34 results on '"Judson W. Partin"'
Search Results
2. Pronounced centennial-scale Atlantic Ocean climate variability correlated with Western Hemisphere hydroclimate
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Kaustubh Thirumalai, Terrence M. Quinn, Yuko Okumura, Julie N. Richey, Judson W. Partin, Richard Z. Poore, and Eduardo Moreno-Chamarro
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Science - Abstract
Knowledge of surface-ocean circulation in the Atlantic over the late Holocene is incomplete. Here, the authors show that Atlantic Ocean surface-circulation varied in concert with Western Hemisphere rainfall anomalies on centennial timescales and that this link played an essential role during the Little Ice Age.
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- 2018
- Full Text
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3. Unraveling forced responses of extreme El Niño variability over the Holocene
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Allison E. Lawman, Pedro N. Di Nezio, Judson W. Partin, Sylvia G. Dee, Kaustubh Thirumalai, and Terrence M. Quinn
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Multidisciplinary - Abstract
Uncertainty surrounding the future response of El Niño–Southern Oscillation (ENSO) variability to anthropogenic warming necessitates the study of past ENSO sensitivity to substantial climate forcings over geological history. Here, we focus on the Holocene epoch and show that ENSO amplitude and frequency intensified over this period, driven by an increase in extreme El Niño events. Our study combines new climate model simulations, advances in coral proxy system modeling, and coral proxy data from the central tropical Pacific. Although the model diverges from the observed coral data regarding the exact magnitude of change, both indicate that modern ENSO variance eclipsed paleo-estimates over the Holocene, albeit against the backdrop of wide-ranging natural variability. Toward further constraining paleo-ENSO, our work underscores the need for multimodel investigations of additional Holocene intervals alongside more coral data from periods with larger climate forcing. Our findings implicate extreme El Niño events as an important rectifier of mean ENSO intensity.
- Published
- 2022
4. The Iso2k database: a global compilation of paleo-δ18O and δ2H records to aid understanding of Common Era climate
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Jessica L. Conroy, Kristine L. DeLong, Trevor J. Porter, Alyssa R. Atwood, Elizabeth K. Thomas, Diane M. Thompson, Hussein R. Sayani, Jonathan J. Tyler, Emilie Pauline Dassié, S. R. Managave, Matt J. Fischer, Samantha Stevenson, Nerilie J. Abram, Olga V. Churakova (Sidorova), Bronwen Konecky, Georgina Falster, Thomas Opel, Judson W. Partin, Lucien von Gunten, Lukas Jonkers, Nicholas P. McKay, Laia Comas-Bru, Zoltán Kern, Darrell S. Kaufman, Belen Martrat, Matthew Jones, Guillaume Leduc, and Anais Orsi
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Database ,Environmental change ,Stable isotope ratio ,δ18O ,Glacier ,15. Life on land ,010502 geochemistry & geophysics ,computer.software_genre ,01 natural sciences ,Proxy (climate) ,Metadata ,Data assimilation ,13. Climate action ,Loess ,General Earth and Planetary Sciences ,14. Life underwater ,computer ,Geology ,0105 earth and related environmental sciences - Abstract
Reconstructions of global hydroclimate during the Common Era (CE; the past ∼2000 years) are important for providing context for current and future global environmental change. Stable isotope ratios in water are quantitative indicators of hydroclimate on regional to global scales, and these signals are encoded in a wide range of natural geologic archives. Here we present the Iso2k database, a global compilation of previously published datasets from a variety of natural archives that record the stable oxygen (δ18O) or hydrogen (δ2H) isotopic compositions of environmental waters, which reflect hydroclimate changes over the CE. The Iso2k database contains 759 isotope records from the terrestrial and marine realms, including glacier and ground ice (210); speleothems (68); corals, sclerosponges, and mollusks (143); wood (81); lake sediments and other terrestrial sediments (e.g., loess) (158); and marine sediments (99). Individual datasets have temporal resolutions ranging from sub-annual to centennial and include chronological data where available. A fundamental feature of the database is its comprehensive metadata, which will assist both experts and nonexperts in the interpretation of each record and in data synthesis. Key metadata fields have standardized vocabularies to facilitate comparisons across diverse archives and with climate-model-simulated fields. This is the first global-scale collection of water isotope proxy records from multiple types of geological and biological archives. It is suitable for evaluating hydroclimate processes through time and space using large-scale synthesis, model–data intercomparison and (paleo)data assimilation. The Iso2k database is available for download at https://doi.org/10.25921/57j8-vs18 (Konecky and McKay, 2020) and is also accessible via the NOAA/WDS Paleo Data landing page: https://www.ncdc.noaa.gov/paleo/study/29593 (last access: 30 July 2020).
- Published
- 2020
5. Constraining speleothem oxygen isotope disequilibrium driven by rapid CO2 degassing and calcite precipitation: Insights from monitoring and modeling
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Daniel O. Breecker, Alexandra L. Noronha, Judson W. Partin, Jay L. Banner, Mark W. Moore, Peter E. Carlson, John W. Jenson, Kaylyn K. Bautista, and Michael Deininger
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Calcite ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,δ18O ,Speleothem ,Mineralogy ,Stalagmite ,010502 geochemistry & geophysics ,01 natural sciences ,Isotopes of oxygen ,chemistry.chemical_compound ,Isotope fractionation ,chemistry ,Cave ,Geochemistry and Petrology ,Paleoclimatology ,Environmental science ,0105 earth and related environmental sciences - Abstract
Oxygen isotopes are the most commonly applied speleothem proxy for reconstructing Quaternary changes in precipitation and/or temperature. These interpretations are either limited to qualitative wetting and drying trends or rely on theoretical, experimental and/or empirical equilibrium isotope fractionation factors for more quantitative constraints. These various fractionation factors have similar temperature sensitivities, but their absolute values differ, and cave calcite does not appear to generally precipitate in isotopic equilibrium with its drip water. Rapid CO2 degassing paired with calcite precipitation, both occurring under disequilibrium conditions, are a set of mechanisms commonly invoked to explain offsets between observed and equilibrium isotopic fractionation between cave calcites and drip waters. However, the relevance of these disequilibrium mechanisms to speleothem records remains unresolved. Here, we compare measured δ18O values of modern speleothem calcite from a tropical cave in Guam to calcite δ18O values predicted by a modified version of the ISOLUTION proxy system model. This extends the global comparison of cave drip water and modern calcite δ18O values to higher temperatures. We initialize the model using contemporaneous measurements of drip water (δ18O values, [Ca+], and pH), and cave air (CO2, and T) from four drip sites over 3.5 years of monitoring in the cave. Through this comparison, we show that for a slow drip-rate site, ventilation-driven CO2 degassing can explain seasonal variations in calcite oxygen isotope composition. At faster-dripping sites in this cave, the seasonal effect is limited. At these sites, the DIC reservoir is replenished by new drips faster than its isotopic composition can be modified by degassing CO2 and calcite precipitation, whether occurring each is occurring as an equilibrium or kinetic process. For the slow drip rate site, however, this is the first observation of cave air CO2 variations exerting a control on cave calcite oxygen isotope values. The confirmation of ventilation-driven processes controlling oxygen isotope values at a slow-drip site advances the process-based understanding of stalagmite formation that is required to move beyond the wetter-or-drier paradigm and make quantitative interpretations of speleothem oxygen isotope records.
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- 2020
6. Rainfall variations in central Indo-Pacific over the past 2,700 y
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Chuan-Chou Shen, Ola Kwiecien, Helmut Duerrast, Yu Chen Chou, Yanjun Cai, Barbara Wohlfarth, Akkaneewut Chabangborn, Judson W. Partin, Wenju Cai, Sakonvan Chawchai, Ludvig Löwemark, Hai Cheng, Chung-Che Wu, R. Lawrence Edwards, Liangcheng Tan, Huang Hsiung Hsu, Zhengguo Shi, Yongli Gao, and Sebastian F. M. Breitenbach
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010504 meteorology & atmospheric sciences ,rainfall ,F700 ,F800 ,Stalagmite ,Forcing (mathematics) ,F600 ,010502 geochemistry & geophysics ,01 natural sciences ,Earth, Atmospheric, and Planetary Sciences ,Centennial ,central Indo-Pacific ,stalagmite ,ITCZ ,0105 earth and related environmental sciences ,geography ,Multidisciplinary ,geography.geographical_feature_category ,Intertropical Convergence Zone ,Tropics ,13. Climate action ,Climatology ,Physical Sciences ,Period (geology) ,Walker circulation ,ENSO ,Geology ,Indo-Pacific - Abstract
Significance We present a high-resolution, replicated speleothem δ18O record from Klang Cave in southern Thailand that characterizes rainfall variation in NCIP over the past 2,700 y. This record reveals notable dry climate conditions during the current and past warm periods, similar to the observations in SCIP, which resemble enhanced El Niño-like conditions. Using a newly developed ITCZ shift index, we find a southward shifted ITCZ during the early MWP and the CWP. Our results suggest that detecting changes in rainfall due to anthropogenic forcing still remains indistinguishable from natural variability in the northern tropics., Tropical rainfall variability is closely linked to meridional shifts of the Intertropical Convergence Zone (ITCZ) and zonal movements of the Walker circulation. The characteristics and mechanisms of tropical rainfall variations on centennial to decadal scales are, however, still unclear. Here, we reconstruct a replicated stalagmite-based 2,700-y-long, continuous record of rainfall for the deeply convective northern central Indo-Pacific (NCIP) region. Our record reveals decreasing rainfall in the NCIP over the past 2,700 y, similar to other records from the northern tropics. Notable centennial- to decadal-scale dry climate episodes occurred in both the NCIP and the southern central Indo-Pacific (SCIP) during the 20th century [Current Warm Period (CWP)] and the Medieval Warm Period (MWP), resembling enhanced El Niño-like conditions. Further, we developed a 2,000-y-long ITCZ shift index record that supports an overall southward ITCZ shift in the central Indo-Pacific and indicates southward mean ITCZ positions during the early MWP and the CWP. As a result, the drying trend since the 20th century in the northern tropics is similar to that observed during the past warm period, suggesting that a possible anthropogenic forcing of rainfall remains indistinguishable from natural variability.
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- 2019
7. Controls on the Isotopic Composition of Precipitation in the South‐Central United States
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Judson W. Partin, Chijun Sun, and Timothy M. Shanahan
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Atmospheric Science ,Mesoscale convective system ,Geophysics ,Space and Planetary Science ,Paleoclimatology ,Earth and Planetary Sciences (miscellaneous) ,medicine ,Environmental science ,Precipitation ,Seasonality ,Atmospheric sciences ,medicine.disease ,Isotopic composition - Published
- 2019
8. Considerations for <scp> Globigerinoides ruber </scp> (White and Pink) Paleoceanography: Comprehensive Insights From a Long‐Running Sediment Trap
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Julie N. Richey, Kaustubh Thirumalai, Caitlin E. Reynolds, Judson W. Partin, Deborah Khider, and Terrence M. Quinn
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Atmospheric Science ,White (horse) ,Oceanography ,biology ,Paleoceanography ,Paleontology ,Environmental science ,Sediment trap (geology) ,biology.organism_classification ,Globigerinoides - Published
- 2019
9. Isotopic and geochemical assessment of the sensitivity of groundwater resources of Guam, Mariana Islands, to intra- and inter-annual variations in hydroclimate
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Corinne I. Wong, N.H. van Oort, Judson W. Partin, Jay L. Banner, Mark A. Lander, Stephen B. Gingerich, Kaylyn K. Bautista, John W. Jenson, Ben Hardt, and L. K. Beal
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Hydrology ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,δ18O ,Lens (hydrology) ,0207 environmental engineering ,Aquifer ,02 engineering and technology ,Groundwater recharge ,01 natural sciences ,Vadose zone ,Environmental science ,Spatial variability ,020701 environmental engineering ,Groundwater ,0105 earth and related environmental sciences ,Water Science and Technology ,Geochemical modeling - Abstract
Assessing the sensitivity of groundwater systems to hydroclimate variability is critical to sustainable management of the water resources of Guam, US territory. We assess spatial and temporal variability of isotopic and geochemical compositions of vadose and phreatic groundwater sampled from cave drip sites and production wells, respectively, to better understand the vulnerability of the freshwater lens on Guam to variability in hydroclimate. We independently evaluate the existing conceptual model of the Northern Guam Lens Aquifer that is largely based on physical, as opposed to geochemical, observations. Sampling was conducted from 2008 to 2015, over which rainfall gradually increased. Major ion geochemistry and Sr isotope values of groundwater show varying influence from soil, limestone bedrock, and seawater. Geochemical modeling that can explain spatial variability in groundwater Na+ and Mg2+ concentrations and Sr/Ca and 87Sr/86Sr values indicates that groundwater compositions are dominantly controlled by mixing of freshwater with seawater and water-rock interaction. Differences between amount-weighted annual average precipitation δ18O values and groundwater δ18O values indicate a recharge bias toward the wet season, consistent with other tropical carbonate island aquifer settings. Intra- and inter-annual variations in Na+ concentrations and δ18O values in groundwater reflect sensitivity of recharge to seasonal variations in rainfall amount and changes in annual rainfall amounts. Our results indicate the influence of multiple modes of recharge on groundwater compositions and spatial variability in the sensitivity of groundwater to seawater mixing. This sensitivity of the freshwater lens points to the vulnerability of groundwater resources to changes in recharge associated with climate, land-use change, and increases in population.
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- 2019
10. Abrupt Southern Great Plains thunderstorm shifts linked to glacial climate variability
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Audrey L. Housson, Chuan-Chou Shen, E. Brendan Roark, Judson W. Partin, C. Lorraine McChesney, Tsai-Luen Yu, Stephen Van Kampen-Lewis, Kaustubh Thirumalai, Courtney Schumacher, Oruç Baykara, Christopher R. Maupin, and Kemble White
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Strongly coupled ,geography ,Stalactite ,geography.geographical_feature_category ,Storm ,climatology ,simulation ,Texas ,Isotopes of oxygen ,climate variation ,United States ,Climatology ,Thunderstorm ,General Earth and Planetary Sciences ,Climate model ,Glacial period ,midlatitude environment ,climate modeling ,thunderstorm - Abstract
Thunderstorms in the Southern Great Plains of the United States are among the strongest on Earth and have been shown to be increasing in intensity and frequency during recent years. Assessing changes in storm characteristics under different climate scenarios, however, remains highly uncertain due to limitations in climate model physics. We analyse oxygen isotopes from Texas stalactites from 30–50 thousand years ago to assess past changes in thunderstorm size and duration using a modern radar-based calibration for the region. Storm regimes shift from weakly to strongly organized on millennial timescales and are coincident with well-known abrupt climate shifts during the last glacial period. Modern-day synoptic analysis suggests that thunderstorm organization in the Southern Great Plains is strongly coupled to changes in large-scale wind and moisture patterns. These changes in the large-scale circulation may be used to assess future predictions and palaeo-simulations of mid-latitude thunderstorm climatologies. Thunderstorm activity in the Southern Great Plains was closely coupled to abrupt climate shifts during the last glacial period, according to an analysis of oxygen isotopes in modern rainfall and ancient speleothems from Texas.
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- 2021
11. Methane, Monsoons, and Modulation of Millennial‐Scale Climate
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Steven C. Clemens, Judson W. Partin, and Kaustubh Thirumalai
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Orbital forcing ,Atmospheric methane ,Speleothem ,Climate change ,010502 geochemistry & geophysics ,Monsoon ,01 natural sciences ,Methane ,Latitude ,chemistry.chemical_compound ,Geophysics ,chemistry ,Climatology ,General Earth and Planetary Sciences ,Environmental science ,East Asian Monsoon ,0105 earth and related environmental sciences - Abstract
Earths orbital geometry exerts a profound influence on climate by regulating changes in incoming solar radiation. Superimposed on orbitally-paced climate change, Pleistocene records reveal substantial millennial-scale variability characterized by trends, tipping points, and rapid swings. However, the extent to which orbital forcing modulates the amplitude and timing of these millennial variations is unclear. Here we isolate the magnitude of millennial-scale variability (MMV) in two well-dated records, both linked to precession cycles (19,000-23,000-year periodicity): atmospheric methane and Chinese speleothem δ¹⁸O, where the latter is commonly interpreted as a proxy for Asian monsoon intensity. At the millennial timescale (1,000-10,000 years), we find a fundamental decoupling wherein precession directly modulates the MMV of methane but not that of speleothem-δ¹⁸O. We hypothesize that mid-to-high latitude insolation modulates the MMV of atmospheric methane, but feedbacks internal to the Earth-climate system modulate the strength of millennial-scale monsoonal circulation.
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- 2020
12. Extended Cave Drip Water Time Series Captures the 2015–2016 El Niño in Northern Borneo
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A. Landry Bennett, Andrew Alek Tuen, Kim M. Cobb, Jenny Malang, Shelby A Ellis, Judson W. Partin, J. W. Moerman, and Hein Gerstner
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geography ,Series (stratigraphy) ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Tropical rainfall ,010502 geochemistry & geophysics ,01 natural sciences ,Isotopes of oxygen ,Geophysics ,El Niño Southern Oscillation ,Oceanography ,Cave ,General Earth and Planetary Sciences ,Geology ,0105 earth and related environmental sciences - Published
- 2020
13. Correlation-based interpretations of paleoclimate data – where statistics meet past climates
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Jun Hu, Julien Emile-Geay, and Judson W. Partin
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Future studies ,010504 meteorology & atmospheric sciences ,Autocorrelation ,010502 geochemistry & geophysics ,01 natural sciences ,Proxy (climate) ,Correlation ,Geophysics ,13. Climate action ,Space and Planetary Science ,Geochemistry and Petrology ,Paleoclimatology ,Correlation analysis ,Statistics ,Earth and Planetary Sciences (miscellaneous) ,Spurious relationship ,Geology ,0105 earth and related environmental sciences - Abstract
Correlation analysis is omnipresent in paleoclimatology, and often serves to support the proposed climatic interpretation of a given proxy record. However, this analysis presents several statistical challenges, each of which is sufficient to nullify the interpretation: the loss of degrees of freedom due to serial correlation, the test multiplicity problem in connection with a climate field, and the presence of age uncertainties. While these issues have long been known to statisticians, they are not widely appreciated by the wider paleoclimate community; yet they can have a first-order impact on scientific conclusions. Here we use three examples from the recent paleoclimate literature to highlight how spurious correlations affect the published interpretations of paleoclimate proxies, and suggest that future studies should address these issues to strengthen their conclusions. In some cases, correlations that were previously claimed to be significant are found insignificant, thereby challenging published interpretations. In other cases, minor adjustments can be made to safeguard against these concerns. Because such problems arise so commonly with paleoclimate data, we provide open-source code to address them. Ultimately, we conclude that statistics alone cannot ground-truth a proxy, and recommend establishing a mechanistic understanding of a proxy signal as a sounder basis for interpretation.
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- 2017
14. Trade winds drive pronounced seasonality in carbonate chemistry in a tropical Western Pacific island cave-Implications for speleothem paleoclimatology
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John W. Jenson, Eric W. James, B. F. Hardt, Jay L. Banner, Alexandra L. Noronha, Kaylyn K. Bautista, Mark A. Lander, and Judson W. Partin
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Calcite ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Speleothem ,Stalagmite ,Seasonality ,010502 geochemistry & geophysics ,Karst ,medicine.disease ,01 natural sciences ,chemistry.chemical_compound ,Geophysics ,Oceanography ,chemistry ,Cave ,Geochemistry and Petrology ,Paleoclimatology ,medicine ,Carbonate ,Geology ,0105 earth and related environmental sciences - Abstract
Carbon dioxide concentrations in caves are a primary driver of rates of carbonate dissolution and precipitation, exerting strong control on speleothem growth rate and geochemistry. Long-term cave monitoring studies in mid-latitude caves have observed seasonal variability in cave pCO2, whereby airflow is driven by temperature contrasts between the surface and subsurface. In tropical settings, where diurnal temperature cycles are larger than seasonal temperature cycles, it is has been proposed caves will ventilate on daily timescales, preventing cave pCO2 from increasing substantially above atmospheric pCO2. By contrast, the relatively small temperature difference between the surface and subsurface may be insufficient to drive complete ventilation of tropical caves. Here we present results of an 8-year cave monitoring study, including observations of cave pCO2 and carbonate chemistry, at Jinapsan Cave, Guam (13.4°N, 144.5°E). We find that cave pCO2 in Jinapsan Cave is both relatively high and strongly seasonal, with cave pCO2 ranging from 500 - 5000 ppm. The seasonality of cave pCO2 cannot be explained by temperature contrasts, instead we find evidence that seasonal trade winds drive cave ventilation and modulate cave pCO2. Calcite deposition rates at seven drip sites in Jinapsan Cave are shown to be seasonally variable, demonstrating that speleothem growth rates in Jinapsan Cave are strongly affected by seasonal variations in cave pCO2. These results highlight the importance that advection can have on cave ventilation processes and carbonate chemistry. Seasonality in carbonate chemistry and calcite deposition in this cave effect the interpretation of speleothem-based paleoclimate records. This article is protected by copyright. All rights reserved.
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- 2017
15. PaCTS 1.0: a crowdsourced reporting standard for paleoclimate data
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Maxime Debret, Emilie Pauline Dassié, Varun Ratnakar, M. P. Erb, Valdir F. Novello, M. Kienast, Walter Finsinger, Timothy T. Barrows, J.J. Williams, A. Frappier, Natalie Kehrwald, Nicolas Gauthier, F. Schwanck, Laia Comas-Bru, Darrell S. Kaufman, Daniel Fortier, Lucie Bazin, Nick Scroxton, Christof Pearce, Anna L.C. Hughes, E. Sutherland, Daniel Garijo, Bronwen Konecky, Richard J. Telford, A. J. Waite, Jennifer E. Hertzberg, Aubrey L. Hillman, Kathryn Allen, Samuel L Jaccard, George E. A. Swann, Lydia A. Olaka, Jianghui Du, Montserrat Alonso-Garcia, Andreas Schmittner, Elizabeth R. Thomas, Will Hobbs, Cécile Pignol, S.E. Pilaar Birch, Natalia Piotrowska, Maria-Serena Poli, Adam Z. Csank, Fabien Arnaud, A.A. Prokopenko, Julien Emile-Geay, Nils Weitzel, Steven J. Phipps, Zoë Thomas, Helen McGregor, Simon Goring, Deborah Khider, Lucien von Gunten, Thomas Felis, Matthew Huber, Lukas Jonkers, Mai Winstrup, Steve George, Yarrow Axford, Elizabeth Bradley, William R Gray, J. C. Bregy, Andrew G. Bunn, Kristine L. DeLong, G. Le Roux, Kaustubh Thirumalai, John W. Williams, Judson W. Partin, Vyacheslav Lyubchich, Georgina Falster, S. A. Truebe, Jiaoyang Ruan, Kim M. Cobb, Suellyn Emerick, Olivier Cartapanis, Fiona D. Hibbert, Yuan Zhou, Christian Stepanek, Oliver Bothe, H.‐W. Chiang, Eric C. Grimm, Belen Martrat, Peter W. Brewer, René Dommain, Bruno Wilhelm, Nicholas P. McKay, Ning Zhao, Emilie Capron, Pierre Francus, Julie N. Richey, Michael Kahle, Kelsey A. Dyez, Sebastien Bertrand, Yolanda Gil, Manuel Chevalier, Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Climate Service Center [Hambourg] (GERICS), Helmholtz-Zentrum Geesthacht (GKSS), National Physical Laboratory [Teddington] (NPL), Université de Lausanne = University of Lausanne (UNIL), Centre Eau Terre Environnement [Québec] (INRS - ETE), Institut National de la Recherche Scientifique [Québec] (INRS), 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), Paléocéanographie (PALEOCEAN), 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), Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Gestion Territoriale de l'Eau et de l'environnement (UMR GESTE), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), 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), School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA, Centre Technique Agroalimentaire (CTCPA), Service de dermatologie et vénéréologie (CHUV Lausanne), Centre Hospitalier Universitaire Vaudois [Lausanne] (CHUV), Geological Institute (ETHZ), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Brown University, Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Department of Earth and Environmental Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), University of New South Wales [Sydney] (UNSW), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), University of Wisconsin-Madison, Martrat, Belen, Martrat, Belen [0000-0001-9904-9178], University of Lausanne, Lausanne, Switzerland, 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), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Centre d'études de chimie métallurgique (CECM), Centre National de la Recherche Scientifique (CNRS), École pratique des hautes études (EPHE), 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, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)
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010506 paleontology ,Atmospheric Science ,Paleoclimate ,010504 meteorology & atmospheric sciences ,Standardization ,Computer science ,Best practice ,[SDE.MCG]Environmental Sciences/Global Changes ,Big data ,Oceanography ,01 natural sciences ,Terminology ,Grassroots ,Paleoceanography ,[SDV.SA.SF]Life Sciences [q-bio]/Agricultural sciences/Silviculture, forestry ,paleoclimate ,ddc:550 ,best practices ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,550 Earth sciences & geology ,ComputingMilieux_MISCELLANEOUS ,FAIR ,0105 earth and related environmental sciences ,Data ,Community engagement ,business.industry ,Paleontology ,[SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics ,15. Life on land ,[SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM] ,Data science ,[SDE.ES]Environmental Sciences/Environmental and Society ,Metadata ,data ,13. Climate action ,paleoceanography ,standards ,Institut für Geowissenschaften ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,business ,Working group - Abstract
The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches. ©2019. American Geophysical Union. All Rights Reserved., Code and data to reproduce the figures of this article are available on GitHub and released on Zenodo (doi:10.5281/zenodo.3165019). Definition of properties and recommendations are summarized here: http://wiki.linked.earth/PaCTS_v1.0 . This work was supported by the National Science Foundation through the EarthCube Program with Grant ICER‐1541029. Feedback solicitation on the standard was facilitated by the Past Global Changes (PAGES) organization. The 2016 workshop on Paleoclimate Data Standards was hosted by the World Data Service for Paleoclimatology (WDS/NOAA‐Paleo), and the participation of international attendees was made possible by a PAGES travel grant. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
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- 2019
16. Northern Borneo stalagmite records reveal West Pacific hydroclimate across MIS 5 and 6
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Kim M. Cobb, Stacy A. Carolin, Judson W. Partin, Syria Lejau, Jean Lynch-Stieglitz, Jenny Malang, Andrew Alek Tuen, B. F. C. Clark, Jess F. Adkins, and J. W. Moerman
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Speleothem ,Stalagmite ,Forcing (mathematics) ,010502 geochemistry & geophysics ,01 natural sciences ,Geophysics ,13. Climate action ,Space and Planetary Science ,Geochemistry and Petrology ,Climatology ,Paleoclimatology ,Interglacial ,Earth and Planetary Sciences (miscellaneous) ,Deglaciation ,Walker circulation ,Glacial period ,Geology ,0105 earth and related environmental sciences - Abstract
Over the past decades, tropical stalagmite δ^(18)O records have provided valuable insight on glacial and interglacial hydrological variability and its relationship to a variety of natural climate forcings. The transition out of the penultimate glaciation (MIS 6) represents an important target for tropical hydroclimate reconstructions, yet relatively few such reconstructions resolve this transition. Particularly, comparisons between Termination 1 and 2 provide critical insight on the extent and influence of proposed climate mechanisms determined from paleorecords and model experiments spanning the recent deglaciation. Here we present a new compilation of western tropical Pacific hydrology spanning 0–160 ky BP, constructed from eleven different U/Th-dated stalagmite δ^(18)O records from Gunung Mulu National Park in northern Borneo. The reconstruction exhibits significant precessional power in phase with boreal fall insolation strength over the 0–160 ky BP period, identifying precessional insolation forcing as the dominant driver of hydroclimate variability in northern Borneo on orbital timescales. A comparison with a network of paleoclimate records from the circum-Pacific suggests the insolation sensitivity may arise from changes in the Walker circulation system. Distinct millennial-scale increases in stalagmite δ^(18)O, indicative of reduced regional convection, occur within glacial terminations and may reflect a response to shifts in inter-hemispheric temperature gradients. Our results imply that hydroclimate in this region is sensitive to external forcing, with a response dominated by large-scale temperature gradients.
- Published
- 2016
17. Transformation of ENSO-related rainwater to dripwater δ 18 O variability by vadose water mixing
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Andrew Alek Tuen, Jenny Malang, B. F. C. Clark, Syria Lejau, Judson W. Partin, Kim M. Cobb, J. W. Moerman, Jess F. Adkins, A. Nele Meckler, and Stacy A. Carolin
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geography ,geography.geographical_feature_category ,δ18O ,Speleothem ,Stalagmite ,Karst ,Isotopes of oxygen ,Rainwater harvesting ,Geophysics ,Climatology ,Vadose zone ,General Earth and Planetary Sciences ,Geology ,Mixing (physics) - Abstract
Speleothem oxygen isotopes (δ18O) are often used to reconstruct past rainfall δ18O variability, and thereby hydroclimate changes, in many regions of the world. However, poor constraints on the karst hydrological processes that transform rainfall signals into cave dripwater add significant uncertainty to interpretations of speleothem-based reconstructions. Here we present several 6.5 year, biweekly dripwater δ18O time series from northern Borneo and compare them to local rainfall δ18O variability. We demonstrate that vadose water mixing is the primary rainfall-to-dripwater transformation process at our site, where dripwater δ18O reflects amount-weighted rainfall δ18O integrated over the previous 3–10 months. We document large interannual dripwater δ18O variability related to the El Nino–Southern Oscillation (ENSO), with amplitudes inversely correlated to dripwater residence times. According to a simple stalagmite forward model, asymmetrical ENSO extremes produce significant offsets in stalagmite δ18O time series given different dripwater residence times. Our study highlights the utility of generating multiyear, paired time series of rainfall and dripwater δ18O to aid interpretations of stalagmite δ18O reconstructions.
- Published
- 2014
18. Comparing proxy and model estimates of hydroclimate variability and change over the Common Era
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Jessica E. Tierney, Thomas Felis, Yochanan Kushnir, Gavin A. Schmidt, Charuta Kulkarni, Justin T. Maxwell, Flavio Lehner, Martin Widmann, Rosanne D'Arrigo, Atsushi Okazaki, Benjamin I. Cook, Sylvia G. Dee, Elena Xoplaki, Bronwen Konecky, Eduardo L. Piovano, Edward R. Cook, Sophie C. Lewis, Deepti Singh, Sloan Coats, Johann H. Jungclaus, Chris Colose, Justin S. Mankin, Wenmin Man, Richard Seager, Samantha Stevenson, Christoph C. Raible, Huan Zhang, Seung H. Baek, Judson W. Partin, Toby R. Ault, Jürg Luterbacher, Caroline Leland, Ailie J. E. Gallant, Jacob Scheff, Alyssa R. Atwood, Davide Zanchettin, Kim M. Cobb, A. Park Williams, Steven J. Phipps, Bette L. Otto-Bliesner, Allegra N. LeGrande, Nathan J. Steiger, Mukund Palat Rao, Kevin J. Anchukaitis, Jonathan G. Palmer, Laia Andreu-Hayles, Alex S. Lopatka, Hans W. Linderholm, Jason E. Smerdon, Michael L. Griffiths, Brendan M. Buckley, and PAGES Hydro2K Consortium
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010504 meteorology & atmospheric sciences ,530 Physics ,Stratigraphy ,lcsh:Environmental protection ,Settore GEO/12 - Oceanografia e Fisica dell'Atmosfera ,Climate change ,010502 geochemistry & geophysics ,01 natural sciences ,Physical Geography and Environmental Geoscience ,Proxy (climate) ,purl.org/becyt/ford/1 [https] ,purl.org/becyt/ford/1.5 [https] ,lcsh:Environmental pollution ,Paleoclimatology ,550 Earth sciences & geology ,Proxy-models ,lcsh:TD169-171.8 ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,lcsh:GE1-350 ,Global and Planetary Change ,Water availability ,Extreme events ,20th century ,Paleontology ,Climate Action ,Fully coupled ,13. Climate action ,Hydroclimate changes ,Climatology ,lcsh:TD172-193.5 ,Environmental science ,Climate model - Abstract
Water availability is fundamental to societies and ecosystems, but our understanding of variations 55 in hydroclimate (includingextreme events, flooding, and decadal periods of drought) is limited because of a paucity of modern instrumental observationsthat are distributed unevenly across the globe and only span parts of the 20th and 21st centuries. Such data coverage isinsufficient for characterizing hydroclimate and its associated dynamics because of its multidecadal-to-centennial variability andhighly regionalized spatial signature. High-resolution (seasonal to decadal) hydroclimatic proxies that span all or parts of the60 Common Era (CE) and paleoclimate model simulations are therefore important tools for augmenting our understanding ofhydroclimate variability. In particular, the comparison of the two sources of information is critical for addressing theuncertainties and limitations of both, while enriching each of their interpretations. We review the principal proxy data availablefor hydroclimatic reconstructions over the CE and highlight contemporary understanding of how these proxies are interpreted ashydroclimate indicators. We also review the available last-millennium simulations from fully-coupled climate models and65 discuss several outstanding challenges associated with simulating hydroclimate variability and change over the CE. A specificreview of simulated hydroclimatic changes forced by volcanic events is provided, as well as a discussion of expectedimprovements in estimated forcings, models and their implementation in the future. Our review of hydroclimatic proxies andlast-millennium model simulations is used as the basis for articulating a variety of considerations and best practices for how toperform proxy-model comparisons of CE hydroclimate. This discussion provides a framework for how best to evaluate70 hydroclimate variability and its associated dynamics using these comparisons, as well as how they can better informinterpretations of both proxy data and model simulations. We subsequently explore means of using proxy-model comparisonsto better constrain and characterize future hydroclimate risks. This is explored specifically in the context of several examplesthat demonstrate how proxy-model comparisons can be used to quantitatively constrain future hydroclimatic risks as estimatedfrom climate model projections. Fil: Smerdon, Jason E.. Columbia University; Estados Unidos Fil: Luterbacher, Jürg. University Of Giessen; Alemania Fil: Phipps, Steven J.. University of Tasmania; Australia Fil: Anchukaitis, Kevin J.. University of Arizona; Estados Unidos Fil: Ault, Toby. Cornell University; Estados Unidos Fil: Coats, Sloan. State University of Colorado at Boulder; Estados Unidos Fil: Cobb, Kim M.. Instituto Tecnológico de Georgia; Estados Unidos Fil: Cook, Benjamin I.. Nasa Goddard Institute For Space Studies; Estados Unidos Fil: Colose, Chris. Nasa Goddard Institute For Space Studies; Estados Unidos Fil: Felis, Thomas. Universitat Bremen; Alemania Fil: Gallant, Ailie. Monash University; Australia Fil: Jungclaus, Johann H.. Max-Planck-Institute for Meteorology; Alemania Fil: Konecky, Bronwen. State University of Colorado at Boulder; Estados Unidos Fil: LeGrande, Allegra. NASA Goddard Institute for Space Studie; Estados Unidos Fil: Lewis, Sophie. The Australian National University; Australia Fil: Lopatka, Alex S.. University of Maryland; Estados Unidos Fil: Man, Wenmin. Chinese Academy of Sciences; República de China Fil: Mankin, Justin S.. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos. NASA Goddard Institute for Space Studies; Estados Unidos Fil: Maxwell, Justin T.. Indiana University; Estados Unidos Fil: Otto-Bliesner, Bette L.. National Center for Atmospheric Research; Estados Unidos Fil: Partin, Judson W.. University of Texas at Austin; Estados Unidos Fil: Singh, Deepti. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Stevenson, Samantha. National Center for Atmospheric Research; Estados Unidos Fil: Tierney, Jessica E.. Arizona State University; Estados Unidos Fil: Zanchettin, Davide. Ca’ Foscari University of Venice; Italia Fil: Zhang, Huan. Justus Liebig University; Alemania Fil: Atwood, Alyssa R.. Georgia Institute of Technology; Estados Unidos. Brown University; Estados Unidos Fil: Andreu Hayles, Laia. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Baek, Seung H.. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Buckley, Brendan. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Cook, Edward. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: D'Arrigo, Rosanne. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Dee, Sylvia G.. Brown University; Estados Unidos Fil: Griffiths, Michael L.. William Paterson University; Estados Unidos Fil: Kulkarni, Charuta. City University of New York; Estados Unidos Fil: Kushnir, Yochanan. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Lehner, Flavio. National Center for Atmospheric Research; Estados Unidos Fil: Leland, Caroline. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Linderholm, Hans W.. University of Gothenburg; Suecia Fil: Okazaki, Atsushi. University of Tokyo; Japón Fil: Palmer, Jonathan. University of New South Wales; Australia Fil: Piovano, Eduardo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina Fil: Raible, Christoph C.. University of Bern; Suiza Fil: Rao, Mukund P.. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Scheff, Jacob. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Schmidt, Gavin A.. NASA Goddard Institute for Space Studie; Estados Unidos Fil: Seager, Richard. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Widmann, Martin. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Park Williams, A.. Lamont-Doherty Earth Observatory of Columbia University; Estados Unidos Fil: Xoplaki, Elena. Justus Liebig University; Alemania
- Published
- 2017
19. Persistent decadal-scale rainfall variability in the tropical South Pacific Convergence Zone through the past six centuries
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Ke Lin, Christopher R. Maupin, Kaustubh Thirumalai, Judson W. Partin, Frederick W. Taylor, Terrence M. Quinn, Jay L. Banner, D. J. Sinclair, and Chuan-Chou Shen
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lcsh:GE1-350 ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,δ18O ,lcsh:Environmental protection ,Stratigraphy ,Paleontology ,Climate change ,Stalagmite ,Oceanography ,lcsh:Environmental pollution ,Cave ,Climatology ,lcsh:TD172-193.5 ,Period (geology) ,lcsh:TD169-171.8 ,Thermohaline circulation ,South Pacific convergence zone ,Scale (map) ,lcsh:Environmental sciences ,Geology - Abstract
Observations and reconstructions of decadal-scale climate variability are necessary to place predictions of future global climate change into temporal context (Goddard et al., 2012). This is especially true for decadal-scale climate variability that originates in the Pacific Ocean (Deser et al., 2004; Dong and Lu, 2013). We focus here on the western tropical Pacific (Solomon Islands; ~ 9.5° S, ~ 160° E), a region directly influenced by: the South Pacific Convergence Zone (SPCZ), the West Pacific Warm Pool (WPWP), the Pacific Walker Circulation (PWC), and the Hadley Circulation. We calibrate δ18O variations in a fast growing stalagmite to local rainfall amount and produce a 600 yr record of rainfall variability from the zonally oriented, tropical portion of the SPCZ. We present evidence for large (~ 1.5 m), persistent and decade(s)-long shifts in total annual rainfall amount in the Solomon Islands since 1416 ± 5 CE. The timing of the decadal changes in rainfall inferred from the 20th century portion of the stalagmite δ18O record coincide with previously identified decadal shifts in Pacific ocean-atmosphere behavior (Clement et al., 2011; Deser et al., 2004). The 600 yr Solomons stalagmite δ18O record indicates that decadal oscillations in rainfall are a robust characteristic of SPCZ-related climate variability, which has important implications to water resource management in this region.
- Published
- 2014
20. A 50-Year Sr/Ca Time Series from an Enclosed, Shallow-Water Guam Coral: In situ Monitoring and Extraction of a Temperature Trend, Annual Cycle, and ENSO and PDO Signals
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Richard H. Randall, Judson W. Partin, Tomoko Bell, Nancy G. Prouty, Mark A. Lander, and John W. Jenson
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010504 meteorology & atmospheric sciences ,Ecology ,010505 oceanography ,Discharge ,Terrigenous sediment ,δ18O ,Annual cycle ,01 natural sciences ,Western Hemisphere Warm Pool ,Oceanography ,Paleoclimatology ,Environmental science ,Seawater ,Pacific decadal oscillation ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Water Science and Technology - Abstract
Bell, T.; Lander, M.A.; Jenson, J.W.; Randall, R.H.; Partin, J.W., and Prouty, N.G., 2019. A 50-year Sr/Ca time series from an enclosed, shallow-water Guam coral: In situ monitoring and extraction of a temperature trend, annual cycle, and ENSO and PDO signals. Journal of Coastal Research, 35(2), 269–286. Coconut Creek (Florida), ISSN 0749-0208.Located on the northern edge of the West Pacific Warm Pool and having a developed economy and modern infrastructure, Guam is well positioned and equipped for obtaining natural records of the west Pacific maritime paleoclimate. This study was a proof of concept to explore whether useful climate proxy records might be obtained from coral at readily accessible, even if geochemically nonoptimal, coastal sites. A 50-year Sr/Ca record (1960–2010) was thus obtained from a shallow-water, near-shore Porites lutea colony at a recreational facility inside Guam's Apra Harbor and compared with local and regional meteorological records, including the El Nino–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) indices. The accessibility of the site enabled documentation of relevant environmental variables for 16 months (September 2009–December 2010): seawater δ18O, pH, seawater cations, and nitrate. Time series of seawater δ18O, pH, and cations show evidence of freshwater input from direct rainfall and stream discharge into the harbor. An anomalously higher mean and variable concentrations of Ba suggest the presence of river-borne, fine-grained terrigenous sediment. Nevertheless, the Sr/Ca time series reproduces a long-term warming trend seen in historical records of local air temperature and regional sea-surface temperature (SST) and closely tracks the ENSO and PDO indices over the entire 50-year record. The consistency of the results with Guam's historical instrumental records, previous coral δ18O results from Guam obtained by others, and previous Sr/Ca proxy results for SST in similar environments elsewhere demonstrate that accessible near-shore sites—where environmental conditions can be monitored—can produce useful Sr/Ca records of local and regional climate phenomena.
- Published
- 2019
21. Multidecadal rainfall variability in South Pacific Convergence Zone as revealed by stalagmite geochemistry
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Ke Lin, Chun Huh, Jay L. Banner, Frederick W. Taylor, Charles S. Jackson, D. J. Sinclair, Christopher R. Maupin, Terrence M. Quinn, Judson W. Partin, Julien Emile-Geay, and Chuan-Chou Shen
- Subjects
Wet season ,geography ,geography.geographical_feature_category ,Intertropical Convergence Zone ,Geology ,Stalagmite ,Structural basin ,Convergence zone ,Isotopes of oxygen ,Oceanography ,Cave ,Climatology ,South Pacific convergence zone - Abstract
Pacifi c decadal variability (PDV) causes widespread, persistent fl uctuations that affect climate, water resources, and fi sheries throughout the Pacifi c basin, yet the magnitude, frequency, and causes of PDV remain poorly constrained. Here we present an absolutely dated, subannually resolved, 446 yr stable oxygen isotope (δ 18 O) cave record of rainfall variability in Vanuatu (southern Pacifi c Ocean), a location that has a climate heavily infl uenced by the South Pacifi c Convergence Zone (SPCZ). The δ 18 O-based proxy rainfall record is dominated by changes in stalagmite δ 18 O that are large (~1‰), quasi-periodic (~50 yr period), and generally abrupt (within 5‐10 yr). These isotopic changes imply abrupt rainfall changes of as much as ~1.8 m per wet season, changes that can be ~2.5◊ larger than the 1976 C.E. shift in rainfall amount associated with a PDV phase switch. The Vanuatu record also shares little commonality with previously documented changes in the Intertropical Convergence Zone during the Little Ice Age or solar forcing. We conclude that multidecadal SPCZ variability is likely of an endogenous nature. Large, spontaneous, and low-frequency changes in SPCZ rainfall during the past 500 yr have important implications for the relative magnitude of natural PDV possible in the coming century.
- Published
- 2013
22. Trace metal and carbon isotopic variations in cave dripwater and stalagmite geochemistry from northern Borneo
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Jess F. Adkins, Andrew Alek Tuen, Judson W. Partin, B. F. C. Clark, and Kim M. Cobb
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Calcite ,geography ,geography.geographical_feature_category ,Geochemistry ,Speleothem ,Stalagmite ,Last Glacial Maximum ,Karst ,chemistry.chemical_compound ,Geophysics ,chemistry ,Cave ,Geochemistry and Petrology ,Paleoclimatology ,Holocene ,Geology - Abstract
We investigate stalagmite trace metal ratios and carbon isotopic composition (δ^(13)C) as potential paleoclimate proxies by comparing cave dripwaters, stalagmites, and bedrock composition from Gunung Mulu and Gunung Buda National Parks in northern Borneo, a tropical rainforest karst site. Three year long, biweekly time series of dripwater Mg/Ca, Sr/Ca, and δ^(13)C from several drips at our site are not correlated with rainfall variability, indicative of a relatively weak relationship between hydroclimate and dripwater geochemistry at our site. However, combining all of the dripwater geochemical data gathered over four field trips to our site (N > 300 samples), we find that drips with highly variable Mg[Sr]/Ca have relatively invariable δ^(18)O values close to the mean. We hypothesize that increased residence times translate into reduced variance in dripwater δ^(18)O through mixing in the epikarst as well as increased Mg[Sr]/Ca values through increased calcite precipitation in the epikarst. Mg/Ca, Sr/Ca, and δ^(13)C time series from three overlapping stalagmites that grew over the last 27 kyrs are characterized by strong centennial-scale variations, and bear little resemblance to previously published, well-reproduced δ^(18)O time series from the same stalagmites. The only shared signal among the three stalagmites' geochemical time series is a relative decrease of 1‰ in δ^(13)C from the Last Glacial Maximum to the Holocene, consistent with a transition from savannah (C4) to rainforest (C3) conditions documented in nearby records. Taken together, our study indicates that stalagmite Mg[Sr]/Ca ratios are poor indicators of hydroclimate conditions at our site, while stalagmite δ^(13)C exhibits some reproducible signals on glacial-interglacial timescales.
- Published
- 2013
23. Statistical constraints on El Niño Southern Oscillation reconstructions using individual foraminifera: A sensitivity analysis
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Kaustubh Thirumalai, Judson W. Partin, Charles S. Jackson, and Terrence M. Quinn
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biology ,δ18O ,Paleontology ,Multivariate ENSO index ,Oceanography ,biology.organism_classification ,Standard deviation ,Foraminifera ,Amplitude ,Climatology ,Range (statistics) ,Uncertainty quantification ,Thermocline ,Geology - Abstract
Recent investigations of submillennial paleoceanographic variability have attempted to resolve high-frequency climate signals such as the El Nino Southern Oscillation (ENSO) using the population statistics of individual planktic foraminiferal δ18O analyses. This approach is complicated by the relatively short lifespan of individual foraminifers (~2–4 weeks) compared to the time represented by a typical marine sediment sample (~decades to millennia). Here, we investigate the uncertainty associated with individual foraminiferal analyses (IFA) through simulations on forward modeled δ18Ocarbonate. First, focusing on the Nino3.4 region of the tropical Pacific Ocean, a bootstrap Monte Carlo algorithm is developed to constrain the uncertainty on IFA-statistics. Subsequently, to test the sensitivity of IFA to changes in seasonal cycle amplitude, ENSO amplitude, and ENSO frequency, synthetic time series of δ18Ocarbonate with differing variability are constructed and tested with our algorithm. The probabilities of the IFA technique in detecting changes in ENSO amplitude and seasonal cycle amplitude (or a combination of both) for the surface ocean and thermocline at different locations in the tropical Pacific are quantified. We find that the uncertainty in the standard deviation is smaller than the range, that the IFA-signal is insensitive to ENSO frequency, and at certain locations the seasonal cycle may dominate ENSO. IFA sensitivity towards ENSO is highest at the central equatorial Pacific surface ocean and the eastern equatorial Pacific (EEP) thermocline whereas sensitivity towards the seasonal cycle is highest at the EEP surface ocean. Our results suggest that rigorous uncertainty quantification should become standard practice for accurately interpreting IFA-data.
- Published
- 2013
24. Magnesium and strontium systematics in tropical speleothems from the Western Pacific
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John M. U. Jocson, Blaž Miklavič, John E. Mylroie, Ethan Goddard, Judson W. Partin, Terrence M. Quinn, Frederick W. Taylor, John W. Jenson, Daniel J. Sinclair, and Jay L. Banner
- Subjects
Calcite ,geography ,Strontium ,geography.geographical_feature_category ,Geochemistry ,Speleothem ,Mineralogy ,chemistry.chemical_element ,Geology ,Stalagmite ,Diagenesis ,chemistry.chemical_compound ,chemistry ,Geochemistry and Petrology ,Precipitation ,Quaternary ,Holocene - Abstract
We present bulk average Sr and Mg data for 13 speleothems from different locations in the western equatorial Pacific (Guam, Solomon Islands, and Vanuatu). These data plot on a single straight line in a graph of ln(Sr/Ca) vs ln(Mg/Ca) with a slope of ~ 0.9. A 22,000 year record of Sr and Mg in one of these samples from Guam also plots with the same slope, suggesting that the process partitioning Mg and Sr within the Guam speleothem is the same as the one that partitions Mg and Sr between the different Pacific speleothems. We rule out temperature, growth rate, detrital phases, and sea-spray as likely mechanisms for this correlation. We construct mathematical models of limestone diagenesis and show that this cannot explain the slope of the correlation. Our favoured explanation for the correlation is calcite/water interaction in the form of prior calcite precipitation (PCP) and/or incongruent calcite dissolution (ICD). We present a formal mathematical model of PCP and prove that the slope of a graph of ln(Sr/Ca) and ln(Mg/Ca) is given by Kd Sr − 1 Kd Mg − 1 . A similar equation is derived for ICD in a companion paper ( Sinclair, 2011 ). Using published values for KdSr and KdMg, this slope is calculated to be ~ 0.88, in excellent agreement with our observations. Because the slope is independent of solution and host-limestone composition it can be used to diagnose calcite–water interaction in individual cave water studies where host rock composition is unknown, or in speleothems for which no field drip water data or host-rock geochemistry exists. Approximately half of published drip and speleothem Mg + Sr studies plot within error of this slope. We hypothesize that the overall trend in our Pacific speleothem data results from the individual dripwater systems evolving from a roughly similar initial rock composition set by late Quaternary reef limestone. In the Guam speleothem, the broad peak in Mg and Sr centred on the early–mid Holocene reflects a change in hydrology (rainfall), with the most likely scenario being that dry conditions prevailed on Guam at this time.
- Published
- 2012
25. Potential risks to freshwater resources as a result of leakage from CO2 geological storage: a batch-reaction experiment
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Corinne I. Wong, Judson W. Partin, Jiemin Lu, and Susan D. Hovorka
- Subjects
Hydrology ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,Chemistry ,Dolomite ,Carbonate minerals ,Soil Science ,Geology ,Aquifer ,Pollution ,Monitoring program ,chemistry.chemical_compound ,Environmental chemistry ,Groundwater pollution ,Carbon dioxide ,Environmental Chemistry ,Water pollution ,Groundwater ,Earth-Surface Processes ,Water Science and Technology - Abstract
In assessing the feasibility of widespread deployment of CO2 geological storage, it is prudent to first assess potential consequences of an error or accident that could lead to CO2 leakage into groundwater resources above a sequestration interval. Information about the sensitivity of the groundwater system to introduction of CO2 is needed in order to design groundwater monitoring program. A laboratory-batch experiment was conducted to explore the range of CO2 impact on groundwater quality of a spectrum of representative aquifers, in the Gulf Coast region, USA. Results show that CO2 elevated concentrations of many cations within hours or days. Two types of cations were recognized according to their concentration trends. Type I cations—Ca, Mg, Si, K, Sr, Mn, Ba, Co, B, Zn—rapidly increased following initial CO2 flux and reached stable concentrations before the end of the experiment. Type II cations—Fe, Al, Mo, U, V, As, Cr, Cs, Rb, Ni and Cu—increased at the start of CO2 flux, but declined, in most cases, to levels lower than pre-CO2 concentrations. Dissolution of dolomite and calcite caused the largest increase in concentrations for Ca, Mg, Mn, Ba and Sr. Cation release rates decreased linearly as pH increased during mineral buffering. Experiment results suggest that carbonate minerals are the dominant contributor of changes in groundwater quality. Risk assessments of potential degradation of groundwater and monitoring strategies should focus on these fast-reacting minerals. Mobilization risk of Type II cations, however, may be self-mitigated because adsorption occurs when pH rebounds.
- Published
- 2009
26. Millennial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum
- Author
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Kim M. Cobb, Diego P. Fernandez, Jess F. Adkins, B. F. C. Clark, and Judson W. Partin
- Subjects
Hydrology ,Multidisciplinary ,Oceanography ,Global warming ,Paleoclimatology ,Abrupt climate change ,Climate change ,Younger Dryas ,Radiative forcing ,Western Hemisphere Warm Pool ,Geology ,Pacific decadal oscillation - Abstract
Models and palaeoclimate data suggest that the tropical Pacific climate system plays a key part in the mechanisms underlying orbital-scale and abrupt climate change. Atmospheric convection over the western tropical Pacific is a major source of heat and moisture to extratropical regions, and may therefore influence the global climate response to a variety of forcing factors. The response of tropical Pacific convection to changes in global climate boundary conditions, abrupt climate changes and radiative forcing remains uncertain, however. Here we present three absolutely dated oxygen isotope records from stalagmites in northern Borneo that reflect changes in west Pacific warm pool hydrology over the past 27,000 years. Our results suggest that convection over the western tropical Pacific weakened 18,000-20,000 years ago, as tropical Pacific and Antarctic temperatures began to rise during the early stages of deglaciation. Convective activity, as inferred from oxygen isotopes, reached a minimum during Heinrich event 1 (ref. 10), when the Atlantic meridional overturning circulation was weak, pointing to feedbacks between the strength of the overturning circulation and tropical Pacific hydrology. There is no evidence of the Younger Dryas event in the stalagmite records, however, suggesting that different mechanisms operated during these two abrupt deglacial climate events. During the Holocene epoch, convective activity appears to track changes in spring and autumn insolation, highlighting the sensitivity of tropical Pacific convection to external radiative forcing. Together, these findings demonstrate that the tropical Pacific hydrological cycle is sensitive to high-latitude climate processes in both hemispheres, as well as to external radiative forcing, and that it may have a central role in abrupt climate change events.
- Published
- 2007
27. Gradual onset and recovery of the Younger Dryas abrupt climate event in the tropics
- Author
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Yuko M. Okumura, Judson W. Partin, Frederick W. Taylor, Hsun-Ming Hu, Fernando P. Siringan, Jay L. Banner, Terrence M. Quinn, Chuan-Chou Shen, Kai-Yin Lin, and M. B. Cardenas
- Subjects
geography ,Multidisciplinary ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Meteorology ,Gradual onset ,General Physics and Astronomy ,Tropics ,General Chemistry ,010502 geochemistry & geophysics ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Proxy (climate) ,Article ,13. Climate action ,Climatology ,Sea ice ,Deglaciation ,Abrupt climate change ,Climate model ,14. Life underwater ,Younger Dryas ,Geology ,0105 earth and related environmental sciences - Abstract
Proxy records of temperature from the Atlantic clearly show that the Younger Dryas was an abrupt climate change event during the last deglaciation, but records of hydroclimate are underutilized in defining the event. Here we combine a new hydroclimate record from Palawan, Philippines, in the tropical Pacific, with previously published records to highlight a difference between hydroclimate and temperature responses to the Younger Dryas. Although the onset and termination are synchronous across the records, tropical hydroclimate changes are more gradual (>100 years) than the abrupt (10–100 years) temperature changes in the northern Atlantic Ocean. The abrupt recovery of Greenland temperatures likely reflects changes in regional sea ice extent. Proxy data and transient climate model simulations support the hypothesis that freshwater forced a reduction in the Atlantic meridional overturning circulation, thereby causing the Younger Dryas. However, changes in ocean overturning may not produce the same effects globally as in Greenland., The Younger Dryas cooling event has been identified in ice records in the Northern Hemisphere, but the effects of this cold snap on the tropics are poorly known. Here, the authors present a speleothem record and model simulations, showing that tropical hydroclimate recovered slower than temperatures in Greenland.
- Published
- 2014
28. Probing the Cl–HCl complex via bond-specific photodissociation of (HCl)2
- Author
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Curt Wittig, K. Liu, I. Bezel, A. Kolessov, and Judson W. Partin
- Subjects
Dimer ,Photodissociation ,General Physics and Astronomy ,Resonance (chemistry) ,Photochemistry ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Excited state ,Translational energy ,Rydberg formula ,symbols ,Physical and Theoretical Chemistry ,Spectroscopy - Abstract
Infrared–ultraviolet double resonance has been used to photodissociate the free HCl bond of the HCl dimer. This creates Cl–HCl in a coherent superposition of electronic and vibrational states. Measurement of the translational energy of the departing H atom using high- n Rydberg time-of-flight spectroscopy enables the Cl–HCl potential surfaces to be probed. The features thus obtained agree with theoretical estimates. At long IR–UV delays, the fastest H atoms derive primarily from UV photodissociation of internally excited HCl (e.g., high rotational levels) formed by (HCl) 2 predissociation.
- Published
- 1999
29. Testing the annual nature of speleothem banding
- Author
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Ke Lin, Wuhui Duan, Xiuyang Jiang, Hai Cheng, R. Lawrence Edwards, Chuan-Chou Shen, Ming Tan, and Judson W. Partin
- Subjects
geography ,Paleontology ,Multidisciplinary ,geography.geographical_feature_category ,Cave ,High resolution ,Speleothem ,Stalagmite ,Biology ,Article ,Chronology - Abstract
Speleothem laminae have been postulated to form annually and this lamina-chronology is widely applied to high-resolution modern and past climate reconstructions. However, this argument has not been directly supported by high resolution dating methods. Here we present contemporary single-lamina 230Th dating techniques with 2σ precision as good as ±0.5 yr on a laminated stalagmite with density couplets from Xianren Cave, China, that covers the last 300 years. We find that the layers do not always deposit annually. Annual bands can be under- or over-counted by several years during different multi-decadal intervals. The irregular formation of missing and false bands in this example indicates that the assumption of annual speleothem laminae in a climate reconstruction should be approached carefully without a robust absolute-dated chronology.
- Published
- 2013
30. A coral-based reconstruction of sea surface salinity at Sabine Bank, Vanuatu from 1842 to 2007 CE
- Author
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Bernard Pelletier, Meaghan K. Gorman, Guy Cabioch, James A. Austin, Christophe Maes, Judson W. Partin, Frederick W. Taylor, S. Saustrup, Valérie Ballu, and Terrence M. Quinn
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Advection ,δ18O ,Coral ,Paleontology ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Salinity ,SSS ,13. Climate action ,Climatology ,14. Life underwater ,Sea surface salinity ,Surface water ,Geology ,Channel (geography) ,0105 earth and related environmental sciences - Abstract
Climate variability associated with the El Nino Southern Oscillation (ENSO) results in large sea-surface temperature (SST) and sea-surface salinity (SSS) anomalies in many regions of the tropical Pacific Ocean. We investigate interannual changes in SSS driven by ENSO in the southwestern Pacific at Sabine Bank, Vanuatu (SBV, 166.04°E, 15.94°S) using monthly variations in coralδ18O from 1842 to 2007 CE. We develop and apply a coral δ18O-SSS transfer function, which is assessed using a calibration-verification exercise (1970-2007 CE). The 165-year reconstructed SSS record contains a prominent trend toward freshening from 1842 to 2007 CE; mean SSS for 1842-1872 CE is 35.46 ± 0.28 psu, which contrasts with a mean value of 34.85 ± 0.31 psu for 1977-2007 CE, with a freshening trend during the latter part of the 20th century that is not unprecedented with respect to the overall record. Variance in the record is concentrated in the interannual (42%) and interdecadal (29%) bands. The SBV-SSS record matches well with a similarly reconstructed SSS time series at Malo Channel, Vanuatu, which is located ∼120 km to the east of SBV. This regional signal is likely driven by ENSO-related changes in the SPCZ and interdecadal changes in surface water advection. The pattern of interdecadal variability at SBV agrees reasonably well with coral records of interdecadal variability from Fiji and Tonga, especially in the pre-1940 portions of the records, further evidence for the regional extent of the salinity signal at Sabine Bank, Vanuatu.
- Published
- 2012
31. Relationship between modern rainfall variability, cave dripwater, and stalagmite geochemistry in Guam, USA
- Author
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John W. Jenson, B. F. Hardt, Jay L. Banner, Danko Taboroši, John M. U. Jocson, Frederick W. Taylor, Blaž Miklavič, Mark A. Lander, D. J. Sinclair, Tomoko Bell, Judson W. Partin, and Terrence M. Quinn
- Subjects
Wet season ,Hydrology ,geography ,geography.geographical_feature_category ,δ18O ,Geochemistry ,Speleothem ,Stalagmite ,Western Hemisphere Warm Pool ,Geophysics ,Cave ,Geochemistry and Petrology ,Paleoclimatology ,Precipitation ,Geology - Abstract
[1] Modern rainwater, cave dripwater and cave stalagmite geochemical time series from a cave in Guam (13°38′N, 144°53′E) are used to better understand how changes in cave stalagmite geochemistry relate to aboveground changes in rainfall at a tropical location. A scientific field team based in Guam collects ∼monthly samples from multiple sites for geochemical analyses at a cave and aboveground rainfall from a nearby location. We compute a transfer function between rainfall amount and oxygen isotopic composition (δ18O) of a decrease (increase) of 0.94 ± 0.3 m/year for every 1‰ increase (decrease) in rainfall δ18O, based on data extracted from the International Atomic Energy Agency (IAEA) Global Networks of Isotopes in Precipitation (GNIP) database and from data generated in this study. Dripwater δ18O and Mg/Ca ratios show annual cyclicity at some, but not all sites, accentuating the complex nature of cave hydrology. A stalagmite δ18O record for the last ∼160 years indicates the existence of droughts of decadal length, when rainfall is estimated to be ∼0.65 ± 0.3 m/year less than average conditions. This estimate of rainfall reduction most likely refers to wet season months, as these months preferentially contribute to groundwater recharge. The proxy-based climate record at Guam provides new evidence highlighting how a rainy site in the Western Pacific Warm Pool today can experience considerable changes in rainfall on decadal timescales.
- Published
- 2012
32. Climate variability recorded in tropical and sub-tropical speleothems
- Author
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Kim M. Cobb, Jay L. Banner, and Judson W. Partin
- Subjects
business.industry ,Climatology ,Environmental resource management ,Sustainability ,Environmental science ,Subtropics ,business ,Commons ,Inclusion (education) - Abstract
This Article is brought to you for free and open access by the Environmental Sustainability at Scholar Commons. It has been accepted for inclusion inEnvironmental Sustainability Publications by an authorized administrator of Scholar Commons. For more information, please contactscholarcommons@usf.edu.
- Published
- 2008
33. Erratum: Millennial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum
- Author
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Jess F. Adkins, Kim M. Cobb, Judson W. Partin, B. F. C. Clark, and Diego P. Fernandez
- Subjects
Multidisciplinary ,Oceanography ,Hydrology (agriculture) ,Scale (ratio) ,Last Glacial Maximum ,Western Hemisphere Warm Pool ,Geology - Published
- 2009
34. A Century of Reduced ENSO Variability During the Medieval Climate Anomaly
- Author
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Terrence M. Quinn, Frederick W. Taylor, Tsai-Luen Yu, Judson W. Partin, Chuan-Chou Shen, Meaghan K. Gorman, Chung-Che Wu, Kaustubh Thirumalai, and A. E. Lawman
- Subjects
bepress|Physical Sciences and Mathematics ,EarthArXiv|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Anomaly (natural sciences) ,Climate system ,EarthArXiv|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology|Climate ,Paleontology ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,EarthArXiv|Physical Sciences and Mathematics ,Sea surface temperature ,bepress|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology|Climate ,El Niño Southern Oscillation ,13. Climate action ,Climatology ,bepress|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology ,Environmental science ,Climate model ,14. Life underwater ,Probabilistic framework ,0105 earth and related environmental sciences - Abstract
Climate model simulations of El Niño–Southern Oscillation (ENSO) behavior for the last millennium demonstrate interdecadal to centennial changes in ENSO variability that can arise purely from stochastic processes internal to the climate system. That said, the instrumental record of ENSO does not have the temporal coverage needed to capture the full range of natural ENSO variability observed in long, unforced climate model simulations. Here we demonstrate a probabilistic framework to quantify changes in ENSO variability via histograms and probability density functions using monthly instrumental and coral‐based sea surface temperature (SST) anomalies from 1900–2005 and 1051–1150 CE. We find that reconstructed SST anomalies from modern corals from the southwest Pacific capture changes in ENSO variability that are consistent with instrumental SST data from the central equatorial Pacific. Fossil coral records indicate 100 years of relatively lower ENSO variability during part of the Medieval Climate Anomaly. Our results demonstrate that periods of reduced ENSO variability can last a century, far longer in duration than modern observations in the instrumental record of ENSO, but consistent with results from unforced climate model simulations
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