, Yongwen Liu, Jiafu Mao, Yaxing Wei, Thomas Gasser, Hanqin Tian, Ivan A. Janssens, Maoyi Huang, Shiqiang Wan, Christopher R. Schwalm, Hui Yang, Xuhui Wang, Benjamin Poulter, Han Wang, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], International Institute for Applied Systems Analysis [Laxenburg] (IIASA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Henan University, Institut National des Langues et Civilisations Orientales (Inalco), The Center for Applied Genomics, Children’s Hospital of Philadelphia (CHOP ), Department of Biology, University of Antwerp (UA), Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Chemistry [University of Houston], University of Houston, University of Oxford, Northern Arizona University [Flagstaff], National Institute for Environmental Studies (NIES), Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Environmental Sciences Division [Oak Ridge], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Carnegie Observatories, Carnegie Institution for Science, Université du Québec à Trois-Rivières (UQTR), NASA Goddard Space Flight Center (GSFC), Graduate School of Geography, Clark University, Shandong Agricultural University (SDAU), Northwest A and F University, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Henan University, Kaifeng (HENU), Henan University, Kaifeng, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), University of Oxford [Oxford], Carnegie Institution for Science [Washington], Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Life on Land, Field experiment, Physics, Northern Hemisphere, Carbon sink, 15. Life on land, Carbon sequestration, 010502 geochemistry & geophysics, Atmospheric sciences, 01 natural sciences, Arctic, 13. Climate action, Temperate climate, General Earth and Planetary Sciences, Environmental science, Meteorology & Atmospheric Sciences, Terrestrial ecosystem, Ecosystem, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Clarifying how increased atmospheric CO2 concentration (eCO2) contributes to accelerated land carbon sequestration remains important since this process is the largest negative feedback in the coupled carbon–climate system. Here, we constrain the sensitivity of the terrestrial carbon sink to eCO2 over the temperate Northern Hemisphere for the past five decades, using 12 terrestrial ecosystem models and data from seven CO2 enrichment experiments. This constraint uses the heuristic finding that the northern temperate carbon sink sensitivity to eCO2 is linearly related to the site-scale sensitivity across the models. The emerging data-constrained eCO2 sensitivity is 0.64 ± 0.28 PgC yr−1 per hundred ppm of eCO2. Extrapolating worldwide, this northern temperate sensitivity projects the global terrestrial carbon sink to increase by 3.5 ± 1.9 PgC yr−1 for an increase in CO2 of 100 ppm. This value suggests that CO2 fertilization alone explains most of the observed increase in global land carbon sink since the 1960s. More CO2 enrichment experiments, particularly in boreal, arctic and tropical ecosystems, are required to explain further the responsible processes. The northern temperate carbon sink is estimated to increase by 0.64 PgC each year for each increase in atmospheric CO2 concentrations by 100 ppm, suggests an analysis of data from field experiments at 7 sites constraints.
Published: 2019
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10. Global vegetation biomass production efficiency constrained by models and observations

Author: Anna M. Michalak, Changhui Peng, Yuanyuan Fang, Daniel J. Hayes, Dahe Qin, Kai Wang, Atul K. Jain, Yongwen Liu, Campioli Matteo, Akihiko Ito, Philippe Ciais, Sara Vicca, Josep Peñuelas, Daniel S. Goll, M. Altaf Arain, Deborah N. Huntzinger, Jiafu Mao, Xiaoying Shi, Qiuan Zhu, Yaxing Wei, Christopher R. Schwalm, Ivan A. Janssens, Kevin Schaefer, Benjamin Poulter, Xiangyi Li, Shushi Peng, Joshua B. Fisher, Yue He, Daniel M. Ricciuto, Hanqin Tian, Ning Zeng, University of California [San Francisco] (UCSF), University of California, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), School of Geography and earth sciences, McMaster University [Hamilton, Ontario], Department of Chemistry [University of Houston], University of Houston, University of Oxford [Oxford], Cyprus Oceanography Center, University of Cyprus (UCY), Northern Arizona University [Flagstaff], National Institute for Environmental Studies (NIES), Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Department of Biology, University of Antwerp (UA), Environmental Sciences Division [Oak Ridge], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Carnegie Observatories, Carnegie Institution for Science [Washington], Université du Québec à Trois-Rivières (UQTR), Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Montana State University (MSU), Graduate School of Geography, Clark University, Shandong Agricultural University (SDAU), Department of Biology, Centre of Excellence PLECO (Plant and Vegetation Ecology), Northwest A and F University, University of California [San Francisco] (UC San Francisco), University of California (UC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Oxford, University of Cyprus [Nicosia] (UCY), and Carnegie Institution for Science
Subjects: 0106 biological sciences, Carbon Sequestration, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, Photosynthesis, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, Carbon Cycle, Trees, Environmental Chemistry, Compounds of carbon, Ecosystem, Biomass, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Biology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, chemistry.chemical_classification, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Biomass (ecology), Ecology, Carbon sink, Primary production, 15. Life on land, Carbon Dioxide, Carbon, Chemistry, chemistry, 13. Climate action, Environmental science
Abstract: Plants use only a fraction of their photosynthetically derived carbon for biomass production (BP). The biomass production efficiency (BPE), defined as the ratio of BP to photosynthesis, and its variation across and within vegetation types is poorly understood, which hinders our capacity to accurately estimate carbon turnover times and carbon sinks. Here, we present a new global estimation of BPE obtained by combining field measurements from 113 sites with 14 carbon cycle models. Our best estimate of global BPE is 0.41 +/- 0.05, excluding cropland. The largest BPE is found in boreal forests (0.48 +/- 0.06) and the lowest in tropical forests (0.40 +/- 0.04). Carbon cycle models overestimate BPE, although models with carbon-nitrogen interactions tend to be more realistic. Using observation-based estimates of global photosynthesis, we quantify the global BP of non-cropland ecosystems of 41 +/- 6 Pg C/year. This flux is less than net primary production as it does not contain carbon allocated to symbionts, used for exudates or volatile carbon compound emissions to the atmosphere. Our study reveals a positive bias of 24 +/- 11% in the model-estimated BP (10 of 14 models). When correcting models for this bias while leaving modeled carbon turnover times unchanged, we found that the global ecosystem carbon storage change during the last century is decreased by 67% (or 58 Pg C).
Published: 2019
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11. Uncertainty analysis of terrestrial net primary productivity and net biome productivity in China during 1901-2005

Author: Bo Li, Guodong Zhang, Jiaxuan Li, Deborah N. Huntzinger, Yiqi Luo, Benjamin Poulter, Joshua B. Fisher, Xiaoying Shi, Jihua Meng, Nicholas C. Parazoo, Zhiqiang Gao, Ning Zeng, Xuhui Zhou, Wei Yan, Atul K. Jain, Yong He, Rui Sun, Fulu Tao, Christopher R. Schwalm, Li Dan, Wenquan Zhu, Qiuan Zhu, Hanqin Tian, Anna M. Michalak, Changhui Peng, Junjiong Shao, Yaxing Wei, and Jiafu Mao
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Ecology, Biome, Paleontology, Soil Science, Primary production, Forestry, Global change, Land cover, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, Soil respiration, Climatology, Environmental science, China, Productivity, Uncertainty analysis, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: Despite the importance of net primary productivity (NPP) and net biome productivity (NBP), estimates of NPP and NBP for China are highly uncertain. To investigate the main sources of uncertainty, we synthesized model estimates of NPP and NBP for China from published literature and the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP). The literature-based results showed that total NPP and NBP in China were 3.35 ± 1.25 and 0.14 ± 0.094 Pg C yr−1, respectively. Classification and regression tree analysis based on literature data showed that model type was the primary source of the uncertainty, explaining 36% and 64% of the variance in NPP and NBP, respectively. Spatiotemporal scales, land cover conditions, inclusion of the N cycle, and effects of N addition also contributed to the overall uncertainty. Results based on the MsTMIP data suggested that model structures were overwhelmingly important (>90%) for the overall uncertainty compared to simulations with different combinations of time-varying global change factors. The interannual pattern of NPP was similar among diverse studies and increased by 0.012 Pg C yr−1 during 1981–2000. In addition, high uncertainty in China's NPP occurred in areas with high productivity, whereas NBP showed the opposite pattern. Our results suggest that to significantly reduce uncertainty in estimated NPP and NBP, model structures should be substantially tested on the basis of empirical results. To this end, coordinated distributed experiments with multiple global change factors might be a practical approach that can validate specific structures of different models.
Published: 2016
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12. Technical note: 3-hourly temporal downscaling of monthly global terrestrial biosphere model net ecosystem exchange

Author: Deborah N. Huntzinger, Christopher R. Schwalm, Munish Sikka, Junjie Liu, and Joshua B. Fisher
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, Ensemble average, lcsh:Life, Technical note, Inversion (meteorology), 010603 evolutionary biology, 01 natural sciences, Standard deviation, lcsh:Geology, lcsh:QH501-531, lcsh:QH540-549.5, Climatology, Net ecosystem exchange, Environmental science, lcsh:Ecology, Plant phenology, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, Downscaling
Abstract: The land surface provides a boundary condition to atmospheric forward and flux inversion models. These models require prior estimates of CO2 fluxes at relatively high temporal resolutions (e.g., 3-hourly) because of the high frequency of atmospheric mixing and wind heterogeneity. However, land surface model CO2 fluxes are often provided at monthly time steps, typically because the land surface modeling community focuses more on time steps associated with plant phenology (e.g., seasonal) than on sub-daily phenomena. Here, we describe a new dataset created from 15 global land surface models and 4 ensemble products in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), temporally downscaled from monthly to 3-hourly output. We provide 3-hourly output for each individual model over 7 years (2004–2010), as well as an ensemble mean, a weighted ensemble mean, and the multi-model standard deviation. Output is provided in three different spatial resolutions for user preferences: 0.5° × 0.5°, 2.0° × 2.5°, and 4.0° × 5.0° (latitude × longitude). These data are publicly available from doi:10.3334/ORNLDAAC/1315.
Published: 2018

13. Accelerating rates of Arctic carbon cycling revealed by long-term atmospheric CO 2 measurements

Author: Colm Sweeney, Su-Jong Jeong, Anna M. Michalak, A. Anthony Bloom, Nicholas C. Parazoo, Chunmiao Zheng, Gabriela Schaepman-Strub, David Medvigy, Deborah N. Huntzinger, Christopher R. Schwalm, Charles E. Miller, and David S. Schimel
Subjects: 0106 biological sciences, Multidisciplinary, 010504 meteorology & atmospheric sciences, Growing season, chemistry.chemical_element, Permafrost, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Tundra, Carbon cycle, Arctic, chemistry, Respiration, Ecosystem, Carbon, 0105 earth and related environmental sciences
Abstract: The contemporary Arctic carbon balance is uncertain, and the potential for a permafrost carbon feedback of anywhere from 50 to 200 petagrams of carbon (Schuur et al., 2015) compromises accurate 21st-century global climate system projections. The 42-year record of atmospheric CO2 measurements at Barrow, Alaska (71.29 N, 156.79 W), reveals significant trends in regional land-surface CO2 anomalies (ΔCO2), indicating long-term changes in seasonal carbon uptake and respiration. Using a carbon balance model constrained by ΔCO2, we find a 13.4% decrease in mean carbon residence time (50% confidence range = 9.2 to 17.6%) in North Slope tundra ecosystems during the past four decades, suggesting a transition toward a boreal carbon cycling regime. Temperature dependencies of respiration and carbon uptake suggest that increases in cold season Arctic labile carbon release will likely continue to exceed increases in net growing season carbon uptake under continued warming trends.
Published: 2018
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14. Missing pieces to modeling the Arctic-Boreal puzzle

Author: Yiqi Luo, Christopher S.R. Neigh, Benjamin Poulter, Sarah Chadburn, Hélène Genet, Yongkang Xue, Zong-Liang Yang, Akihiko Ito, Philippe Ciais, Thomas A. Douglas, Christopher R. Schwalm, Daniel J. Hayes, Scott J. Goetz, Weile Wang, Hanqin Tian, P. C. Griffith, Eric Stofferahn, Charles E. Miller, Joshua B. Fisher, Ning Zeng, Kevin Schaefer, Zhen Zhang, Stan D. Wullschleger, Brendan M. Rogers, Deborah N. Huntzinger, Abhishek Chatterjee, Oliver Sonnentag, University of Oxford, Cyprus Oceanography Center, University of Cyprus [Nicosia] (UCY), Northern Arizona University [Flagstaff], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), University of Oklahoma (OU), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, NASA Goddard Space Flight Center (GSFC), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Universities Space Research Association (USRA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), U.S. Army Cold Regions Research and Engineering Laboratory Fort Wainwright, Institute of Arctic Biology, University of Alaska [Fairbanks] (UAF), National Institute for Environmental Studies (NIES), Montana State University (MSU), Department of Geography, Université Catholique de Louvain = Catholic University of Louvain (UCL), Auburn University (AU), Department of Geography [Los Angeles], University of California [Los Angeles] (UCLA), University of California (UC)-University of California (UC), Department of Geological Sciences, The University of Texas Health Science Center at Houston (UTHealth), Institute of Atmospheric Physics [Beijing] (IAP), Chinese Academy of Sciences [Beijing] (CAS), The School of Electronic and Electrical Engineering, University of Nottingham, UK (UON), University of Oxford [Oxford], University of Cyprus (UCY), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), INSTITUTE OF ARCTIC BIOLOGY UNIVERSITY OF ALASKA FAIRBANKS USA, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and University of California-University of California
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Ecosystem model, ABoVE, arctic, boreal, Meteorology & Atmospheric Sciences, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, requirements, uncertainty, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Mathematics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Data collection, model, Renewable Energy, Sustainability and the Environment, Chatterjee, Public Health, Environmental and Occupational Health, Vegetation, Field (geography), The arctic, Arctic, Boreal, Physical geography, arctic boreal vulnerability experiment
Abstract: Author(s): Fisher, JB; Hayes, DJ; Schwalm, CR; Huntzinger, DN; Stofferahn, E; Schaefer, K; Luo, Y; Wullschleger, SD; Goetz, S; Miller, CE; Griffith, P; Chadburn, S; Chatterjee, A; Ciais, P; Douglas, TA; Genet, H; Ito, A; Neigh, CSR; Poulter, B; Rogers, BM; Sonnentag, O; Tian, H; Wang, W; Xue, Y; Yang, ZL; Zeng, N; Zhang, Z | Abstract: NASA has launched the decade-long Arctic-Boreal Vulnerability Experiment (ABoVE). While the initial phases focus on field and airborne data collection, early integration with modeling activities is important to benefit future modeling syntheses. We compiled feedback from ecosystem modeling teams on key data needs, which encompass carbon biogeochemistry, vegetation, permafrost, hydrology, and disturbance dynamics. A suite of variables was identified as part of this activity with a critical requirement that they are collected concurrently and representatively over space and time. Individual projects in ABoVE may not capture all these needs, and thus there is both demand and opportunity for the augmentation of field observations, and synthesis of the observations that are collected, to ensure that science questions and integrated modeling activities are successfully implemented.
Published: 2018
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15. Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

Author: Xiaoying Shi, Akihiko Ito, Philippe Ciais, Jiafu Mao, Weile Wang, Benjamin Poulter, Yaxing Wei, Anna M. Michalak, Daniel M. Ricciuto, Atul K. Jain, Sha Zhou, Deborah N. Huntzinger, Shuli Niu, Christopher R. Schwalm, Yao Zhang, Guangqian Wang, Yuefei Huang, Joshua B. Fisher, Bofu Yu, Northern Arizona University [Flagstaff], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ECE Department, (ECE), University of California [Davis] (UC Davis), University of California (UC)-University of California (UC), University of Oxford, Carnegie Observatories, Carnegie Institution for Science, Montana State University (MSU), Synth Res Ctr Chinese Ecosyst Res Network, Institute of Geographic Sciences and Natural Resources Research, Climate Change Science Institute [Oak Ridge] (CCSI), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Environmental Sciences Division [Oak Ridge], National Institute for Environmental Studies (NIES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of California-University of California, University of Oxford [Oxford], and Carnegie Institution for Science [Washington]
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Vapour Pressure Deficit, interannual variability, Oceanography, 010603 evolutionary biology, 01 natural sciences, Atmospheric Sciences, Evapotranspiration, Environmental Chemistry, Meteorology & Atmospheric Sciences, Ecosystem, structure, Water cycle, Water-use efficiency, Leaf area index, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, General Environmental Science, Transpiration, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, atmospheric CO2, Global and Planetary Change, 15. Life on land, attribution, Climate Action, trend, Geochemistry, 13. Climate action, Climatology, physiology, Environmental science, Terrestrial ecosystem
Abstract: Author(s): Zhou, S; Yu, B; Schwalm, CR; Ciais, P; Zhang, Y; Fisher, JB; Michalak, AM; Wang, W; Poulter, B; Huntzinger, DN; Niu, S; Mao, J; Jain, A; Ricciuto, DM; Shi, X; Ito, A; Wei, Y; Huang, Y; Wang, G | Abstract: Water use efficiency (WUE), defined as the ratio of gross primary productivity and evapotranspiration at the ecosystem scale, is a critical variable linking the carbon and water cycles. Incorporating a dependency on vapor pressure deficit, apparent underlying WUE (uWUE) provides a better indicator of how terrestrial ecosystems respond to environmental changes than other WUE formulations. Here we used 20th century simulations from four terrestrial biosphere models to develop a novel variance decomposition method. With this method, we attributed variations in apparent uWUE to both the trend and interannual variation of environmental drivers. The secular increase in atmospheric CO2 explained a clear majority of total variation (66n±n32%: meann±none standard deviation), followed by positive trends in nitrogen deposition and climate, as well as a negative trend in land use change. In contrast, interannual variation was mostly driven by interannual climate variability. To analyze the mechanism of the CO2 effect, we partitioned the apparent uWUE into the transpiration ratio (transpiration over evapotranspiration) and potential uWUE. The relative increase in potential uWUE parallels that of CO2, but this direct CO2 effect was offset by 20n±n4% by changes in ecosystem structure, that is, leaf area index for different vegetation types. However, the decrease in transpiration due to stomatal closure with rising CO2 was reduced by 84% by an increase in leaf area index, resulting in small changes in the transpiration ratio. CO2 concentration thus plays a dominant role in driving apparent uWUE variations over time, but its role differs for the two constituent components: potential uWUE and transpiration.
Published: 2017
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16. The North American Carbon Program Multi-Scale Synthesis and Terrestrial Model Intercomparison Project – Part 1: Overview and experimental design

Author: Xiaoying Shi, Deborah N. Huntzinger, Shuguang Liu, Ning Zeng, Weile Wang, Benjamin Poulter, G. Berthier, Shushi Peng, Yaxing Wei, Christopher R. Schwalm, Fang Zhao, Kevin Schaefer, Andrew R. Jacobson, Robert B. Cook, Wilfred M. Post, Jiafu Mao, D. Riccuito, Maoyi Huang, Anna M. Michalak, Chaoqun Lu, Changhui Peng, Daniel J. Hayes, Huimin Lei, Akihiko Ito, Hanqin Tian, Anthony W. King, Qiuan Zhu, Northern Arizona University [Flagstaff], Carnegie Institution for Science [Washington], National Snow and Ice Data Center (NSIDC), University of Colorado [Boulder], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Pacific Northwest National Laboratory (PNNL), National Institute for Environmental Studies (NIES), Auburn University (AU), Université du Québec à Montréal = University of Québec in Montréal (UQAM), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Aeronautics and Space Administration, Partenaires INRAE, Department of Atmospheric and Oceanic Science [College Park] (AOSC), University of Maryland [College Park], University of Maryland System-University of Maryland System, Northwest A and F University, Carnegie Institution for Science, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and National Aeronautics and Space Administration (NASA)
Subjects: 0106 biological sciences, Nutrient cycle, 010504 meteorology & atmospheric sciences, Meteorology, Scale (ratio), Biomass, chemistry.chemical_element, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Carbon cycle, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, Biosphere, Soil carbon, Vegetation, 15. Life on land, lcsh:Geology, chemistry, 13. Climate action, Environmental science, Carbon
Abstract: Terrestrial biosphere models (TBMs) have become an integral tool for extrapolating local observations and understanding of land-atmosphere carbon exchange to larger regions. The North American Carbon Program (NACP) Multi-scale synthesis and Terrestrial Model Intercomparison Project (MsTMIP) is a formal model intercomparison and evaluation effort focused on improving the diagnosis and attribution of carbon exchange at regional and global scales. MsTMIP builds upon current and past synthesis activities, and has a unique framework designed to isolate, interpret, and inform understanding of how model structural differences impact estimates of carbon uptake and release. Here we provide an overview of the MsTMIP effort and describe how the MsTMIP experimental design enables the assessment and quantification of TBM structural uncertainty. Model structure refers to the types of processes considered (e.g. nutrient cycling, disturbance, lateral transport of carbon), and how these processes are represented (e.g. photosynthetic formulation, temperature sensitivity, respiration) in the models. By prescribing a common experimental protocol with standard spin-up procedures and driver data sets, we isolate any biases and variability in TBM estimates of regional and global carbon budgets resulting from differences in the models themselves (i.e. model structure) and model-specific parameter values. An initial intercomparison of model structural differences is represented using hierarchical cluster diagrams (a.k.a. dendrograms), which highlight similarities and differences in how models account for carbon cycle, vegetation, energy, and nitrogen cycle dynamics. We show that, despite the standardized protocol used to derive initial conditions, models show a high degree of variation for GPP, total living biomass, and total soil carbon, underscoring the influence of differences in model structure and parameterization on model estimates.
Published: 2013
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17. Uncertainty in the response of terrestrial carbon sink to environmental drivers undermines carbon-climate feedback predictions

Author: Xiaoying Shi, Anna M. Michalak, Nicholas C. Parazoo, Weile Wang, Chaoqun Lu, Akihiko Ito, Daniel J. Hayes, Anthony W. King, Joshua B. Fisher, Christopher R. Schwalm, Benjamin Poulter, Yaxing Wei, Yuanyuan Fang, Kevin Schaefer, Huimin Lei, Atul K. Jain, Robert B. Cook, P. Ciais, Deborah N. Huntzinger, Maoyi Huang, Jiafu Mao, Shushi Peng, Hanqin Tian, Fang Zhao, Daniel M. Ricciuto, Fabienne Maignan, Ning Zeng, Northern Arizona University [Flagstaff], Carnegie Institution for Science, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, University of Colorado [Boulder], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), University of Maine, Pacific Northwest National Laboratory (PNNL), National Institute for Environmental Studies (NIES), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Tsinghua University [Beijing] (THU), Department of Ecology, Evolution and Organismal Biology, Iowa State University (ISU), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Montana State University (MSU), Environmental Sciences Division [Oak Ridge], UT-Battelle, LLC-UT-Battelle, LLC, Auburn University (AU), NASA Ames Research Center (ARC), Department of Atmospheric and Oceanic Science [College Park] (AOSC), University of Maryland [College Park], University of Maryland System-University of Maryland System, Carnegie Institution for Science [Washington], Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, Life on Land, Science, chemistry.chemical_element, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Article, Carbon cycle, Atmosphere, Predictability, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, Multidisciplinary, Ecology, Carbon sink, 15. Life on land, Land area, Climate Action, chemistry, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Environmental science, Medicine, Terrestrial ecosystem, Cycling, Carbon
Abstract: Terrestrial ecosystems play a vital role in regulating the accumulation of carbon (C) in the atmosphere. Understanding the factors controlling land C uptake is critical for reducing uncertainties in projections of future climate. The relative importance of changing climate, rising atmospheric CO2, and other factors, however, remains unclear despite decades of research. Here, we use an ensemble of land models to show that models disagree on the primary driver of cumulative C uptake for 85% of vegetated land area. Disagreement is largest in model sensitivity to rising atmospheric CO2 which shows almost twice the variability in cumulative land uptake since 1901 (1 s.d. of 212.8 PgC vs. 138.5 PgC, respectively). We find that variability in CO2 and temperature sensitivity is attributable, in part, to their compensatory effects on C uptake, whereby comparable estimates of C uptake can arise by invoking different sensitivities to key environmental conditions. Conversely, divergent estimates of C uptake can occur despite being based on the same environmental sensitivities. Together, these findings imply an important limitation to the predictability of C cycling and climate under unprecedented environmental conditions. We suggest that the carbon modeling community prioritize a probabilistic multi-model approach to generate more robust C cycle projections.
Published: 2017
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18. North American CO2 exchange: inter-comparison of modeled estimates with results from a fine-scale atmospheric inversion

Author: Marc Fischer, K. L. Mueller, Thomas Nehrkorn, Anna M. Michalak, Colm Sweeney, Vineet Yadav, Janusz Eluszkiewicz, J. Henderson, Gabrielle Pétron, Sharon Gourdji, Deborah N. Huntzinger, John C. Lin, Arlyn E. Andrews, Deyong Wen, and Michael E. Trudeau
Subjects: 010504 meteorology & atmospheric sciences, Dormant season, Residual biomass, Inversion (meteorology), 010501 environmental sciences, 01 natural sciences, Carbon cycle, Flux (metallurgy), 13. Climate action, Climatology, Spatial ecology, Mixing ratio, Environmental science, Boundary value problem, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: Atmospheric inversion models have the potential to quantify CO2 fluxes at regional, sub-continental scales by taking advantage of near-surface CO2 mixing ratio observations collected in areas with high flux variability. This study presents results from a series of regional geostatistical inverse models (GIM) over North America for 2004, and uses them as the basis for an inter-comparison to other inversion studies and estimates from biospheric models collected through the North American Carbon Program Regional and Continental Interim Synthesis. Because the GIM approach does not require explicit prior flux estimates and resolves fluxes at fine spatiotemporal scales (i.e. 1° × 1°, 3-hourly in this study), it avoids temporal and spatial aggregation errors and allows for the recovery of realistic spatial patterns from the atmospheric data relative to previous inversion studies. Results from a GIM inversion using only available atmospheric observations and a fine-scale fossil fuel inventory were used to confirm the quality of the inventory and inversion setup. An inversion additionally including auxiliary variables from the North American Regional Reanalysis found inferred relationships with flux consistent with physiological understanding of the biospheric carbon cycle. Comparison of GIM results with bottom-up biospheric models showed stronger agreement during the growing relative to the dormant season, in part because most of the biospheric models do not fully represent agricultural land-management practices and the fate of both residual biomass and harvested products. Comparison to earlier inversion studies pointed to aggregation errors as a likely source of bias in previous sub-continental scale flux estimates, particularly for inversions that adjust fluxes at the coarsest scales and use atmospheric observations averaged over long periods. Finally, whereas the continental CO2 boundary conditions used in the GIM inversions have a minor impact on spatial patterns, they have a substantial impact on the continental carbon budget, with a difference of 0.8 PgC yr−1 in the total continental flux resulting from the use of two plausible sets of boundary CO2 mixing ratios. Overall, this inter-comparison study helps to assess the state of the science in estimating regional-scale CO2 fluxes, while pointing towards the path forward for improvements in future top-down and bottom-up modeling efforts.
Published: 2012
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19. Increased light-use efficiency in northern terrestrial ecosystems indicated by CO 2 and greening observations

Author: Xiaoying Shi, Shushi Peng, Anna M. Michalak, Iain Colin Prentice, Joshua B. Fisher, Ning Zeng, Daniel J. Hayes, Akihiko Ito, Philippe Ciais, Rebecca T. Thomas, Atul K. Jain, Jiafu Mao, Daniel M. Ricciuto, Hanqin Tian, Maoyi Huang, Benjamin Poulter, Christopher R. Schwalm, Heather Graven, Deborah N. Huntzinger, Imperial College London, ICOS-ATC (ICOS-ATC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), University of Maine, Pacific Northwest National Laboratory (PNNL), Northern Arizona University [Flagstaff], National Institute for Environmental Studies (NIES), Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Carnegie Observatories, Carnegie Institution for Science, Peking University [Beijing], Montana State University (MSU), Environmental Sciences Division [Oak Ridge], UT-Battelle, LLC-UT-Battelle, LLC, Shandong Agricultural University (SDAU), University of Maryland [College Park], University of Maryland System, AXA Research Fund, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Carnegie Institution for Science [Washington]
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, 01 natural sciences, Latitude, Carbon cycle, Greening, MD Multidisciplinary, ATMOSPHERIC CARBON-DIOXIDE, PROGRAM MULTISCALE SYNTHESIS, Meteorology & Atmospheric Sciences, Geosciences, Multidisciplinary, 0105 earth and related environmental sciences, MODEL INTERCOMPARISON PROJECT, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Carbon dioxide in Earth's atmosphere, Science & Technology, LAND-USE, Biosphere, Geology, Vegetation, 15. Life on land, SEASONAL AMPLITUDE, BIOSPHERE MODELS, TRENDS, CLIMATE, Geophysics, 13. Climate action, Climatology, Physical Sciences, General Earth and Planetary Sciences, Environmental science, Terrestrial ecosystem, VEGETATION, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, ELEVATED CO2, Seasonal cycle, 010606 plant biology & botany
Abstract: International audience; Observations show an increasing amplitude in the seasonal cycle of CO 2 (ASC) north of 45 ∘ N of 56 ± 9.8% over the last 50 years and an increase in vegetation greenness of 7.5-15% in high northern latitudes since the 1980s. However, the causes of these changes remain uncertain. Historical simulations from terrestrial biosphere models in the Multiscale Synthesis and Terrestrial Model Intercomparison Project are compared to the ASC and greenness observations, using the TM3 atmospheric transport model to translate surface fluxes into CO 2 concentrations. We find that the modeled change in ASC is too small but the mean greening trend is generally captured. Modeled increases in greenness are primarily driven by warming, whereas ASC changes are primarily driven by increasing CO 2. We suggest that increases in ecosystem-scale light use efficiency (LUE) have contributed to the observed ASC increase but are underestimated by current models. We highlight potential mechanisms that could increase modeled LUE.
Published: 2016
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20. Disentangling climatic and anthropogenic controls on global terrestrial evapotranspiration trends

Author: Benjamin Poulter, Wenting Fu, Altaf Arain, Willis Otieno Shem, Anna M. Michalak, Chaoqun Lu, Changhui Peng, Daniel J. Hayes, Qiuan Zhu, Weile Wang, Daniel M. Ricciuto, Zhenzhong Zeng, Maoyi Huang, Akihiko Ito, Philippe Ciais, Yaxing Wei, Elchin Jafarov, Peter E. Thornton, Christopher R. Schwalm, Robert E. Dickinson, Shushi Peng, Yongjiu Dai, Jiafu Mao, Atul K. Jain, Robert B. Cook, Kevin Schaefer, Deborah N. Huntzinger, Hanqin Tian, Anthony W. King, Kaicun Wang, Xiaoying Shi, Shilong Piao, Fang Zhao, Forrest M. Hoffman, Suo Huang, Mingquan Mu, Joshua B. Fisher, Ning Zeng, Zaichun Zhu, Nicholas C. Parazoo, Huimin Lei, Centre Hospitalier de l'Université de Montréal (CHUM), Université de Montréal (UdeM), Environmental Sciences Division [Oak Ridge], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], Graduate School of Geography, Clark University, Shandong Agricultural University (SDAU), School of Geography and Earth Sciences [Hamilton ON], McMaster University [Hamilton, Ontario], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Cyprus Oceanography Center, University of Cyprus (UCY), Climate Change Science Institute [Oak Ridge] (CCSI), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Montana State University (MSU), UT-Battelle, LLC, Soochow University, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Cyprus [Nicosia] (UCY), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Univeristy of Cyprus, and Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA)
Subjects: Canopy, Plant growth, 010504 meteorology & atmospheric sciences, ved/biology.organism_classification_rank.species, 0207 environmental engineering, 02 engineering and technology, 01 natural sciences, Shrub, Natural (archaeology), Evapotranspiration, Water cycle, 020701 environmental engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Transpiration, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Renewable Energy, Sustainability and the Environment, ved/biology, Public Health, Environmental and Occupational Health, 15. Life on land, 13. Climate action, Climatology, Environmental science, Physical geography, Factorial analysis
Abstract: We examined natural and anthropogenic controls on terrestrial evapotranspiration (ET) changes from 1982 to 2010 using multiple estimates from remote sensing-based datasets and process-oriented land surface models. A significant increasing trend of ET in each hemisphere was consistently revealed by observationally-constrained data and multi-model ensembles that considered historic natural and anthropogenic drivers. The climate impacts were simulated to determine the spatiotemporal variations in ET. Globally, rising CO2 ranked second in these models after the predominant climatic influences, and yielded decreasing trends in canopy transpiration and ET, especially for tropical forests and high-latitude shrub land. Increasing nitrogen deposition slightly amplified global ET via enhanced plant growth. Land-use-induced ET responses, albeit with substantial uncertainties across the factorial analysis, were minor globally, but pronounced locally, particularly over regions with intensive land-cover changes. Our study highlights the importance of employing multi-stream ET and ET-component estimates to quantify the strengthening anthropogenic fingerprint in the global hydrologic cycle.
Published: 2015
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21. The terrestrial biosphere as a net source of greenhouse gases to the atmosphere

Author: Marielle Saunois, Philippe Bousquet, Pierre Friedlingstein, Guangsheng Chen, Kevin R. Gurney, Anna M. Michalak, Chaoqun Lu, Shufen Pan, Stephen Sitch, Hanqin Tian, Deborah N. Huntzinger, Jia Yang, Christopher R. Schwalm, Philippe Ciais, Benjamin Poulter, Ronald G. Prinn, Lori Bruhwiler, Edward J. Dlugokencky, Steven C. Wofsy, Eri Saikawa, Bowen Zhang, Jerry M. Melillo, Josep G. Canadell, Massachusetts Institute of Technology. Center for Global Change Science, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Prinn, Ronald G, Auburn University (AU), Iowa State University (ISU), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Carnegie Observatories, Carnegie Institution for Science [Washington], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Emory University [Atlanta, GA], Northern Arizona University [Flagstaff], Arizona State University [Tempe] (ASU), University of Exeter, Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), Woods Hole Oceanographic Institution (WHOI), Montana State University (MSU), Massachusetts Institute of Technology (MIT), Harvard University [Cambridge], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Carnegie Institution for Science, and Harvard University
Subjects: Greenhouse Effect, Asia, 010504 meteorology & atmospheric sciences, Atmospheric carbon cycle, Nitrous Oxide, Climate change, Carbon dioxide equivalent, 010501 environmental sciences, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Global Warming, Methane, chemistry.chemical_compound, Greenhouse gas removal, Human Activities, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecosystem, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, Ecology, Atmosphere, Atmospheric methane, Agriculture, Nitrous oxide, 15. Life on land, Carbon Dioxide, chemistry, 13. Climate action, Greenhouse gas, Environmental science
Abstract: The terrestrial biosphere can release or absorb the greenhouse gases, carbon dioxide (CO[subscript 2]), methane (CH[subscript 4]) and nitrous oxide (N[subscript 2]O), and therefore has an important role in regulating atmospheric composition and climate. Anthropogenic activities such as land-use change, agriculture and waste management have altered terrestrial biogenic greenhouse gas fluxes, and the resulting increases in methane and nitrous oxide emissions in particular can contribute to climate change. The terrestrial biogenic fluxes of individual greenhouse gases have been studied extensively,but the net biogenic greenhouse gas balance resulting from anthropogenic activities and its effect on the climate system remains uncertain. Here we use bottom-up (inventory, statistical extrapolation of local flux measurements, and process-based modelling) and top-down (atmospheric inversions) approaches to quantify the global net biogenic greenhouse gas balance between 1981 and 2010 resulting from anthropogenic activities and its effect on the climate system. We find that the cumulative warming capacity of concurrent biogenic methane and nitrous oxide emissions is a factor of about two larger than the cooling effect resulting from the global land carbon dioxide uptake from 2001 to 2010. This results in a net positive cumulative impact of the three greenhouse gases on the planetary energy budget, with a best estimate (in petagrams of CO[subscript 2] equivalent per year) of 3.9 ± 3.8 (top down) and 5.4 ± 4.8 (bottom up) based on the GWP100 metric (global warming potential on a 100-year time horizon). Our findings suggest that a reduction in agricultural methane and nitrous oxide emissions, particularly in Southern Asia, may help mitigate climate change., United States. National Aeronautics and Space Administration (NASA Grant NNX08AL73G), United States. National Aeronautics and Space Administration (NASA Grant NNX14AO73G), United States. National Aeronautics and Space Administration (NASA Grant NNX10AU06G), United States. National Aeronautics and Space Administration (NASA Grant NNX11AD47G), United States. National Aeronautics and Space Administration (NASA Grant NNG04GM39C), National Science Foundation (U.S.) (NSF grant AGS 1243232), National Science Foundation (U.S.) (Grant AGS-1243220), National Science Foundation (U.S.) (NSF grant CNH1210360), United States. National Oceanic and Atmospheric Administration (NOAA Climate Program Office award NA13OAR4310059), Australian Climate Change Science Programme, National Science Foundation (U.S.) (NSF CAREER (AGS-0846358)), United States. National Aeronautics and Space Administration (NASA Upper Atmosphere Research Program AGAGE, grant NNX11AF17G)
Published: 2015
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22. Global land carbon sink response to temperature and precipitation varies with ENSO phase

Author: Weile Wang, Yaxing Wei, Deborah N. Huntzinger, Daniel M. Ricciuto, Xiaoying Shi, Anna M. Michalak, Chaoqun Lu, Atul K. Jain, Robert B. Cook, Christopher R. Schwalm, Yuanyuan Fang, Joshua B. Fisher, Daniel J. Hayes, Benjamin Poulter, Jia Yang, Bo Tao, Hanqin Tian, Joseph A. Berry, Nicholas C. Parazoo, Huimin Lei, Shushi Peng, Jiafu Mao, Shilong Piao, Akihiko Ito, Philippe Ciais, Maoyi Huang, Department of Chemistry [University of Houston], University of Houston, Carnegie Observatories, Carnegie Institution for Science [Washington], Northern Arizona University [Flagstaff], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], Montana State University (MSU), University of Oxford [Oxford], Cyprus Oceanography Center, University of Cyprus (UCY), National Institute for Environmental Studies (NIES), Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Auburn University (AU), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, California Institute of Technology (CALTECH), Environmental Sciences Division [Oak Ridge], UT-Battelle, LLC-UT-Battelle, LLC, Shandong Agricultural University (SDAU), Carnegie Institution for Science, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Oxford, and University of Cyprus [Nicosia] (UCY)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0106 biological sciences, 010504 meteorology & atmospheric sciences, Renewable Energy, Sustainability and the Environment, Public Health, Environmental and Occupational Health, Climate change, Carbon sink, chemistry.chemical_element, Carbon sequestration, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, El Niño Southern Oscillation, chemistry, 13. Climate action, Climatology, Phase (matter), Environmental science, Precipitation, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Carbon, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science
Abstract: International audience
Published: 2017
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23. Carbon cycle uncertainty in the Alaskan Arctic

Author: M. A. Arain, A. K. Sahoo, Philippe Ciais, Enrico Tomelleri, Walter C. Oechel, Daniel J. Hayes, Chris Huntingford, Deborah N. Huntzinger, David Price, Mark R. Lomas, Ning Zeng, Kevin Schaefer, Ian Baker, Carl C. Davidson, Atul K. Jain, R. Wania, Hans Verbeeck, Joe R. Melton, Hanqin Tian, Peter Levy, Benjamin Poulter, Bassil El-Masri, Charles D. Koven, Michael Dietze, Joshua B. Fisher, Anders Ahlström, Nicolas Viovy, Charles E. Miller, Jing M. Chen, Munish Sikka, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), San Diego State University (SDSU), Northern Arizona University [Flagstaff], Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Lund University [Lund], McMaster University [Hamilton, Ontario], Colorado State University [Fort Collins] (CSU), Department of Geography and Planning [University of Toronto], University of Toronto, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Boston University [Boston] (BU), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Centre for Ecology and Hydrology (CEH), University of Sheffield [Sheffield], Montana State University (MSU), Natural Resources Canada (NRCan), Princeton University, National Snow and Ice Data Center (NSIDC), University of Colorado [Boulder], Auburn University (AU), Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, Universiteit Gent = Ghent University (UGENT), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric and Oceanic Science [College Park] (AOSC), University of Maryland [College Park], University of Maryland System-University of Maryland System, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Universiteit Gent = Ghent University [Belgium] (UGENT), École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226
Subjects: 010504 meteorology & atmospheric sciences, WETLAND EXTENT, lcsh:Life, chemistry.chemical_element, Climate change, Atmospheric sciences, 01 natural sciences, GLOBAL VEGETATION MODEL, Atmospheric Sciences, ATMOSPHERIC INVERSIONS, Carbon cycle, 03 medical and health sciences, Meteorology and Climatology, lcsh:QH540-549.5, METHANE EMISSIONS, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, TERRESTRIAL BIOSPHERE, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, 030304 developmental biology, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, CLIMATE-CHANGE, lcsh:QE1-996.5, Primary production, Carbon sink, Soil carbon, 15. Life on land, PERMAFROST CARBON, lcsh:Geology, lcsh:QH501-531, TUNDRA ECOSYSTEMS, Arctic, chemistry, COMPARISON PROJECT WETCHIMP, 13. Climate action, Earth and Environmental Sciences, Climatology, Earth Sciences, Environmental science, lcsh:Ecology, Hydrology, PRESENT STATE, Ecosystem respiration, Carbon
Abstract: Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects – NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project) – we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (σ) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0 ± 9.2 kg C m−2), then gross primary production (GPP) (0.22 ± 0.50 kg C m−2 yr−1), ecosystem respiration (Re) (0.23 ± 0.38 kg C m−2 yr−1), net primary production (NPP) (0.14 ± 0.33 kg C m−2 yr−1), autotrophic respiration (Ra) (0.09 ± 0.20 kg C m−2 yr−1), heterotrophic respiration (Rh) (0.14 ± 0.20 kg C m−2 yr−1), net ecosystem exchange (NEE) (−0.01 ± 0.19 kg C m−2 yr−1), and CH4 flux (2.52 ± 4.02 g CH4 m−2 yr−1). There were no consistent spatial patterns in the larger Alaskan Arctic and boreal regional carbon stocks and fluxes, with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region.
Published: 2014
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24. The North American Carbon Program Multi-scale Synthesis and Terrestrial Model Intercomparison Project – Part 2: Environmental driver data

Author: Andrew R. Jacobson, Xiaoying Shi, Jiafu Mao, Wilfred M. Post, Kevin Schaefer, Anna M. Michalak, Chaoqun Lu, Christopher R. Schwalm, Shuguang Liu, Robert B. Cook, Deborah N. Huntzinger, Yaxing Wei, Hanqin Tian, Daniel M. Ricciuto, Nicolas Viovy, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Estimation, Land use, Meteorology, 010504 meteorology & atmospheric sciences, business.industry, Computer science, Data management, lcsh:QE1-996.5, Environmental resource management, Land cover, Oak Ridge National Laboratory, 15. Life on land, 010501 environmental sciences, 01 natural sciences, Environmental data, lcsh:Geology, 13. Climate action, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, business, Scale (map), Temporal scales, 0105 earth and related environmental sciences
Abstract: Ecosystems are important and dynamic components of the global carbon cycle, and terrestrial biospheric models (TBMs) are crucial tools in further understanding of how terrestrial carbon is stored and exchanged with the atmosphere across a variety of spatial and temporal scales. Improving TBM skills, and quantifying and reducing their estimation uncertainties, pose significant challenges. The Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) is a formal multi-scale and multi-model intercomparison effort set up to tackle these challenges. The MsTMIP protocol prescribes standardized environmental driver data that are shared among model teams to facilitate model–model and model–observation comparisons. This paper describes the global and North American environmental driver data sets prepared for the MsTMIP activity to both support their use in MsTMIP and make these data, along with the processes used in selecting/processing these data, accessible to a broader audience. Based on project needs and lessons learned from past model intercomparison activities, we compiled climate, atmospheric CO2 concentrations, nitrogen deposition, land use and land cover change (LULCC), C3 / C4 grasses fractions, major crops, phenology and soil data into a standard format for global (0.5° × 0.5° resolution) and regional (North American: 0.25° × 0.25° resolution) simulations. In order to meet the needs of MsTMIP, improvements were made to several of the original environmental data sets, by improving the quality, and/or changing their spatial and temporal coverage, and resolution. The resulting standardized model driver data sets are being used by over 20 different models participating in MsTMIP. The data are archived at the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC, http://daac.ornl.gov) to provide long-term data management and distribution.
Published: 2013
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25. Evaluation of continental carbon cycle simulations with North American flux tower observations

Author: Trevor F. Keenan, Ronald P. Neilson, Hans Verbeeck, Ian Baker, Benjamin Poulter, Daniel M. Ricciuto, Enrico Tomelleri, Hanqin Tian, Kenneth J. Davis, Philippe Ciais, Kevin Schaefer, Deborah N. Huntzinger, Beverly E. Law, Brett Raczka, Jingfeng Xiao, Wilfred M. Post, Nicolas Viovy, Andrew D. Richardson, PennState Meteorology Department, Pennsylvania State University (Penn State), Penn State System-Penn State System, Northern Arizona University [Flagstaff], Department of Botany and Plant Pathology, Oregon State University (OSU), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Organismic and Evolutionary Biology [Cambridge] (OEB), Harvard University, Institute for the Study of Earth, Oceans, and Space [Durham] (EOS), University of New Hampshire (UNH), Department of Atmospheric Science [Fort Collins], Colorado State University [Fort Collins] (CSU), ICOS-ATC (ICOS-ATC), Department of Forest Ecosystems & Society, Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Environmental Sciences Division [Oak Ridge], UT-Battelle, LLC-UT-Battelle, LLC, National Snow and Ice Data Center (NSIDC), University of Colorado [Boulder], Auburn University (AU), Department of Biogeochemical Integration [Jena], Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Universiteit Gent = Ghent University (UGENT), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Harvard University [Cambridge], and Universiteit Gent = Ghent University [Belgium] (UGENT)
Subjects: Biosphere model, 010504 meteorology & atmospheric sciences, Magnitude (mathematics), UNITED-STATES, flux towers, 01 natural sciences, Carbon cycle, terrestrial biosphere models, Flux (metallurgy), DIOXIDE EXCHANGE, carbon fluxes, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, COMPARING GLOBAL-MODELS, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecology, Empirical modelling, Primary production, Biosphere, ENERGY FLUXES, 04 agricultural and veterinary sciences, 15. Life on land, DECIDUOUS FOREST, BIOSPHERE MODEL, 13. Climate action, Earth and Environmental Sciences, ATMOSPHERE CO2 EXCHANGE, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Terrestrial ecosystem, model-data comparison, NET PRIMARY PRODUCTIVITY, INTERANNUAL VARIABILITY, ECOSYSTEM EXCHANGE
Abstract: Terrestrial biosphere models can help identify physical processes that control carbon dynamics, including land-atmosphere CO2 fluxes, and have great potential to predict the terrestrial ecosystem response to changing climate. The skill of models that provide continental-scale carbon flux estimates, however, remains largely untested. This paper evaluates the performance of continental-scale flux estimates from 17 models against observations from 36 North American flux towers. Fluxes extracted from regional model simulations were compared with co-located flux tower observations at monthly and annual time increments. Site-level model simulations were used to help interpret sources of the mismatch between the regional simulations and site-based observations. On average, the regional model runs overestimated the annual gross primary productivity (5%) and total respiration (15%), and they significantly underestimated the annual net carbon uptake (64%) during the time period 2000-2005. Comparison with site-level simulations implicated choices specific to regional model simulations as contributors to the gross flux biases, but not the net carbon uptake bias. The models performed the best at simulating carbon exchange at deciduous broadleaf sites, likely because a number of models used prescribed phenology to simulate seasonal fluxes. The models did not perform as well for crop, grass, and evergreen sites. The regional models matched the observations most closely in terms of seasonal correlation and seasonal magnitude of variation, but they have very little skill at interannual correlation and minimal skill at interannual magnitude of variability. The comparison of site vs. regional-level model runs demonstrated that (1) the interannual correlation is higher for site-level model runs, but the skill remains low; and (2) the underestimation of year-to-year variability for all fluxes is an inherent weakness of the models. The best-performing regional models that did not use flux tower calibration were CLM-CN, CASA-GFEDv2, and SIB3.1. Two flux tower calibrated, empirical models, EC-MOD and MOD17 broken vertical bar, performed as well as the best process-based models. This suggests that (1) empirical, calibrated models can perform as well as complex, process-based models and (2) combining process-based model structure with relevant constraining data could significantly improve model performance.
Published: 2013
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26. North American Carbon Program (NACP) regional interim synthesis: Terrestrial biospheric model intercomparison

Author: Wenping Yuan, Atul K. Jain, Robert B. Cook, Peter E. Thornton, Shuguang Liu, Enrico Tomelleri, Nicolas Viovy, Tristram O. West, Kenneth J. Davis, A. D. McGuire, Deborah N. Huntzinger, Ronald P. Neilson, Jingfeng Xiao, Ning Zeng, Anna M. Michalak, Daniel J. Hayes, Maosheng Zhao, Benjamin Poulter, Andrew R. Jacobson, Hanqin Tian, Jing M. Chen, Yaxing Wei, Wilfred M. Post, Christopher Potter, David Price, Brett Raczka, Ian Baker, Forrest M. Hoffman, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Ecology, Ecological Modeling, Biosphere, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, Atmospheric sciences, 01 natural sciences, Carbon cycle, 13. Climate action, Carbon source, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Ecosystem, Terrestrial ecosystem, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Carbon flux
Abstract: Understanding of carbon exchange between terrestrial ecosystems and the atmosphere can be improved through direct observations and experiments, as well as through modeling activities. Terrestrial biosphere models (TBMs) have become an integral tool for extrapolating local observations and understanding to much larger terrestrial regions. Although models vary in their specific goals and approaches, their central role within carbon cycle science is to provide a better understanding of the mechanisms currently controlling carbon exchange. Recently, the North American Carbon Program (NACP) organized several interim-synthesis activities to evaluate and inter-compare models and observations at local to continental scales for the years 2000-2005. Here, we compare the results from the TBMs collected as part of the regional and continental interim-synthesis (RCIS) activities. The primary objective of this work is to synthesize and compare the 19 participating TBMs to assess current understanding of the terrestrial carbon cycle in North America. Thus, the RCIS focuses on model simulations available from analyses that have been completed by ongoing NACP projects and other recently published studies. The TBM flux estimates are compared and evaluated over different spatial (1{sup o} x 1{sup o} and spatially aggregated to different regions) and temporal (monthly and annually) scales. The range inmore » model estimates of net ecosystem productivity (NEP) for North America is much narrower than estimates of productivity or respiration, with estimates of NEP varying between -0.7 and 2.2 PgC yr{sup -1}, while gross primary productivity and heterotrophic respiration vary between 12.2 and 32.9 PgC yr{sup -1} and 5.6 and 13.2 PgC yr{sup -1}, respectively. The range in estimates from the models appears to be driven by a combination of factors, including the representation of photosynthesis, the source and of environmental driver data and the temporal variability of those data, as well as whether nutrient limitation is considered in soil carbon decomposition. The disagreement in current estimates of carbon flux across North America, including whether North America is a net biospheric carbon source or sink, highlights the need for further analysis through the use of model runs following a common simulation protocol, in order to isolate the influences of model formulation, structure, and assumptions on flux estimates.« less
Published: 2012
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27. A framework for benchmarking land models

Author: Ying-Ping Wang, Markus Reichstein, Rosie A. Fisher, Xuhui Zhou, Iain Colin Prentice, James T. Randerson, Nuno Carvalhais, Deborah N. Huntzinger, Pierre Friedlingstein, Philippe Peylin, Christopher R. Schwalm, Miguel D. Mahecha, Jianyang Xia, William J. Riley, Philippe Ciais, Cédric Bacour, Dejun Li, Yiqi Luo, Shuli Niu, David M. Lawrence, Daniela Dalmonech, S. L. Piao, Gab Abramowitz, Sönke Zaehle, Joshua B. Fisher, Charles D. Koven, Richard J. Norby, Eleanor Blyth, C. D. Jones, Forrest M. Hoffman, Xuan Qi, Kathleen A. Hibbard, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Meteorology, Computer science, lcsh:Life, Climate change, Infant Stage, 010603 evolutionary biology, 01 natural sciences, Meteorology and Climatology, trace gas, Ecosystem model, biogeochemistry, lcsh:QH540-549.5, biophysics, Physical Sciences and Mathematics, atmosphere-biosphere interaction, ecosystem response, spatiotemporal analysis, benchmarking, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Measure (data warehouse), ecosystem modeling, business.industry, vegetation dynamics, Frame (networking), Environmental resource management, lcsh:QE1-996.5, Benchmarking, prediction, 15. Life on land, lcsh:Geology, lcsh:QH501-531, climate change, Work (electrical), 13. Climate action, climate feedback, Benchmark (computing), lcsh:Ecology, business, numerical model
Abstract: Land models, which have been developed by the modeling community in the past few decades to predict future states of ecosystems and climate, have to be critically evaluated for their performance skills of simulating ecosystem responses and feedback to climate change. Benchmarking is an emerging procedure to measure performance of models against a set of defined standards. This paper proposes a benchmarking framework for evaluation of land model performances and, meanwhile, highlights major challenges at this infant stage of benchmark analysis. The framework includes (1) targeted aspects of model performance to be evaluated, (2) a set of benchmarks as defined references to test model performance, (3) metrics to measure and compare performance skills among models so as to identify model strengths and deficiencies, and (4) model improvement. Land models are required to simulate exchange of water, energy, carbon and sometimes other trace gases between the atmosphere and land surface, and should be evaluated for their simulations of biophysical processes, biogeochemical cycles, and vegetation dynamics in response to climate change across broad temporal and spatial scales. Thus, one major challenge is to select and define a limited number of benchmarks to effectively evaluate land model performance. The second challenge is to develop metrics of measuring mismatches between models and benchmarks. The metrics may include (1) a priori thresholds of acceptable model performance and (2) a scoring system to combine data–model mismatches for various processes at different temporal and spatial scales. The benchmark analyses should identify clues of weak model performance to guide future development, thus enabling improved predictions of future states of ecosystems and climate. The near-future research effort should be on development of a set of widely acceptable benchmarks that can be used to objectively, effectively, and reliably evaluate fundamental properties of land models to improve their prediction performance skills.
Published: 2012
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28. Decadal trends in the seasonal-cycle amplitude of terrestrial CO2 exchange resulting from the ensemble of terrestrial biosphere models

Author: Xiaoying Shi, Fang Zhao, Joshua B. Fisher, Kevin Schaefer, Nicholas C. Parazoo, Suo Huang, Huimin Lei, Jia Yang, Akihiko Ito, Philippe Ciais, Benjamin Poulter, Motoko Inatomi, Bo Tao, Ning Zeng, M. Altaf Arain, Weile Wang, W. Mac Post, Jiafu Mao, Deborah N. Huntzinger, Shushi Peng, Christopher R. Schwalm, Atul K. Jain, Robert B. Cook, Anna M. Michalak, Chaoqun Lu, Changhui Peng, Daniel J. Hayes, Daniel M. Ricciuto, Hanqin Tian, Maoyi Huang, Anthony W. King, and Yaxing Wei
Subjects: 0106 biological sciences, Atmospheric Science, Carbon dioxide in Earth's atmosphere, 010504 meteorology & atmospheric sciences, Biosphere, Climate change, 15. Life on land, Seasonality, medicine.disease, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, 13. Climate action, Climatology, medicine, Environmental science, Land use, land-use change and forestry, Terrestrial ecosystem, Ecosystem, 0105 earth and related environmental sciences
Abstract: The seasonal-cycle amplitude (SCA) of the atmosphere–ecosystem carbon dioxide (CO 2 ) exchange rate is a useful metric of the responsiveness of the terrestrial biosphere to environmental variations. It is unclear, however, what underlying mechanisms are responsible for the observed increasing trend of SCA in atmospheric CO 2 concentration. Using output data from the Multi-scale Terrestrial Model Intercomparison Project (MsTMIP), we investigated how well the SCA of atmosphere–ecosystem CO 2 exchange was simulated with 15 contemporary terrestrial ecosystem models during the period 1901–2010. Also, we made attempt to evaluate the contributions of potential mechanisms such as atmospheric CO 2 , climate, land-use, and nitrogen deposition, through factorial experiments using different combinations of forcing data. Under contemporary conditions, the simulated global-scale SCA of the cumulative net ecosystem carbon flux of most models was comparable in magnitude with the SCA of atmospheric CO 2 concentrations. Results from factorial simulation experiments showed that elevated atmospheric CO 2 exerted a strong influence on the seasonality amplification. When the model considered not only climate change but also land-use and atmospheric CO 2 changes, the majority of the models showed amplification trends of the SCAs of photosynthesis, respiration, and net ecosystem production (+0.19 % to +0.50 % yr −1 ). In the case of land-use change, it was difficult to separate the contribution of agricultural management to SCA because of inadequacies in both the data and models. The simulated amplification of SCA was approximately consistent with the observational evidence of the SCA in atmospheric CO 2 concentrations. Large inter-model differences remained, however, in the simulated global tendencies and spatial patterns of CO 2 exchanges. Further studies are required to identify a consistent explanation for the simulated and observed amplification trends, including their underlying mechanisms. Nevertheless, this study implied that monitoring of ecosystem seasonality would provide useful insights concerning ecosystem dynamics. Keywords: atmospheric carbon dioxide, carbon cycle, climate change, land-use change, seasonal cycle, terrestrial ecosystem (Published: 12 May 2016) Citation: Tellus B 2016, 68, 28968, http://dx.doi.org/10.3402/tellusb.v68.28968
Published: 2016
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29. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions

Author: Benjamin Poulter, Huimin Lei, Anna M. Michalak, Chaoqun Lu, Kamaljit Banger, Hanqin Tian, Wei Ren, Daniel J. Hayes, Bowen Zhang, Akihiko Ito, Philippe Ciais, Shushi Peng, Jia Yang, Yaxing Wei, Shufen Pan, Jiafu Mao, Weile Wang, Deborah N. Huntzinger, Bo Tao, Christopher R. Schwalm, Kevin Schaefer, Ning Zeng, Daniel M. Ricciuto, Xiaoying Shi, Qichun Yang, Wilfred M. Post, Atul K. Jain, Robert B. Cook, Maoyi Huang, Auburn University (AU), Northern Arizona University [Flagstaff], Carnegie Institution for Science [Washington], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Institute for Environmental Studies (NIES), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Tsinghua University [Beijing] (THU), Montana State University (MSU), State Key Lab of Advanced Optical Communication Systems and Networks (Shanghai Jiao Tong University), Environmental Sciences Division [Oak Ridge], UT-Battelle, LLC-UT-Battelle, LLC, Carnegie Institution for Science, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Climate change, Soil science, Biogeosciences, Atmospheric sciences, 01 natural sciences, Soils/Pedology, Carbon cycle, Biogeochemical Kinetics and Reaction Modeling, Global Change from Geodesy, Oceanography: Biological and Chemical, heterotrophic respiration (Rh), Paleoceanography, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Environmental Chemistry, Geodesy and Gravity, Global Change, soil carbon dynamics model, uncertainty, Research Articles, 0105 earth and related environmental sciences, General Environmental Science, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Carbon dioxide in Earth's atmosphere, Soil organic matter, Biosphere, 04 agricultural and veterinary sciences, Soil carbon, Biogeochemistry, 15. Life on land, Climate Impact, soil organic carbon (SOC), 13. Climate action, 040103 agronomy & agriculture, Soils, 0401 agriculture, forestry, and fisheries, Soil horizon, Environmental science, Terrestrial ecosystem, Hydrology, mean residence time (MRT), Cryosphere, belowground processes, Biogeochemical Cycles, Processes, and Modeling, Impacts of Global Change, Natural Hazards, Research Article
Abstract: Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land‐atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO2) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process‐based modeling. However, these estimates are highly uncertain, and identifying major driving forces controlling soil C dynamics remains a key research challenge. This study has compiled century‐long (1901–2010) estimates of SOC storage and heterotrophic respiration (Rh) from 10 terrestrial biosphere models (TBMs) in the Multi‐scale Synthesis and Terrestrial Model Intercomparison Project and two observation‐based data sets. The 10 TBM ensemble shows that global SOC estimate ranges from 425 to 2111 Pg C (1 Pg = 1015 g) with a median value of 1158 Pg C in 2010. The models estimate a broad range of Rh from 35 to 69 Pg C yr−1 with a median value of 51 Pg C yr−1 during 2001–2010. The largest uncertainty in SOC stocks exists in the 40–65°N latitude whereas the largest cross‐model divergence in Rh are in the tropics. The modeled SOC change during 1901–2010 ranges from −70 Pg C to 86 Pg C, but in some models the SOC change has a different sign from the change of total C stock, implying very different contribution of vegetation and soil pools in determining the terrestrial C budget among models. The model ensemble‐estimated mean residence time of SOC shows a reduction of 3.4 years over the past century, which accelerate C cycling through the land biosphere. All the models agreed that climate and land use changes decreased SOC stocks, while elevated atmospheric CO2 and nitrogen deposition over intact ecosystems increased SOC stocks—even though the responses varied significantly among models. Model representations of temperature and moisture sensitivity, nutrient limitation, and land use partially explain the divergent estimates of global SOC stocks and soil C fluxes in this study. In addition, a major source of systematic error in model estimations relates to nonmodeled SOC storage in wetlands and peatlands, as well as to old C storage in deep soil layers., Key Points Simulated historical (1901–2010) SOC dynamics vary largely among modelsTen TBMs agree that climate and land use change have reduced SOC stocksRising CO2 and N deposition are prone to increase SOC with varying magnitudes
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29 results on '"Deborah N. Huntzinger"'

1. Linking global terrestrial CO2 fluxes and environmental drivers: inferences from the Orbiting Carbon Observatory 2 satellite and terrestrial biospheric models

2. Five years of variability in the global carbon cycle: comparing an estimate from the Orbiting Carbon Observatory-2 and process-based models

3. Modeling suggests fossil fuel emissions have been driving increased land carbon uptake since the turn of the 20th Century

4. Linking global terrestrial CO2 fluxes and environmental drivers using OCO-2 and a geostatistical inverse model

5. Enhanced peak growth of global vegetation and its key mechanisms

6. Global patterns of drought recovery

7. Reduced North American terrestrial primary productivity linked to anomalous Arctic warming

8. Climate-driven risks to the climate mitigation potential of forests

9. Field-experiment constraints on the enhancement of the terrestrial carbon sink by CO2 fertilization

10. Global vegetation biomass production efficiency constrained by models and observations

11. Uncertainty analysis of terrestrial net primary productivity and net biome productivity in China during 1901-2005

12. Technical note: 3-hourly temporal downscaling of monthly global terrestrial biosphere model net ecosystem exchange

13. Accelerating rates of Arctic carbon cycling revealed by long-term atmospheric CO 2 measurements

14. Missing pieces to modeling the Arctic-Boreal puzzle

15. Response of Water Use Efficiency to Global Environmental Change Based on Output From Terrestrial Biosphere Models

16. The North American Carbon Program Multi-Scale Synthesis and Terrestrial Model Intercomparison Project – Part 1: Overview and experimental design

17. Uncertainty in the response of terrestrial carbon sink to environmental drivers undermines carbon-climate feedback predictions

18. North American CO2 exchange: inter-comparison of modeled estimates with results from a fine-scale atmospheric inversion

19. Increased light-use efficiency in northern terrestrial ecosystems indicated by CO 2 and greening observations

20. Disentangling climatic and anthropogenic controls on global terrestrial evapotranspiration trends

21. The terrestrial biosphere as a net source of greenhouse gases to the atmosphere

22. Global land carbon sink response to temperature and precipitation varies with ENSO phase

23. Carbon cycle uncertainty in the Alaskan Arctic

24. The North American Carbon Program Multi-scale Synthesis and Terrestrial Model Intercomparison Project – Part 2: Environmental driver data

25. Evaluation of continental carbon cycle simulations with North American flux tower observations

26. North American Carbon Program (NACP) regional interim synthesis: Terrestrial biospheric model intercomparison

27. A framework for benchmarking land models

28. Decadal trends in the seasonal-cycle amplitude of terrestrial CO2 exchange resulting from the ensemble of terrestrial biosphere models

29. Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions

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29 results on '"Deborah N. Huntzinger"'

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