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1. X-ray induced photoconductivity and its correlation with structural and chemical defects in heteroepitaxial diamond.

Author

Grünwald, T., Bestele, C., Bosak, M., Zhao, J., Newton, M. E., and Schreck, M.

Subjects
*PHOTOCONDUCTIVITY, *DIAMOND crystals, *X-rays, *DISLOCATION density, *DIAMONDS
Abstract

Three sets of heteroepitaxial diamond crystals grown under nominally identical process conditions on Ir/YSZ/Si(001) substrates have been studied with respect to structural defects, chemical purity, and x-ray induced photoconductivity (PC). The dislocation density that varied systematically between 10 7 and 10 9 cm − 2 had a minor influence on dark conductivity and photoconductive gain G. In contrast, the substitutional nitrogen (N N ) and substitutional boron (N B ) defects, which are both present at very low concentrations (≤ 1 ppb), turned out to be the crucial factors controlling the electrical behavior. Small differences between both resulted in variations of the photocurrents by up to 5 orders of magnitude. The maximum in G of 0.75 × 10 4 was measured in the sample with highest dark conductivity. It could be explained conclusively within our model calculations on gain formation by N N ≤ N B . For low gain samples, we found N N > --> N B . However, the measured G values were far from theoretical predictions. This indicates a dominating role of additional traps. After x-ray switch-off, persistent photoconductivity (PPC) was observed in high gain samples. It was attributed to an energetic barrier hampering the recharging of nitrogen atoms by hole capture. As a possible source, strain fields generated by dislocations are suggested. [ABSTRACT FROM AUTHOR]

Published
2023
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4. Reading tea leaves worldwide: Decoupled drivers of initial litter decomposition mass‐loss rate and stabilization

Author

Sarneel, J., Hefting, M., Sandén, T., van den Hoogen, J., Routh, D., Adhikari, B., Alatalo, J., Aleksanyan, A., Althuizen, I., Alsafran, M., Atkins, J., Augusto, L., Aurela, M., Azarov, A., Barrio, I., Beier, C., Bejarano, M., Benham, S., Berg, B., Bezler, N., Björnsdóttir, K., Bolinder, M., Carbognani, M., Cazzolla Gatti, R., Chelli, S., Chistotin, M., Christiansen, C., Courtois, P., Crowther, T., Dechoum, M., Djukic, I., Duddigan, S., Egerton‐Warburton, L., Fanin, N., Fantappiè, M., Fares, S., Fernandes, G., Filippova, N., Fliessbach, A., Fuentes, D., Godoy, R., Grünwald, T., Guzmán, G., Hawes, J., He, Y., Hero, J.‐M., Hess, L., Hogendoorn, K., Høye, T., Jans, W., Jónsdóttir, I., Keller, S., Kepfer‐Rojas, S., Kuz'menko, N., Larsen, K., Laudon, H., Lembrechts, J., Li, J., Limousin, J.‐M., Lukin, S., Marques, R., Marín, C., McDaniel, M., Meek, Q., Merzlaya, G., Michelsen, A., Montagnani, L., Mueller, P., Murugan, R., Myers‐Smith, I., Nolte, S., Ochoa‐Hueso, R., Okafor, B., Okorkov, V., Onipchenko, V., Orozco, M., Parkhurst, T., Peres, C., Petit Bon, M., Petraglia, A., Pingel, M., Rebmann, C., Scheffers, B., Schmidt, I., Scholes, M., Sheffer, E., Shevtsova, L., Smith, S., Sofo, A., Stevenson, P., Strouhalová, B., Sundsdal, A., Sühs, R., Tamene, G., Thomas, H., Tolunay, D., Tomaselli, M., Tresch, S., Tucker, D., Ulyshen, M., Valdecantos, A., Vandvik, V., Vanguelova, E., Verheyen, K., Wang, X., Yahdjian, L., Yumashev, X., Keuskamp, J., Sarneel, J., Hefting, M., Sandén, T., van den Hoogen, J., Routh, D., Adhikari, B., Alatalo, J., Aleksanyan, A., Althuizen, I., Alsafran, M., Atkins, J., Augusto, L., Aurela, M., Azarov, A., Barrio, I., Beier, C., Bejarano, M., Benham, S., Berg, B., Bezler, N., Björnsdóttir, K., Bolinder, M., Carbognani, M., Cazzolla Gatti, R., Chelli, S., Chistotin, M., Christiansen, C., Courtois, P., Crowther, T., Dechoum, M., Djukic, I., Duddigan, S., Egerton‐Warburton, L., Fanin, N., Fantappiè, M., Fares, S., Fernandes, G., Filippova, N., Fliessbach, A., Fuentes, D., Godoy, R., Grünwald, T., Guzmán, G., Hawes, J., He, Y., Hero, J.‐M., Hess, L., Hogendoorn, K., Høye, T., Jans, W., Jónsdóttir, I., Keller, S., Kepfer‐Rojas, S., Kuz'menko, N., Larsen, K., Laudon, H., Lembrechts, J., Li, J., Limousin, J.‐M., Lukin, S., Marques, R., Marín, C., McDaniel, M., Meek, Q., Merzlaya, G., Michelsen, A., Montagnani, L., Mueller, P., Murugan, R., Myers‐Smith, I., Nolte, S., Ochoa‐Hueso, R., Okafor, B., Okorkov, V., Onipchenko, V., Orozco, M., Parkhurst, T., Peres, C., Petit Bon, M., Petraglia, A., Pingel, M., Rebmann, C., Scheffers, B., Schmidt, I., Scholes, M., Sheffer, E., Shevtsova, L., Smith, S., Sofo, A., Stevenson, P., Strouhalová, B., Sundsdal, A., Sühs, R., Tamene, G., Thomas, H., Tolunay, D., Tomaselli, M., Tresch, S., Tucker, D., Ulyshen, M., Valdecantos, A., Vandvik, V., Vanguelova, E., Verheyen, K., Wang, X., Yahdjian, L., Yumashev, X., and Keuskamp, J.

Abstract

The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.

Published
2024
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5. ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales

Author

Qiu, C, Zhu, D, Ciais, P, Guenet, B, Krinner, G, Peng, S, Aurela, M, Bernhofer, C, Brümmer, C, Bret-Harte, S, Chu, H, Chen, J, Desai, AR, Dušek, J, Euskirchen, ES, Fortuniak, K, Flanagan, LB, Friborg, T, Grygoruk, M, Gogo, S, Grünwald, T, Hansen, BU, Holl, D, Humphreys, E, Hurkuck, M, Kiely, G, Klatt, J, Kutzbach, L, Largeron, C, Laggoun-Défarge, F, Lund, M, Lafleur, PM, Li, X, Mammarella, I, Merbold, L, Nilsson, MB, Olejnik, J, Ottosson-Löfvenius, M, Oechel, W, Parmentier, FJW, Peichl, M, Pirk, N, Peltola, O, Pawlak, W, Rasse, D, Rinne, J, Shaver, G, Peter Schmid, H, Sottocornola, M, Steinbrecher, R, Sachs, T, Urbaniak, M, Zona, D, and Ziemblinska, K

Subjects
Earth Sciences
Abstract

Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5° grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (Vcmax) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r2 Combining double low line 0.76; Nash-Sutcliffe modeling efficiency, MEF Combining double low line 0.76) and ecosystem respiration (ER, r2 Combining double low line 0.78, MEF Combining double low line 0.75), with lesser accuracy for latent heat fluxes (LE, r2 Combining double low line 0.42, MEF Combining double low line 0.14) and and net ecosystem CO2 exchange (NEE, r2 Combining double low line 0.38, MEF Combining double low line 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r2 values (0.57-0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r2 values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r2

Published
2018

8. Dataset for 'Joint optimization of land carbon uptake and albedo can help achieve moderate instantaneous and long-term cooling effects'

Author

Graf, A., Musavi, T., Wohlfahrt, G., Aranda-Barranco, S., Arriga, N., Brümmer, C., Ceschia, E., Desai, A.R., Di Lonardo, S., Gharun, M., Grünwald, T., Hörtnagl, L., Kasak, K., Klosterhalfen, A., Knohl, A., Kowalska, N., Lindroth, A., Mauder, M., Migliavacca, M., Rebmann, Corinna, Schmidt, M., Šigut, L., Tomelleri, E., Varlagin, A., Graf, A., Musavi, T., Wohlfahrt, G., Aranda-Barranco, S., Arriga, N., Brümmer, C., Ceschia, E., Desai, A.R., Di Lonardo, S., Gharun, M., Grünwald, T., Hörtnagl, L., Kasak, K., Klosterhalfen, A., Knohl, A., Kowalska, N., Lindroth, A., Mauder, M., Migliavacca, M., Rebmann, Corinna, Schmidt, M., Šigut, L., Tomelleri, E., and Varlagin, A.

Abstract

Both carbon dioxide uptake and albedo of the land surface affect global climate. However, climate change mitigation by increasing carbon uptake can cause a warming trade-off by decreasing albedo, with most research focusing on afforestation and its interaction with snow. Here, we present carbon uptake and albedo observations from 176 globally distributed flux stations. We demonstrate a gradual decline in maximum achievable annual albedo as carbon uptake increases, even within subgroups of non-forest and snow-free ecosystems. Based on a paired-site permutation approach, we quantify the likely impact of land use on carbon uptake and albedo. Shifting to the maximum attainable carbon uptake at each site would likely cause moderate net global warming for the first approximately 20 years, followed by a strong cooling effect. A balanced policy co-optimizing carbon uptake and albedo is possible that avoids warming on any timescale, but results in a weaker long-term cooling effect.

Published
2023

9. Detection and attribution of an anomaly in terrestrial photosynthesis in Europe during the COVID-19 lockdown

Author

Tang, A.C.I., Flechard, C.R., Arriga, N., Papale, D., Stoy, P.C., Buchmann, N., Cuntz, M., Douros, J., Fares, S., Knohl, A., Šigut, L., Simioni, G., Timmermans, R., Grünwald, T., Ibrom, A., Loubet, B., Mammarella, I., Marchesini, L.B., Nilsson, M., Peichl, M., Rebmann, Corinna, Schmidt, M., Bernhofer, C., Berveiller, D., Cremonese, E., El-Madany, T.S., Gharun, M., Gianelle, D., Hörtnagl, L., Roland, M., Varlagin, A., Fu, Z., Heinesch, B., Janssens, I., Kowalska, N., Dušek, J., Gerosa, G., Mölder, M., Tuittila, E.-S., Loustau, D., Tang, A.C.I., Flechard, C.R., Arriga, N., Papale, D., Stoy, P.C., Buchmann, N., Cuntz, M., Douros, J., Fares, S., Knohl, A., Šigut, L., Simioni, G., Timmermans, R., Grünwald, T., Ibrom, A., Loubet, B., Mammarella, I., Marchesini, L.B., Nilsson, M., Peichl, M., Rebmann, Corinna, Schmidt, M., Bernhofer, C., Berveiller, D., Cremonese, E., El-Madany, T.S., Gharun, M., Gianelle, D., Hörtnagl, L., Roland, M., Varlagin, A., Fu, Z., Heinesch, B., Janssens, I., Kowalska, N., Dušek, J., Gerosa, G., Mölder, M., Tuittila, E.-S., and Loustau, D.

Abstract

Carbon dioxide (CO2) uptake by plant photosynthesis, referred to as gross primary production (GPP) at the ecosystem level, is sensitive to environmental factors, including pollutant exposure, pollutant uptake, and changes in the scattering of solar shortwave irradiance (SWin) − the energy source for photosynthesis. The 2020 spring lockdown due to COVID-19 resulted in improved air quality and atmospheric transparency, providing a unique opportunity to assess the impact of air pollutants on terrestrial ecosystem functioning. However, detecting these effects can be challenging as GPP is influenced by other meteorological drivers and management practices. Based on data collected from 44 European ecosystem-scale CO2 flux monitoring stations, we observed significant changes in spring GPP at 34 sites during 2020 compared to 2015–2019. Among these, 14 sites showed an increase in GPP associated with higher SWin, 10 sites had lower GPP linked to atmospheric and soil dryness, and seven sites were subjected to management practices. The remaining three sites exhibited varying dynamics, with one experiencing colder and rainier weather resulting in lower GPP, and two showing higher GPP associated with earlier spring melts. Analysis using the regional atmospheric chemical transport model (LOTOS-EUROS) indicated that the ozone (O3) concentration remained relatively unchanged at the research sites, making it unlikely that O3 exposure was the dominant factor driving the primary production anomaly. In contrast, SWin increased by 9.4 % at 36 sites, suggesting enhanced GPP possibly due to reduced aerosol optical depth and cloudiness. Our findings indicate that air pollution and cloudiness may weaken the terrestrial carbon sink by up to 16 %. Accurate and continuous ground-based observations are crucial for detecting and attributing subtle changes in terrestrial ecosystem functioning in response to environmental and anthropogenic drivers.

Published
2023

10. Joint optimization of land carbon uptake and albedo can help achieve moderate instantaneous and long-term cooling effects

Author

Graf, A., Wohlfahrt, G., Aranda-Barranco, S., Arriga, N., Brümmer, C., Ceschia, E., Ciais, P., Desai, A.R., Di Lonardo, S., Gharun, M., Grünwald, T., Hörtnagl, L., Kasak, K., Klosterhalfen, A., Knohl, A., Kowalska, N., Leuchner, M., Lindroth, A., Mauder, M., Migliavacca, M., Morel, A.C., Pfennig, A., Poorter, H., Poppe Terán, C., Reitz, O., Rebmann, Corinna, Sanchez-Azofeifa, A., Schmidt, M., Šigut, L., Tomelleri, E., Yu, K., Varlagin, A., Vereecken, H., Graf, A., Wohlfahrt, G., Aranda-Barranco, S., Arriga, N., Brümmer, C., Ceschia, E., Ciais, P., Desai, A.R., Di Lonardo, S., Gharun, M., Grünwald, T., Hörtnagl, L., Kasak, K., Klosterhalfen, A., Knohl, A., Kowalska, N., Leuchner, M., Lindroth, A., Mauder, M., Migliavacca, M., Morel, A.C., Pfennig, A., Poorter, H., Poppe Terán, C., Reitz, O., Rebmann, Corinna, Sanchez-Azofeifa, A., Schmidt, M., Šigut, L., Tomelleri, E., Yu, K., Varlagin, A., and Vereecken, H.

Abstract

Both carbon dioxide uptake and albedo of the land surface affect global climate. However, climate change mitigation by increasing carbon uptake can cause a warming trade-off by decreasing albedo, with most research focusing on afforestation and its interaction with snow. Here, we present carbon uptake and albedo observations from 176 globally distributed flux stations. We demonstrate a gradual decline in maximum achievable annual albedo as carbon uptake increases, even within subgroups of non-forest and snow-free ecosystems. Based on a paired-site permutation approach, we quantify the likely impact of land use on carbon uptake and albedo. Shifting to the maximum attainable carbon uptake at each site would likely cause moderate net global warming for the first approximately 20 years, followed by a strong cooling effect. A balanced policy co-optimizing carbon uptake and albedo is possible that avoids warming on any timescale, but results in a weaker long-term cooling effect.

Published
2023

11. CO2 balance of boreal, temperate, and tropical forests derived from a global database

Author

LUYSSAERT, S, INGLIMA, I, JUNG, M, RICHARDSON, AD, REICHSTEIN, M, PAPALE, D, PIAO, SL, SCHULZE, E‐D, WINGATE, L, MATTEUCCI, G, ARAGAO, L, AUBINET, M, BEER, C, BERNHOFER, C, BLACK, KG, BONAL, D, BONNEFOND, J‐M, CHAMBERS, J, CIAIS, P, COOK, B, DAVIS, KJ, DOLMAN, AJ, GIELEN, B, GOULDEN, M, GRACE, J, GRANIER, A, GRELLE, A, GRIFFIS, T, GRÜNWALD, T, GUIDOLOTTI, G, HANSON, PJ, HARDING, R, HOLLINGER, DY, HUTYRA, LR, KOLARI, P, KRUIJT, B, KUTSCH, W, LAGERGREN, F, LAURILA, T, LAW, BE, LE MAIRE, G, LINDROTH, A, LOUSTAU, D, MALHI, Y, MATEUS, J, MIGLIAVACCA, M, MISSON, L, MONTAGNANI, L, MONCRIEFF, J, MOORS, E, MUNGER, JW, NIKINMAA, E, OLLINGER, SV, PITA, G, REBMANN, C, ROUPSARD, O, SAIGUSA, N, SANZ, MJ, SEUFERT, G, SIERRA, C, SMITH, M‐L, TANG, J, VALENTINI, R, VESALA, T, and JANSSENS, IA

Subjects
Climate Action, carbon cycle, CO2, forest ecosystems, global database, gross primary productivity, net ecosystem productivity, net primary productivity, Environmental Sciences, Biological Sciences, Ecology
Abstract

Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome-specific carbon budgets; to re-examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 °C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome-specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non-CO2 carbon fluxes are not presently being adequately accounted for. © 2007 Blackwell Publishing Ltd.

Published
2007

12. Carbon Balance Gradient in European Forests: Should We Doubt 'Surprising' Results? A Reply to Piovesan & Adams

Author

Jarvis, P. G., Dolman, A. J., Matteucci, G., Kowalski, A. S., Ceulemans, R., Rebmann, C., Moors, E. J., Granier, A., Gross, P., Jensen, N. O., Pilegaard, K., Lindroth, A., Grelle, A., Grünwald, T., Aubinet, M., Vesala, T., Rannik, Ü., Berbigier, P., Loustau, D., Guðmundson, J., Ibrom, A., Morgenstern, K., Clement, R., Moncrieff, J., Montagnani, L., Minerbi, S., and Valentini, R.

Published
2001

13. Simulating carbon and water fluxes over croplands with ORCHIDEE-STICS model : Multi-site evaluation and sensitivity to management drivers

Author

Li, L., Vuichard, N., Viovy, N., Ciais, P., Béziat, P., Cellier, P., Ceschia, E., Eugster, W., Grünwald, T., Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Centre d'études spatiales de la biosphère (CESBIO), 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)-Observatoire Midi-Pyrénées (OMP), and 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 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 de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; Cropland ecosystem is one of the most uncertain components of the terrestrial Carbon budget at European scale. In this context, a dual effort has been initiated within the CarboEurope-IP project named as the Cropland Synthesis Activity that aims 1) to monitor and analyse C flux over crop sites and 2) to develop and refine crop model's simulations from site to continental scale. Here, we will present the results obtained with the ORCHIDEE-STICS model within the frame of this activity. In this coupled model, the agronomy-oriented model STICS provides its calculated Leaf Area Index (LAI) to the dynamic global vegetation model ORCHIDEE in order to better calculate the Growth Primary Production (GPP) and related C fluxes for crop ecosystem. With this model we performed simulations on several wheat and maize sites. Overall, ORCHIDEE-STICS agrees well with the observations especially for wheat. We will assess from the misfit between model and data, where structural improvements of the model are needed, and what is the beneficial effect of these improvements. Four main forms of model improvements will be tested : i) optimal adjustment of generic physiological parameters of ORCHIDEE, ii) adjustment of agricultural technology, iii) adjustment of crop varieties phenological parameters and iv) realistic reproduction of each site cultivation history. All this information being rather uncertain at the European scale, this assessment is particularly of importance and will help to rank priorities for future model's developments. The model data comparison will focus on NEE, GPP, Reco fluxes, but also involve latent and sensible heat flux observation.

Published
2023

15. Charge carrier trapping by dislocations in single crystal diamond.

Author

Schreck, M., Ščajev, P., Träger, M., Mayr, M., Grünwald, T., Fischer, M., and Gsell, S.

Subjects
DISLOCATIONS in crystals, DIAMOND crystals, CHARGE carriers, SINGLE crystals, HOT carriers, NANODIAMONDS, OPTICAL pumping
Abstract

Charge carrier trapping in diamond crystals containing well-defined concentrations of dislocations was investigated by several complementary techniques. Samples with dislocation densities ndis between <1 × 107 and ≈1 × 109 cm−2 were grown heteroepitaxially on Ir/YSZ/Si(001). In optical pump–probe experiments, ambipolar diffusion coefficients were determined from the decay of light-induced transient free carrier gratings. Modeling their variation with excitation density yielded trapping cross sections σ of 29 and 10 nm for the dislocations and a stress-field-induced reduction in exciton binding energies from 80 to 73 and 60 meV at ndis = 1 × 108 and 1 × 109 cm−2, respectively. The lifetime measured by induced absorption scaled proportional to 1/ndis with absolute values ranging from 0.1 to 10 ns. In the electrical measurements on two sets of detector slices, electron–hole pairs were excited by α-particles and transport was measured separately for electrons and holes. Both types of carriers showed fast transient current signals. The time constant of the additional slow component exclusively seen for holes was in agreement with the activation energy of boron acceptors. Their concentration of ≈0.5 ppb yielded σ = 1.77 × 10−13 cm2 for charged point traps. Schubweg and carrier lifetime due to deep trapping roughly reproduced the 1/ndis trend. For electrons at 3 V/μm, a value σ = 40 nm was deduced. Cross sections for holes were significantly smaller. Differences in hole trapping between the samples are attributed to charging of dislocations controlled by chemical impurities. Increase in lifetime at high voltages is explained by reduced capture cross sections for hot carriers. [ABSTRACT FROM AUTHOR]

Published
2020
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16. Spruce Forests (Norway and Sitka Spruce, Including Douglas Fir): Carbon and Water Fluxes and Balances, Ecological and Ecophysiological Determinants

Author

Bernhofer, C., Aubinet, M., Clement, R., Grelle, A., Grünwald, T., Ibrom, A., Jarvis, P., Rebmann, C., Schulze, E.-D., Tenhunen, J. D., Baldwin, I. T., editor, Caldwell, M. M., editor, Heldmaier, G., editor, Lange, O. L., editor, Mooney, H. A., editor, Schulze, E.-D., editor, Sommer, U., editor, and Valentini, Riccardo, editor

Published
2003
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17. Standardization of Eddy Covariance Measurements: role of setup, calculation and filtering

Author

Papale, D., Shaukat, S., Sabbatini, S., Nicolini, G., Moffat, A.M., Belelli Marchesini, L., Heinesch, B., Berveiller, D., Brummer, C., Brut, A., Chipeaux, C., Czerný, R., Graf, A., Grünwald, T., Hörtnagl, L.K., Klosterhalfen, A., Lafont, S., Manise, T., Montagnani, L., Moreaux, V., Peichl, M., Schrader, F., and Tallec, T.

Subjects
Settore BIO/07 - ECOLOGIA
Published
2022

18. Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived from Flux-Tower Measurements

Author

Gilmanov, Tagir G., Aires, L., Barcza, Z., Baron, V. S., Belelli, L., Beringer, J., Billesbach, D., Bonal, D., Bradford, J., Ceschia, E., Cook, D., Corradi, C., Frank, A., Gianelle, D., Gimeno, C., Gruenwald, T., Guo, Haiqiang, Hanan, N., Haszpra, L., Heilman, J., Jacobs, A., Jones, M. B., Johnson, D. A., Kiely, G., Li, Shenggong, Magliulo, V., Moors, E., Nagy, Z., Nasyrov, M., Owensby, C., Pinter, K., Pio, C., Reichstein, M., Sanz, M. J., Scott, R., Soussana, J. F., Stoy, P. C., Svejcar, T., Tuba, Z., and Zhou, Guangsheng

Published
2010
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20. Management effects on net ecosystem carbon and GHG budgets at European crop sites

Author

Ceschia, E., Béziat, P., Dejoux, J.F., Aubinet, M., Bernhofer, Ch., Bodson, B., Buchmann, N., Carrara, A., Cellier, P., Di Tommasi, P., Elbers, J.A., Eugster, W., Grünwald, T., Jacobs, C.M.J., Jans, W.W.P., Jones, M., Kutsch, W., Lanigan, G., Magliulo, E., Marloie, O., Moors, E.J., Moureaux, C., Olioso, A., Osborne, B., Sanz, M.J., Saunders, M., Smith, P., Soegaard, H., and Wattenbach, M.

Published
2010
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22. The net biome production of full crop rotations in Europe

Author

Kutsch, W.L., Aubinet, M., Buchmann, N., Smith, P., Osborne, B., Eugster, W., Wattenbach, M., Schrumpf, M., Schulze, E.D., Tomelleri, E., Ceschia, E., Bernhofer, C., Béziat, P., Carrara, A., Di Tommasi, P., Grünwald, T., Jones, M., Magliulo, V., Marloie, O., Moureaux, C., Olioso, A., Sanz, M.J., Saunders, M., Søgaard, H., and Ziegler, W.

Published
2010
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24. Method comparison of indirect assessments of understory leaf area index (LAIu): A case study across the extended network of ICOS forest ecosystem sites in Europe

Author

George, J.-P., Yang, W., Kobayashi, H., Biermann, T., Carrara, A., Cremonese, E., Cuntz, M., Fares, S., Gerosa, G., Grünwald, T., Hase, Jan Niklas, Heliasz, M., Ibrom, A., Knohl, A., Kruijt, B., Lange, H., Limousin, J.-M., Loustau, D., Lukeš, P., Marzuoli, R., Mölder, M., Montagnani, L., Neirynck, J., Peichl, M., Rebmann, Corinna, Schmidt, M., Lopez Serrano, F.R., Soudani, K., Vincke, C., Pisek, J., George, J.-P., Yang, W., Kobayashi, H., Biermann, T., Carrara, A., Cremonese, E., Cuntz, M., Fares, S., Gerosa, G., Grünwald, T., Hase, Jan Niklas, Heliasz, M., Ibrom, A., Knohl, A., Kruijt, B., Lange, H., Limousin, J.-M., Loustau, D., Lukeš, P., Marzuoli, R., Mölder, M., Montagnani, L., Neirynck, J., Peichl, M., Rebmann, Corinna, Schmidt, M., Lopez Serrano, F.R., Soudani, K., Vincke, C., and Pisek, J.

Abstract

Leaf area index (LAI) is a key ecological indicator for describing the structure of canopies and for modelling energy exchange between atmosphere and biosphere. While LAI of the forest overstory can be accurately assessed over large spatial scales via remote sensing, LAI of the forest understory (LAIu) is still largely ignored in ecological studies and ecosystem modelling due to the fact that it is often too complex to be destructively sampled or approximated by other site parameters. Additionally, so far only few attempts have been made to retrieve understory LAI via remote sensing, because dense canopies with high LAI are often hindering retrieval algorithms to produce meaningful estimates for understory LAI. Consequently, the forest understory still constitutes a poorly investigated research realm impeding ecological studies to properly account for its contribution to the energy absorption capacity of forest stands. This study aims to compare three conceptually different indirect retrieval methodologies for LAIu over a diverse panel of forest understory types distributed across Europe. For this we carried out near-to-surface measurements of understory reflectance spectra as well as digital surface photography over the extended network of Integrated Carbon Observation System (ICOS) forest ecosystem sites. LAIu was assessed by exploiting the empirical relationship between vegetation cover and light absorption (Beer-Lambert- Bouguer law) as well as by utilizing proposed relationships with two prominent vegetation indices: normalized difference vegetation index (NDVI) and simple ratio (SR). Retrievals from the three methods were significantly correlated with each other (r = 0.63–0.99, RMSE = 0.53–0.72), but exhibited also significant bias depending on the LAI scale. The NDVI based retrieval approach most likely overestimates LAI at productive sites when LAIu > 2, while the simple ratio algorithm overestimat

Published
2021

25. Retrieval and validation of forest background reflectivity from daily Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) data across European forests

Author

Pisek, J., Erb, A., Korhonen, L., Biermann, T., Carrara, A., Cremonese, E., Cuntz, M., Fares, S., Gerosa, G., Grünwald, T., Hase, Jan Niklas, Heliasz, M., Ibrom, A., Knohl, A., Kobler, J., Kruijt, B., Lange, H., Leppänen, L., Limousin, J.-M., Lopez Serrano, F.R., Loustau, D., Lukeš, P., Lundin, L., Marzuoli, R., Mölder, M., Montagnani, L., Neirynck, J., Peichl, M., Rebmann, Corinna, Rubio, E., Santos-Reis, M., Schaaf, C., Schmidt, M., Simioni, G., Soudani, K., Vincke, C., Pisek, J., Erb, A., Korhonen, L., Biermann, T., Carrara, A., Cremonese, E., Cuntz, M., Fares, S., Gerosa, G., Grünwald, T., Hase, Jan Niklas, Heliasz, M., Ibrom, A., Knohl, A., Kobler, J., Kruijt, B., Lange, H., Leppänen, L., Limousin, J.-M., Lopez Serrano, F.R., Loustau, D., Lukeš, P., Lundin, L., Marzuoli, R., Mölder, M., Montagnani, L., Neirynck, J., Peichl, M., Rebmann, Corinna, Rubio, E., Santos-Reis, M., Schaaf, C., Schmidt, M., Simioni, G., Soudani, K., and Vincke, C.

Abstract

Information about forest background reflectance is needed for accurate biophysical parameter retrieval from forest canopies (overstory) with remote sensing. Separating under- and overstory signals would enable more accurate modeling of forest carbon and energy fluxes. We retrieved values of the normalized difference vegetation index (NDVI) of the forest understory with the multi-angular Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo data (gridded 500 m daily Collection 6 product), using a method originally developed for boreal forests. The forest floor background reflectance estimates from the MODIS data were compared with in situ understory reflectance measurements carried out at an extensive set of forest ecosystem experimental sites across Europe. The reflectance estimates from MODIS data were, hence, tested across diverse forest conditions and phenological phases during the growing season to examine their applicability for ecosystems other than boreal forests. Here we report that the method can deliver good retrievals, especially over different forest types with open canopies (low foliage cover). The performance of the method was found to be limited over forests with closed canopies (high foliage cover), where the signal from understory becomes too attenuated. The spatial heterogeneity of individual field sites and the limitations and documented quality of the MODIS BRDF product are shown to be important for the correct assessment and validation of the retrievals obtained with remote sensing.

Published
2021

26. Author Correction: The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

Author

Pastorello, G, Trotta, C, Canfora, E, Chu, H, Christianson, D, Cheah, Y-W, Poindexter, C, Chen, J, Elbashandy, A, Humphrey, M, Isaac, P, Polidori, D, Reichstein, M, Ribeca, A, van Ingen, C, Vuichard, N, Zhang, L, Amiro, B, Ammann, C, Arain, MA, Ardö, J, Arkebauer, T, Arndt, SK, Arriga, N, Aubinet, M, Aurela, M, Baldocchi, D, Barr, A, Beamesderfer, E, Marchesini, LB, Bergeron, O, Beringer, J, Bernhofer, C, Berveiller, D, Billesbach, D, Black, TA, Blanken, PD, Bohrer, G, Boike, J, Bolstad, PV, Bonal, D, Bonnefond, J-M, Bowling, DR, Bracho, R, Brodeur, J, Brümmer, C, Buchmann, N, Burban, B, Burns, SP, Buysse, P, Cale, P, Cavagna, M, Cellier, P, Chen, S, Chini, I, Christensen, TR, Cleverly, J, Collalti, A, Consalvo, C, Cook, BD, Cook, D, Coursolle, C, Cremonese, E, Curtis, PS, D’Andrea, E, da Rocha, H, Dai, X, Davis, KJ, De Cinti, B, de Grandcourt, A, De Ligne, A, De Oliveira, RC, Delpierre, N, Desai, AR, Di Bella, CM, di Tommasi, P, Dolman, H, Domingo, F, Dong, G, Dore, S, Duce, P, Dufrêne, E, Dunn, A, Dušek, J, Eamus, D, Eichelmann, U, ElKhidir, HAM, Eugster, W, Ewenz, CM, Ewers, B, Famulari, D, Fares, S, Feigenwinter, I, Feitz, A, Fensholt, R, Filippa, G, Fischer, M, Frank, J, Galvagno, M, Gharun, M, Gianelle, D, Gielen, B, Gioli, B, Gitelson, A, Goded, I, Goeckede, M, Goldstein, AH, Gough, CM, Goulden, ML, Graf, A, Griebel, A, Gruening, C, Grünwald, T, Hammerle, A, Han, S, Han, X, Hansen, BU, Hanson, C, Hatakka, J, He, Y, Hehn, M, Heinesch, B, Hinko-Najera, N, Hörtnagl, L, Hutley, L, Ibrom, A, Ikawa, H, Jackowicz-Korczynski, M, Janouš, D, Jans, W, Jassal, R, Jiang, S, Kato, T, Khomik, M, Klatt, J, Knohl, A, Knox, S, Kobayashi, H, Koerber, G, Kolle, O, Kosugi, Y, Kotani, A, Kowalski, A, Kruijt, B, Kurbatova, J, Kutsch, WL, Kwon, H, Launiainen, S, Laurila, T, Law, B, Leuning, R, Li, Y, Liddell, M, Limousin, J-M, Lion, M, Liska, AJ, Lohila, A, López-Ballesteros, A, López-Blanco, E, Loubet, B, Loustau, D, Lucas-Moffat, A, Lüers, J, Ma, S, Macfarlane, C, Magliulo, V, Maier, R, Mammarella, I, Manca, G, Marcolla, B, Margolis, HA, Marras, S, Massman, W, Mastepanov, M, Matamala, R, Matthes, JH, Mazzenga, F, McCaughey, H, McHugh, I, McMillan, AMS, Merbold, L, Meyer, W, Meyers, T, Miller, SD, Minerbi, S, Moderow, U, Monson, RK, Montagnani, L, Moore, CE, Moors, E, Moreaux, V, Moureaux, C, Munger, JW, Nakai, T, Neirynck, J, Nesic, Z, Nicolini, G, Noormets, A, Northwood, M, Nosetto, M, Nouvellon, Y, Novick, K, Oechel, W, Olesen, JE, Ourcival, J-M, Papuga, SA, Parmentier, F-J, Paul-Limoges, E, Pavelka, M, Peichl, M, Pendall, E, Phillips, RP, Pilegaard, K, Pirk, N, Posse, G, Powell, T, Prasse, H, Prober, SM, Rambal, S, Rannik, Ü, Raz-Yaseef, N, Rebmann, C, Reed, D, de Dios, VR, Restrepo-Coupe, N, Reverter, BR, Roland, M, Sabbatini, S, Sachs, T, Saleska, SR, Sánchez-Cañete, EP, Sanchez-Mejia, ZM, Schmid, HP, Schmidt, M, Schneider, K, Schrader, F, Schroder, I, Scott, RL, Sedlák, P, Serrano-Ortíz, P, Shao, C, Shi, P, Shironya, I, Siebicke, L, Šigut, L, Silberstein, R, Sirca, C, Spano, D, Steinbrecher, R, Stevens, RM, Sturtevant, C, Suyker, A, Tagesson, T, Takanashi, S, Tang, Y, Tapper, N, Thom, J, Tomassucci, M, Tuovinen, J-P, Urbanski, S, Valentini, R, van der Molen, M, van Gorsel, E, van Huissteden, K, Varlagin, A, Verfaillie, J, Vesala, T, Vincke, C, Vitale, D, Vygodskaya, N, Walker, JP, Walter-Shea, E, Wang, H, Weber, R, Westermann, S, Wille, C, Wofsy, S, Wohlfahrt, G, Wolf, S, Woodgate, W, Zampedri, R, Zhang, J, Zhou, G, Zona, D, Agarwal, D, Biraud, S, Torn, M, Papale, D, Pastorello, G, Trotta, C, Canfora, E, Chu, H, Christianson, D, Cheah, Y-W, Poindexter, C, Chen, J, Elbashandy, A, Humphrey, M, Isaac, P, Polidori, D, Reichstein, M, Ribeca, A, van Ingen, C, Vuichard, N, Zhang, L, Amiro, B, Ammann, C, Arain, MA, Ardö, J, Arkebauer, T, Arndt, SK, Arriga, N, Aubinet, M, Aurela, M, Baldocchi, D, Barr, A, Beamesderfer, E, Marchesini, LB, Bergeron, O, Beringer, J, Bernhofer, C, Berveiller, D, Billesbach, D, Black, TA, Blanken, PD, Bohrer, G, Boike, J, Bolstad, PV, Bonal, D, Bonnefond, J-M, Bowling, DR, Bracho, R, Brodeur, J, Brümmer, C, Buchmann, N, Burban, B, Burns, SP, Buysse, P, Cale, P, Cavagna, M, Cellier, P, Chen, S, Chini, I, Christensen, TR, Cleverly, J, Collalti, A, Consalvo, C, Cook, BD, Cook, D, Coursolle, C, Cremonese, E, Curtis, PS, D’Andrea, E, da Rocha, H, Dai, X, Davis, KJ, De Cinti, B, de Grandcourt, A, De Ligne, A, De Oliveira, RC, Delpierre, N, Desai, AR, Di Bella, CM, di Tommasi, P, Dolman, H, Domingo, F, Dong, G, Dore, S, Duce, P, Dufrêne, E, Dunn, A, Dušek, J, Eamus, D, Eichelmann, U, ElKhidir, HAM, Eugster, W, Ewenz, CM, Ewers, B, Famulari, D, Fares, S, Feigenwinter, I, Feitz, A, Fensholt, R, Filippa, G, Fischer, M, Frank, J, Galvagno, M, Gharun, M, Gianelle, D, Gielen, B, Gioli, B, Gitelson, A, Goded, I, Goeckede, M, Goldstein, AH, Gough, CM, Goulden, ML, Graf, A, Griebel, A, Gruening, C, Grünwald, T, Hammerle, A, Han, S, Han, X, Hansen, BU, Hanson, C, Hatakka, J, He, Y, Hehn, M, Heinesch, B, Hinko-Najera, N, Hörtnagl, L, Hutley, L, Ibrom, A, Ikawa, H, Jackowicz-Korczynski, M, Janouš, D, Jans, W, Jassal, R, Jiang, S, Kato, T, Khomik, M, Klatt, J, Knohl, A, Knox, S, Kobayashi, H, Koerber, G, Kolle, O, Kosugi, Y, Kotani, A, Kowalski, A, Kruijt, B, Kurbatova, J, Kutsch, WL, Kwon, H, Launiainen, S, Laurila, T, Law, B, Leuning, R, Li, Y, Liddell, M, Limousin, J-M, Lion, M, Liska, AJ, Lohila, A, López-Ballesteros, A, López-Blanco, E, Loubet, B, Loustau, D, Lucas-Moffat, A, Lüers, J, Ma, S, Macfarlane, C, Magliulo, V, Maier, R, Mammarella, I, Manca, G, Marcolla, B, Margolis, HA, Marras, S, Massman, W, Mastepanov, M, Matamala, R, Matthes, JH, Mazzenga, F, McCaughey, H, McHugh, I, McMillan, AMS, Merbold, L, Meyer, W, Meyers, T, Miller, SD, Minerbi, S, Moderow, U, Monson, RK, Montagnani, L, Moore, CE, Moors, E, Moreaux, V, Moureaux, C, Munger, JW, Nakai, T, Neirynck, J, Nesic, Z, Nicolini, G, Noormets, A, Northwood, M, Nosetto, M, Nouvellon, Y, Novick, K, Oechel, W, Olesen, JE, Ourcival, J-M, Papuga, SA, Parmentier, F-J, Paul-Limoges, E, Pavelka, M, Peichl, M, Pendall, E, Phillips, RP, Pilegaard, K, Pirk, N, Posse, G, Powell, T, Prasse, H, Prober, SM, Rambal, S, Rannik, Ü, Raz-Yaseef, N, Rebmann, C, Reed, D, de Dios, VR, Restrepo-Coupe, N, Reverter, BR, Roland, M, Sabbatini, S, Sachs, T, Saleska, SR, Sánchez-Cañete, EP, Sanchez-Mejia, ZM, Schmid, HP, Schmidt, M, Schneider, K, Schrader, F, Schroder, I, Scott, RL, Sedlák, P, Serrano-Ortíz, P, Shao, C, Shi, P, Shironya, I, Siebicke, L, Šigut, L, Silberstein, R, Sirca, C, Spano, D, Steinbrecher, R, Stevens, RM, Sturtevant, C, Suyker, A, Tagesson, T, Takanashi, S, Tang, Y, Tapper, N, Thom, J, Tomassucci, M, Tuovinen, J-P, Urbanski, S, Valentini, R, van der Molen, M, van Gorsel, E, van Huissteden, K, Varlagin, A, Verfaillie, J, Vesala, T, Vincke, C, Vitale, D, Vygodskaya, N, Walker, JP, Walter-Shea, E, Wang, H, Weber, R, Westermann, S, Wille, C, Wofsy, S, Wohlfahrt, G, Wolf, S, Woodgate, W, Zampedri, R, Zhang, J, Zhou, G, Zona, D, Agarwal, D, Biraud, S, Torn, M, and Papale, D

Abstract

The following authors were omitted from the original version of this Data Descriptor: Markus Reichstein and Nicolas Vuichard. Both contributed to the code development and N. Vuichard contributed to the processing of the ERA-Interim data downscaling. Furthermore, the contribution of the co-author Frank Tiedemann was re-evaluated relative to the colleague Corinna Rebmann, both working at the same sites, and based on this re-evaluation a substitution in the co-author list is implemented (with Rebmann replacing Tiedemann). Finally, two affiliations were listed incorrectly and are corrected here (entries 190 and 193). The author list and affiliations have been amended to address these omissions in both the HTML and PDF versions.

Published
2021

27. Improving the representation of cropland sites in the Community Land Model (CLM) version 5.0

Author

Boas, T, Bogena, H, Grünwald, T, Heinesch, B, Ryu, D, Schmidt, M, Vereecken, H, Western, A, Hendricks-Franssen, H-J, Boas, T, Bogena, H, Grünwald, T, Heinesch, B, Ryu, D, Schmidt, M, Vereecken, H, Western, A, and Hendricks-Franssen, H-J

Abstract

The incorporation of a comprehensive crop module in land surface models offers the possibility to study the effect of agricultural land use and land management changes on the terrestrial water, energy and biogeochemical cycles. It may help to improve the simulation of biogeophysical and biogeochemical processes on regional and global scales in the framework of climate and land use change. In this study, the performance of the crop module of the Community Land Model version 5 (CLM5) was evaluated at point scale with site specific field data focussing on the simulation of seasonal and inter-annual variations in crop growth, planting and harvesting cycles, and crop yields as well as water, energy and carbon fluxes. In order to better represent agricultural sites, the model was modified by (1) implementing the winter wheat subroutines after Lu et al. (2017) in CLM5; (2) implementing plant specific parameters for sugar beet, potatoes and winter wheat, thereby adding these crop functional types (CFT) to the list of actively managed crops in CLM5; (3) introducing a cover cropping subroutine that allows multiple crop types on the same column within one year. The latter modification allows the simulation of cropping during winter months before usual cash crop planting begins in spring, which is a common agricultural management technique in humid and sub-humid regions. We compared simulation results with field data and found that both the parameterization of the CFTs, as well as the winter wheat subroutines, led to a significant simulation improvement in terms of energy fluxes, leaf area index (LAI), net ecosystem exchange (RMSE reduction for latent and sensible heat by up to 57 % and 59 % respectively) and crop yield (up to 87 % improvement in winter wheat yield prediction) compared with default model results. The cover cropping subroutine yielded a substantial improvement in representation of field conditions after harvest of the main cash crop (winter season) in terms of L

Published
2020

28. Altered energy partitioning across terrestrial ecosystems in the European drought year 2018

Author

Graf, A., Klosterhalfen, A., Arriga, N., Bernhofer, C., Bogena, H., Bornet, F., Brüggemann, N., Brümmer, C., Buchmann, N., Chi, J., Chipeaux, C., Cremonese, E., Cuntz, M., Dušek, J., El-Madany, T.S., Fares, S., Fischer, M., Foltýnová, L., Gharun, M., Ghiasi, S., Gielen, B., Gottschalk, P., Grünwald, T., Heinemann, G., Heinesch, B., Heliasz, M., Holst, J., Hörtnagl, L., Ibrom, A., Ingwersen, J., Jurasinski, G., Klatt, J., Knohl, A., Koebsch, F., Konopka, J., Korkiakoski, M., Kowalska, N., Kremer, P., Kruijt, B., Lafont, S., Léonard, J., de Ligne, A., Longdoz, B., Loustau, D., Magliulo, V., Mammarella, I., Manca, G., Mauder, M., Migliavacca, M., Mölder, M., Neirynck, J., Ney, P., Nilsson, M., Paul-Limoges, E., Peichl, M., Pitacco, A., Poyda, A., Rebmann, Corinna, Roland, M., Sachs, T., Schmidt, M., Schrader, F., Siebicke, L., Šigut, L., Tuittila, E.-S., Varlagin, A., Vendrame, N., Vincke, C., Völksch, I., Weber, S., Wille, C., Wizemann, H.-D., Zeeman, M., Vereecken, H., Graf, A., Klosterhalfen, A., Arriga, N., Bernhofer, C., Bogena, H., Bornet, F., Brüggemann, N., Brümmer, C., Buchmann, N., Chi, J., Chipeaux, C., Cremonese, E., Cuntz, M., Dušek, J., El-Madany, T.S., Fares, S., Fischer, M., Foltýnová, L., Gharun, M., Ghiasi, S., Gielen, B., Gottschalk, P., Grünwald, T., Heinemann, G., Heinesch, B., Heliasz, M., Holst, J., Hörtnagl, L., Ibrom, A., Ingwersen, J., Jurasinski, G., Klatt, J., Knohl, A., Koebsch, F., Konopka, J., Korkiakoski, M., Kowalska, N., Kremer, P., Kruijt, B., Lafont, S., Léonard, J., de Ligne, A., Longdoz, B., Loustau, D., Magliulo, V., Mammarella, I., Manca, G., Mauder, M., Migliavacca, M., Mölder, M., Neirynck, J., Ney, P., Nilsson, M., Paul-Limoges, E., Peichl, M., Pitacco, A., Poyda, A., Rebmann, Corinna, Roland, M., Sachs, T., Schmidt, M., Schrader, F., Siebicke, L., Šigut, L., Tuittila, E.-S., Varlagin, A., Vendrame, N., Vincke, C., Völksch, I., Weber, S., Wille, C., Wizemann, H.-D., Zeeman, M., and Vereecken, H.

Abstract

Drought and heat events, such as the 2018 European drought, interact with the exchange of energy between the land surface and the atmosphere, potentially affecting albedo, sensible and latent heat fluxes, as well as CO2 exchange. Each of these quantities may aggravate or mitigate the drought, heat, their side effects on productivity, water scarcity and global warming. We used measurements of 56 eddy covariance sites across Europe to examine the response of fluxes to extreme drought prevailing most of the year 2018 and how the response differed across various ecosystem types (forests, grasslands, croplands and peatlands). Each component of the surface radiation and energy balance observed in 2018 was compared to available data per site during a reference period 2004–2017. Based on anomalies in precipitation and reference evapotranspiration, we classified 46 sites as drought affected. These received on average 9% more solar radiation and released 32% more sensible heat to the atmosphere compared to the mean of the reference period. In general, drought decreased net CO2 uptake by 17.8%, but did not significantly change net evapotranspiration. The response of these fluxes differed characteristically between ecosystems; in particular, the general increase in the evaporative index was strongest in peatlands and weakest in croplands.

Published
2020

29. The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data.

Author

Pastorello G, Trotta C, Canfora E, Chu H, Christianson D, Cheah Y-W, Poindexter C, Chen J, Elbashandy A, Humphrey M, Isaac P, Polidori D, Ribeca A, van Ingen C, Zhang L, Amiro B, Ammann C, Arain MA, Ardö J, Arkebauer T, Arndt SK, Arriga N, Aubinet M, Aurela M, Baldocchi D, Barr A, Beamesderfer E, Marchesini LB, Bergeron O, Beringer J, Bernhofer C, Berveiller D, Billesbach D, Black TA, Blanken PD, Bohrer G, Boike J, Bolstad PV, Bonal D, Bonnefond J-M, Bowling DR, Bracho R, Brodeur J, Brümmer C, Buchmann N, Burban B, Burns SP, Buysse P, Cale P, Cavagna M, Cellier P, Chen S, Chini I, Christensen TR, Cleverly J, Collalti A, Consalvo C, Cook BD, Cook D, Coursolle C, Cremonese E, Curtis PS, D'Andrea E, da Rocha H, Dai X, Davis KJ, De Cinti B, de Grandcourt A, De Ligne A, De Oliveira RC, Delpierre N, Desai AR, Di Bella CM, di Tommasi P, Dolman H, Domingo F, Dong G, Dore S, Duce P, Dufrêne E, Dunn A, Dušek J, Eamus D, Eichelmann U, ElKhidir HAM, Eugster W, Ewenz CM, Ewers B, Famulari D, Fares S, Feigenwinter I, Feitz A, Fensholt R, Filippa G, Fischer M, Frank J, Galvagno M, Gharun M, Gianelle D, Gielen B, Gioli B, Gitelson A, Goded I, Goeckede M, Goldstein AH, Gough CM, Goulden ML, Graf A, Griebel A, Gruening C, Grünwald T, Hammerle A, Han S, Han X, Hansen BU, Hanson C, Hatakka J, He Y, Hehn M, Heinesch B, Hinko-Najera N, Hörtnagl L, Hutley L, Ibrom A, Ikawa H, Jackowicz-Korczynski M, Janouš D, Jans W, Jassal R, Jiang S, Kato T, Khomik M, Klatt J, Knohl A, Knox S, Kobayashi H, Koerber G, Kolle O, Kosugi Y, Kotani A, Kowalski A, Kruijt B, Kurbatova J, Kutsch WL, Kwon H, Launiainen S, Laurila T, Law B, Leuning R, Li Y, Liddell M, Limousin J-M, Lion M, Liska AJ, Lohila A, López-Ballesteros A, López-Blanco E, Loubet B, Loustau D, Lucas-Moffat A, Lüers J, Ma S, Macfarlane C, Magliulo V, Maier R, Mammarella I, Manca G, Marcolla B, Margolis HA, Marras S, Massman W, Mastepanov M, Matamala R, Matthes JH, Mazzenga F, McCaughey H, McHugh I, McMillan AMS, Merbold L, Meyer W, Meyers T, Miller SD, Minerbi S, Moderow U, Monson RK, Montagnani L, Moore CE, Moors E, Moreaux V, Moureaux C, Munger JW, Nakai T, Neirynck J, Nesic Z, Nicolini G, Noormets A, Northwood M, Nosetto M, Nouvellon Y, Novick K, Oechel W, Olesen JE, Ourcival J-M, Papuga SA, Parmentier F-J, Paul-Limoges E, Pavelka M, Peichl M, Pendall E, Phillips RP, Pilegaard K, Pirk N, Posse G, Powell T, Prasse H, Prober SM, Rambal S, Rannik Ü, Raz-Yaseef N, Reed D, de Dios VR, Restrepo-Coupe N, Reverter BR, Roland M, Sabbatini S, Sachs T, Saleska SR, Sánchez-Cañete EP, Sanchez-Mejia ZM, Schmid HP, Schmidt M, Schneider K, Schrader F, Schroder I, Scott RL, Sedlák P, Serrano-Ortíz P, Shao C, Shi P, Shironya I, Siebicke L, Šigut L, Silberstein R, Sirca C, Spano D, Steinbrecher R, Stevens RM, Sturtevant C, Suyker A, Tagesson T, Takanashi S, Tang Y, Tapper N, Thom J, Tiedemann F, Tomassucci M, Tuovinen J-P, Urbanski S, Valentini R, van der Molen M, van Gorsel E, van Huissteden K, Varlagin A, Verfaillie J, Vesala T, Vincke C, Vitale D, Vygodskaya N, Walker JP, Walter-Shea E, Wang H, Weber R, Westermann S, Wille C, Wofsy S, Wohlfahrt G, Wolf S, Woodgate W, Zampedri R, Zhang J, Zhou G, Zona D, Agarwal D, Biraud S, Torn M, Papale D, Pastorello G, Trotta C, Canfora E, Chu H, Christianson D, Cheah Y-W, Poindexter C, Chen J, Elbashandy A, Humphrey M, Isaac P, Polidori D, Ribeca A, van Ingen C, Zhang L, Amiro B, Ammann C, Arain MA, Ardö J, Arkebauer T, Arndt SK, Arriga N, Aubinet M, Aurela M, Baldocchi D, Barr A, Beamesderfer E, Marchesini LB, Bergeron O, Beringer J, Bernhofer C, Berveiller D, Billesbach D, Black TA, Blanken PD, Bohrer G, Boike J, Bolstad PV, Bonal D, Bonnefond J-M, Bowling DR, Bracho R, Brodeur J, Brümmer C, Buchmann N, Burban B, Burns SP, Buysse P, Cale P, Cavagna M, Cellier P, Chen S, Chini I, Christensen TR, Cleverly J, Collalti A, Consalvo C, Cook BD, Cook D, Coursolle C, Cremonese E, Curtis PS, D'Andrea E, da Rocha H, Dai X, Davis KJ, De Cinti B, de Grandcourt A, De Ligne A, De Oliveira RC, Delpierre N, Desai AR, Di Bella CM, di Tommasi P, Dolman H, Domingo F, Dong G, Dore S, Duce P, Dufrêne E, Dunn A, Dušek J, Eamus D, Eichelmann U, ElKhidir HAM, Eugster W, Ewenz CM, Ewers B, Famulari D, Fares S, Feigenwinter I, Feitz A, Fensholt R, Filippa G, Fischer M, Frank J, Galvagno M, Gharun M, Gianelle D, Gielen B, Gioli B, Gitelson A, Goded I, Goeckede M, Goldstein AH, Gough CM, Goulden ML, Graf A, Griebel A, Gruening C, Grünwald T, Hammerle A, Han S, Han X, Hansen BU, Hanson C, Hatakka J, He Y, Hehn M, Heinesch B, Hinko-Najera N, Hörtnagl L, Hutley L, Ibrom A, Ikawa H, Jackowicz-Korczynski M, Janouš D, Jans W, Jassal R, Jiang S, Kato T, Khomik M, Klatt J, Knohl A, Knox S, Kobayashi H, Koerber G, Kolle O, Kosugi Y, Kotani A, Kowalski A, Kruijt B, Kurbatova J, Kutsch WL, Kwon H, Launiainen S, Laurila T, Law B, Leuning R, Li Y, Liddell M, Limousin J-M, Lion M, Liska AJ, Lohila A, López-Ballesteros A, López-Blanco E, Loubet B, Loustau D, Lucas-Moffat A, Lüers J, Ma S, Macfarlane C, Magliulo V, Maier R, Mammarella I, Manca G, Marcolla B, Margolis HA, Marras S, Massman W, Mastepanov M, Matamala R, Matthes JH, Mazzenga F, McCaughey H, McHugh I, McMillan AMS, Merbold L, Meyer W, Meyers T, Miller SD, Minerbi S, Moderow U, Monson RK, Montagnani L, Moore CE, Moors E, Moreaux V, Moureaux C, Munger JW, Nakai T, Neirynck J, Nesic Z, Nicolini G, Noormets A, Northwood M, Nosetto M, Nouvellon Y, Novick K, Oechel W, Olesen JE, Ourcival J-M, Papuga SA, Parmentier F-J, Paul-Limoges E, Pavelka M, Peichl M, Pendall E, Phillips RP, Pilegaard K, Pirk N, Posse G, Powell T, Prasse H, Prober SM, Rambal S, Rannik Ü, Raz-Yaseef N, Reed D, de Dios VR, Restrepo-Coupe N, Reverter BR, Roland M, Sabbatini S, Sachs T, Saleska SR, Sánchez-Cañete EP, Sanchez-Mejia ZM, Schmid HP, Schmidt M, Schneider K, Schrader F, Schroder I, Scott RL, Sedlák P, Serrano-Ortíz P, Shao C, Shi P, Shironya I, Siebicke L, Šigut L, Silberstein R, Sirca C, Spano D, Steinbrecher R, Stevens RM, Sturtevant C, Suyker A, Tagesson T, Takanashi S, Tang Y, Tapper N, Thom J, Tiedemann F, Tomassucci M, Tuovinen J-P, Urbanski S, Valentini R, van der Molen M, van Gorsel E, van Huissteden K, Varlagin A, Verfaillie J, Vesala T, Vincke C, Vitale D, Vygodskaya N, Walker JP, Walter-Shea E, Wang H, Weber R, Westermann S, Wille C, Wofsy S, Wohlfahrt G, Wolf S, Woodgate W, Zampedri R, Zhang J, Zhou G, Zona D, Agarwal D, Biraud S, Torn M, and Papale D

Abstract

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.

Published
2020

30. Evidence for soil water control on carbon and water dynamics in European forests during the extremely dry year: 2003

Author

Granier, A., Reichstein, M., Bréda, N., Janssens, I.A., Falge, E., Ciais, P., Grünwald, T., Aubinet, M., Berbigier, P., Bernhofer, C., Buchmann, N., Facini, O., Grassi, G., Heinesch, B., Ilvesniemi, H., Keronen, P., Knohl, A., Köstner, B., Lagergren, F., Lindroth, A., Longdoz, B., Loustau, D., Mateus, J., Montagnani, L., Nys, C., Moors, E., Papale, D., Peiffer, M., Pilegaard, K., Pita, G., Pumpanen, J., Rambal, S., Rebmann, C., Rodrigues, A., Seufert, G., Tenhunen, J., Vesala, T., and Wang, Q.

Published
2007
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31. Partitioning European grassland net ecosystem CO 2 exchange into gross primary productivity and ecosystem respiration using light response function analysis

Author

Gilmanov, T.G., Soussana, J.F., Aires, L., Allard, V., Ammann, C., Balzarolo, M., Barcza, Z., Bernhofer, C., Campbell, C.L., Cernusca, A., Cescatti, A., Clifton-Brown, J., Dirks, B.O.M., Dore, S., Eugster, W., Fuhrer, J., Gimeno, C., Gruenwald, T., Haszpra, L., Hensen, A., Ibrom, A., Jacobs, A.F.G., Jones, M.B., Lanigan, G., Laurila, T., Lohila, A., G.Manca, Marcolla, B., Nagy, Z., Pilegaard, K., Pinter, K., Pio, C., Raschi, A., Rogiers, N., Sanz, M.J., Stefani, P., Sutton, M., Tuba, Z., Valentini, R., Williams, M.L., and Wohlfahrt, G.

Published
2007
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34. Europe-wide reduction in primary productivity caused by the heat and drought in 2003

Author

Ciais, Ph., Reichstein, M., Viovy, N., Granier, A., Ogée, J., Allard, V., Aubinet, M., Buchmann, N., Bernhofer, Chr., Carrara, A., Chevallier, F., De Noblet, N., Friend, A. D., Friedlingstein, P., Grünwald, T., Heinesch, B., Keronen, P., Knohl, A., Krinner, G., Loustau, D., Manca, G., Matteucci, G., Miglietta, F., Ourcival, J. M., Papale, D., Pilegaard, K., Rambal, S., Seufert, G., Soussana, J. F., Sanz, M. J., Schulze, E. D., Vesala, T., and Valentini, R.

Published
2005

35. PEAT-CLSM: A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model

Author

Bechtold, M. (M.), De Lannoy, G.J.M. (G. J.M.), Koster, R.D. (R. D.), Reichle, R.H. (R. H.), Mahanama, S.P. (S. P.), Bleuten, W. (W.), Bourgault, M.A. (M. A.), Brümmer, C. (C.), Burdun, I. (I.), Desai, A.R. (A. R.), Devito, K. (K.), Grünwald, T. (T.), Grygoruk, M. (M.), Humphreys, E. (Elyn), Klatt, J. (J.), Kurbatova, J. (J.), Lohila, A. (A.), Munir, T.M. (T. M.), Nilsson, M.B. (M. B.), Price, J.S. (J. S.), Röhl, M. (M.), Schneider, A. (A.), Tiemeyer, B. (B.), Bechtold, M. (M.), De Lannoy, G.J.M. (G. J.M.), Koster, R.D. (R. D.), Reichle, R.H. (R. H.), Mahanama, S.P. (S. P.), Bleuten, W. (W.), Bourgault, M.A. (M. A.), Brümmer, C. (C.), Burdun, I. (I.), Desai, A.R. (A. R.), Devito, K. (K.), Grünwald, T. (T.), Grygoruk, M. (M.), Humphreys, E. (Elyn), Klatt, J. (J.), Kurbatova, J. (J.), Lohila, A. (A.), Munir, T.M. (T. M.), Nilsson, M.B. (M. B.), Price, J.S. (J. S.), Röhl, M. (M.), Schneider, A. (A.), and Tiemeyer, B. (B.)

Abstract

Peatlands are poorly represented in global Earth system modeling frameworks. Here we add a peatland-specific land surface hydrology module (PEAT-CLSM) to the Catchment Land Surface Model (CLSM) of the NASA Goddard Earth Observing System (GEOS) framework. The amended TOPMODEL approach of the original CLSM that uses topography characteristics to model catchment processes is discarded, and a peatland-specific model concept is realized in its place. To facilitate its utilization in operational GEOS efforts, PEAT-CLSM uses the basic structure of CLSM and the same global input data. Parameters used in PEAT-CLSM are based on literature data. A suite of CLSM and PEAT-CLSM simulations for peatland areas between 40°N and 75°N is presented and evaluated against a newly compiled data set of groundwater table depth and eddy covariance observations of latent and sensible heat fluxes in natural and seminatural peatlands. CLSM's simulated groundwater tables are too deep and variable, whereas PEAT-CLSM simulates a mean groundwater table depth of −0.20 m (snow-free unfrozen period) with moderate temporal fluctuations (standard deviation of 0.10 m), in significantly better agreement with in situ observations. Relative to an operational CLSM version that simply includes peat as a soil class, the temporal correlation coefficient is increased on average by 0.16 and reaches 0.64 for bogs and 0.66 for fens when driven with global atmospheric forcing data. In PEAT-CLSM, runoff is increased on average by 38% and evapotranspiration is reduced by 19%. The evapotranspiration reduction constitutes a significant improvement relative to eddy covariance measurements.

Published
2019
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36. Estimates of the Annual Net Carbon and Water Exchange of Forests: The EUROFLUX Methodology

Author

Aubinet, M., primary, Grelle, A., additional, Ibrom, A., additional, Rannik, Ü., additional, Moncrieff, J., additional, Foken, T., additional, Kowalski, A.S., additional, Martin, P.H., additional, Berbigier, P., additional, Bernhofer, Ch., additional, Clement, R., additional, Elbers, J., additional, Granier, A., additional, Grünwald, T., additional, Morgenstern, K., additional, Pilegaard, K., additional, Rebmann, C., additional, Snijders, W., additional, Valentini, R., additional, and Vesala, T., additional

Published
1999
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37. Respiration as the main determinant of carbon balance in European forests

Author

Valentini, R., Matteucci, G., Dolman, A. J., Schulze, E.-D., Rebmann, C., Moors, E. J., Granier, A., Gross, P., Jensen, N. O., Pilegaard, K., Lindroth, A., Grelle, A., Bernhofer, C., Grünwald, T., Aubinet, M., Ceulemans, R., Kowalski, A. S., Vesala, T., Rannik, Ü, Berbigier, P., Loustau, D., Gumundsson, J., Thorgeirsson, H., Ibrom, A., Morgenstern, K., Clement, R., Moncrieff, J., Montagnani, L., Minerbi, S., and Jarvis, P. G.

Published
2000

38. PEAT‐CLSM: A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model

Author

Bechtold, M., primary, De Lannoy, G. J. M., additional, Koster, R. D., additional, Reichle, R. H., additional, Mahanama, S. P., additional, Bleuten, W., additional, Bourgault, M. A., additional, Brümmer, C., additional, Burdun, I., additional, Desai, A. R., additional, Devito, K., additional, Grünwald, T., additional, Grygoruk, M., additional, Humphreys, E. R., additional, Klatt, J., additional, Kurbatova, J., additional, Lohila, A., additional, Munir, T. M., additional, Nilsson, M. B., additional, Price, J. S., additional, Röhl, M., additional, Schneider, A., additional, and Tiemeyer, B., additional

Published
2019
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39. ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales

Author

Qiu, C. (Chunjing), Zhu, D. (Dan), Ciais, P. (Philippe), Guenet, B. (Bertrand), Krinner, G. (Gerhard), Peng, S. (Shushi), Aurela, M. (Mika), Bernhofer, C. (Christian), Brümmer, C. (Christian), Bret-Harte, S. (Syndonia), Chu, H. (Housen), Chen, J. (Jiquan), Desai, A.R. (Ankur R.), Dušek, J. (Jǐrí), Euskirchen, E.S. (Eugénie S.), Fortuniak, K. (Krzysztof), Flanagan, L.B. (Lawrence B.), Friborg, T. (Thomas), Grygoruk, M. (Mateusz), Gogo, S. (Sébastien), Grünwald, T. (Thomas), Hansen, B.U. (Birger U.), Holl, D. (David), Humphreys, E. (Elyn), Hurkuck, M. (Miriam), Kiely, G. (Gerard), Klatt, J. (Janina), Kutzbach, L. (Lars), Largeron, C. (Chloé), Laggoun-Défarge, F. (Fatima), Lund, M. (Magnus), Lafleur, P.M. (Peter M.), Li, X. (Xuefei), Mammarella, I. (Ivan), Merbold, L. (Lutz), Nilsson, M.B. (Mats B.), Olejnik, J. (Janusz), Ottosson-Löfvenius, M. (Mikaell), Oechel, W. (Walter), Parmentier, F.-J.W. (Frans-Jan W.), Peichl, M. (Matthias), Pirk, N. (Norbert), Peltola, O. (Olli), Pawlak, W. (Włodzimierz), Rasse, D. (Daniel), Rinne, J. (Janne), Shaver, G. (Gaius), Peter Schmid, H. (Hans), Sottocornola, M. (Matteo), Steinbrecher, R. (Rainer), Sachs, T. (Torsten), Urbaniak, M. (Marek), Zona, D. (Donatella), Ziemblinska, K. (Klaudia), Qiu, C. (Chunjing), Zhu, D. (Dan), Ciais, P. (Philippe), Guenet, B. (Bertrand), Krinner, G. (Gerhard), Peng, S. (Shushi), Aurela, M. (Mika), Bernhofer, C. (Christian), Brümmer, C. (Christian), Bret-Harte, S. (Syndonia), Chu, H. (Housen), Chen, J. (Jiquan), Desai, A.R. (Ankur R.), Dušek, J. (Jǐrí), Euskirchen, E.S. (Eugénie S.), Fortuniak, K. (Krzysztof), Flanagan, L.B. (Lawrence B.), Friborg, T. (Thomas), Grygoruk, M. (Mateusz), Gogo, S. (Sébastien), Grünwald, T. (Thomas), Hansen, B.U. (Birger U.), Holl, D. (David), Humphreys, E. (Elyn), Hurkuck, M. (Miriam), Kiely, G. (Gerard), Klatt, J. (Janina), Kutzbach, L. (Lars), Largeron, C. (Chloé), Laggoun-Défarge, F. (Fatima), Lund, M. (Magnus), Lafleur, P.M. (Peter M.), Li, X. (Xuefei), Mammarella, I. (Ivan), Merbold, L. (Lutz), Nilsson, M.B. (Mats B.), Olejnik, J. (Janusz), Ottosson-Löfvenius, M. (Mikaell), Oechel, W. (Walter), Parmentier, F.-J.W. (Frans-Jan W.), Peichl, M. (Matthias), Pirk, N. (Norbert), Peltola, O. (Olli), Pawlak, W. (Włodzimierz), Rasse, D. (Daniel), Rinne, J. (Janne), Shaver, G. (Gaius), Peter Schmid, H. (Hans), Sottocornola, M. (Matteo), Steinbrecher, R. (Rainer), Sachs, T. (Torsten), Urbaniak, M. (Marek), Zona, D. (Donatella), and Ziemblinska, K. (Klaudia)

Abstract

Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5° grid cell, defined from a g

Published
2018
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40. Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe’s terrestrial ecosystems: a review

Author

Franz, D., Acosta, M., Altimir, N., Arriga, N., Arrouays, D., Aubinet, M., Aurela, M., Ayres, E., López-Ballesteros, A., Barbaste, M., Berveiller, D., Biraud, S., Boukir, H., Brown, T., Brümmer, C., Buchmann, N., Burba, G., Carrara, A., Cescatti, A., Ceschia, E., Clement, R., Cremonese, E., Crill, E., Darenova, E., Dengel, S., D’Odorico, P., Filippa, G., Fleck, S., Fratini, G., Fuß, R., Gielen, B., Gogo, S., Grace, J., Graf, A., Grelle, A., Gross, P., Grünwald, T., Haapanala, S., Hehn, M., Heinesch, B., Heiskanen, J., Herbst, M., Herschlein, C., Hörtnagl, L., Hufkens, K., Ibrom, A., Jolivet, C., Joly, L., Jones, M., Migliavacca, M., Mölder, M., Montagnani, L., Moureaux, C., Nelson, D., Nemitz, E., Nicolini, G., Nilsson, M.B., Op de Beeck, M., Osborne, B., Löfvenius, M.O., Pavelka, M., Peichl, M., Peltola, O., Pihlatie, M., Pitacco, A., Pokorný, R., Pumpanen, J., Ratié, C., Rebmann, Corinna, Roland, M., Sabbatini, S., Saby, N.P.A., Saunders, M., Schmid, H.P., Schrumpf, M., Sedlák, P., Serrano Ortiz, P., Siebicke, L., Šigut, L., Silvennoinen, H., Simioni, G., Skiba, U., Sonnentag, O., Soudani, K., Soulé, P., Steinbrecher, R., Tallec, T., Thimonier, A., Tuittila, E.-S., Tuovinen, J.-P., Vestin, P., Vincent, G., Vincke, C., Vitale, D., Waldner, P., Weslien, P., Wingate, L., Wohlfahrt, G., Zahniser, M., Vesala, T., Franz, D., Acosta, M., Altimir, N., Arriga, N., Arrouays, D., Aubinet, M., Aurela, M., Ayres, E., López-Ballesteros, A., Barbaste, M., Berveiller, D., Biraud, S., Boukir, H., Brown, T., Brümmer, C., Buchmann, N., Burba, G., Carrara, A., Cescatti, A., Ceschia, E., Clement, R., Cremonese, E., Crill, E., Darenova, E., Dengel, S., D’Odorico, P., Filippa, G., Fleck, S., Fratini, G., Fuß, R., Gielen, B., Gogo, S., Grace, J., Graf, A., Grelle, A., Gross, P., Grünwald, T., Haapanala, S., Hehn, M., Heinesch, B., Heiskanen, J., Herbst, M., Herschlein, C., Hörtnagl, L., Hufkens, K., Ibrom, A., Jolivet, C., Joly, L., Jones, M., Migliavacca, M., Mölder, M., Montagnani, L., Moureaux, C., Nelson, D., Nemitz, E., Nicolini, G., Nilsson, M.B., Op de Beeck, M., Osborne, B., Löfvenius, M.O., Pavelka, M., Peichl, M., Peltola, O., Pihlatie, M., Pitacco, A., Pokorný, R., Pumpanen, J., Ratié, C., Rebmann, Corinna, Roland, M., Sabbatini, S., Saby, N.P.A., Saunders, M., Schmid, H.P., Schrumpf, M., Sedlák, P., Serrano Ortiz, P., Siebicke, L., Šigut, L., Silvennoinen, H., Simioni, G., Skiba, U., Sonnentag, O., Soudani, K., Soulé, P., Steinbrecher, R., Tallec, T., Thimonier, A., Tuittila, E.-S., Tuovinen, J.-P., Vestin, P., Vincent, G., Vincke, C., Vitale, D., Waldner, P., Weslien, P., Wingate, L., Wohlfahrt, G., Zahniser, M., and Vesala, T.

Abstract

Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.

Published
2018

41. Timing of the compensation of winter respiratory carbon losses provides explanatory power for net ecosystem productivity of forests

Author

Haeni, M., Zweifel, R., Eugster, W., Gessler, A., Zielis, S., Bernhofer, C., Carrara, A., Grünwald, T., Havránková, K., Heinesch, B., Herbst, M., Ibrom, Andreas, Knohl, A., Lagergren, F., Law, B. E., Marek, M., Matteucci, G., McCaughey, J. H., Minerbi, S., Montagnani, L., Moors, E., Olejnik, J., Pavelka, M., Pilegaard, Kim, Pita, G., Rodrigues, A., Sanz Sánchez, M. J., Schelhaas, M.-J., Urbaniak, M., Valentini, R., Varlagin, A., Vesala, T., Vincke, C., Wu, J., and Buchmann, N.

Subjects
SDG 13 - Climate Action
Abstract

Accurate predictions of net ecosystem productivity (NEPc) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEPc (e.g. climate, nutrients) are not entirely understood yet, particularly when considering the influence of past periods.Here we explored the explanatory power of the compensation day (cDOY) —defined as the day of year when winter net carbon losses are compensated by spring assimilation— for NEPc in 26 forests in Europe, North America, and Australia, using different NEPc integration methods.We found cDOY to be a particularly powerful predictor for NEPc of temperate evergreen needle-leaf forests (R2 = 0.58) and deciduous broadleaf forests (R2 = 0.68). In general, the latest cDOY correlated with the lowest NEPc. The explanatory power of cDOY depended on the integration method for NEPc, forest type, and whether the site had a distinct winter net respiratory carbon loss or not. The integration methods starting in autumn led to better predictions of NEPc from cDOY then the classical calendar method starting at January 1. Limited explanatory power of cDOY for NEPc was found for warmer sites with no distinct winter respiratory loss period.Our findings highlight the importance of the influence of winter processes and the delayed responses of previous seasons’ climatic conditions on current year's NEPc. Such carry-over effects may contain information from climatic conditions, carbon storage levels and hydraulic traits of several years back in time.

Published
2017

42. Winter respiratory C losses provide explanatory power for net ecosystem productivity

Author

Haeni, M., Zweifel, R., Eugster, W., Gessler, A., Zielis, S., Bernhofer, C., Carrara, A., Grünwald, T., Havránková, K., Heinesch, B., Marek, M., Moors, E., Schelhaas, M.J., and Buchmann, N.

Subjects
Climate Resilience, carbon sink, Klimaatbestendigheid, carbon source, eddy covariance, Vegetatie, Bos- en Landschapsecologie, Vegetation, Forest and Landscape Ecology, CO exchange, growing season length, winter respiration
Abstract

Accurate predictions of net ecosystem productivity (NEPc) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEPc (e.g., climate and nutrients) are not entirely understood yet, particularly when considering the influence of past periods. Here we explored the explanatory power of the compensation day (cDOY)—defined as the day of year when winter net carbon losses are compensated by spring assimilation—for NEPc in 26 forests in Europe, North America, and Australia, using different NEPc integration methods. We found cDOY to be a particularly powerful predictor for NEPc of temperate evergreen needleleaf forests (R2 = 0.58) and deciduous broadleaf forests (R2 = 0.68). In general, the latest cDOY correlated with the lowest NEPc. The explanatory power of cDOY depended on the integration method for NEPc, forest type, and whether the site had a distinct winter net respiratory carbon loss or not. The integration methods starting in autumn led to better predictions of NEPc from cDOY then the classical calendar method starting 1 January. Limited explanatory power of cDOY for NEPc was found for warmer sites with no distinct winter respiratory loss period. Our findings highlight the importance of the influence of winter processes and the delayed responses of previous seasons' climatic conditions on current year's NEPc. Such carry-over effects may contain information from climatic conditions, carbon storage levels, and hydraulic traits of several years back in time.

Published
2017

43. Atmospheric deposition, CO₂, and change in the land carbon sink

Author

Fernández-Martínez, Marcos, Vicca, Sara, Peñuelas, Josep, Janssens, Ivan, Ciais, Philippe, Obersteiner, Michael, Bartrons Vilamala, Mireia, Sardans i Galobart, Jordi, Verger, Aleixandre, Canadell, Josep G., Chevallier, Frédéric, Wang, Xuhui, Bernhofer, C., Curtis, P. S., Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, Andreas, Knohl, A., Laurila, T., Law, B. E., Limousin, Jean-Marc, Longdoz, B., Loustau, Denis, Mammarella, I., Matteucci, G., Monson, R. K., Montagnani, L., Moors, E. J., Munger, J. W., Papale, D., and Piao, S. L.

Subjects
Climate-change ecology, Carbon cycle, Forest ecology
Abstract

Concentrations of atmospheric carbon dioxide (CO₂) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO₂ was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO₂-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO₂, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling.

Published
2017

44. Atmospheric deposition, CO2, and change in the land carbon sink

Author

Fernández-Martínez, M., Vicca, S., Janssens, I.A., Ciais, P., Obersteiner, M., Bartrons, M., Sardans, J., Verger, A., Canadell, J.G., Chevallier, F., Wang, X., Bernhofer, C., Curtis, P.S., Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, A., Knohl, A., Laurila, T., Law, B.E., Limousin, J.M., Longdoz, B., Loustau, D., Mammarella, I., Matteucci, G., Monson, R.K., Montagnani, L., Moors, E.J., Munger, J.W., Papale, D., Piao, S.L., Peñuelas, J., Fernández-Martínez, M., Vicca, S., Janssens, I.A., Ciais, P., Obersteiner, M., Bartrons, M., Sardans, J., Verger, A., Canadell, J.G., Chevallier, F., Wang, X., Bernhofer, C., Curtis, P.S., Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, A., Knohl, A., Laurila, T., Law, B.E., Limousin, J.M., Longdoz, B., Loustau, D., Mammarella, I., Matteucci, G., Monson, R.K., Montagnani, L., Moors, E.J., Munger, J.W., Papale, D., Piao, S.L., and Peñuelas, J.

Abstract

Concentrations of atmospheric carbon dioxide (CO2) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO2-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO2, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling.

Published
2017

45. Atmospheric deposition, CO2, and change in the land carbon sink

Author

Martinez-Fernandez, Cristina, Vicca, Sara, Janssens, Ivan A., Ciais, P., Obersteiner, M, Bartrons, M, Sardans, J., Verger, A, Canadell, J G, Chevallier, F., Wang, X, Bernhofer, C., Curtis, Peter S, Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, Andreas, Knohl, A., Laurila, T., Law, Beverly E., Limousin, J M, Longdoz, B., Loustau, D., Mammarella, I., Matteucci, G., Monson, Russell K, Montagnani, L., Moors, Eddy J., Munger, J William, Papale, D., Piao, S L, Penuelas, J., Martinez-Fernandez, Cristina, Vicca, Sara, Janssens, Ivan A., Ciais, P., Obersteiner, M, Bartrons, M, Sardans, J., Verger, A, Canadell, J G, Chevallier, F., Wang, X, Bernhofer, C., Curtis, Peter S, Gianelle, D., Grünwald, T., Heinesch, B., Ibrom, Andreas, Knohl, A., Laurila, T., Law, Beverly E., Limousin, J M, Longdoz, B., Loustau, D., Mammarella, I., Matteucci, G., Monson, Russell K, Montagnani, L., Moors, Eddy J., Munger, J William, Papale, D., Piao, S L, and Penuelas, J.

Abstract

Concentrations of atmospheric carbon dioxide (CO2) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO2-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO2, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling.

Published
2017

46. Atmospheric deposition, CO2, and change in the land carbon sink

Author

Fernández-Martínez, M., primary, Vicca, S., additional, Janssens, I. A., additional, Ciais, P., additional, Obersteiner, M., additional, Bartrons, M., additional, Sardans, J., additional, Verger, A., additional, Canadell, J. G., additional, Chevallier, F., additional, Wang, X., additional, Bernhofer, C., additional, Curtis, P. S., additional, Gianelle, D., additional, Grünwald, T., additional, Heinesch, B., additional, Ibrom, A., additional, Knohl, A., additional, Laurila, T., additional, Law, B. E., additional, Limousin, J. M., additional, Longdoz, B., additional, Loustau, D., additional, Mammarella, I., additional, Matteucci, G., additional, Monson, R. K., additional, Montagnani, L., additional, Moors, E. J., additional, Munger, J. W., additional, Papale, D., additional, Piao, S. L., additional, and Peñuelas, J., additional

Published
2017
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47. Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites

Author

Collalti, A., Marconi, S., Ibrom, Andreas, Trotta, C., Anav, A., D'andrea, E., Matteucci, G., Montagnani, L., Gielen, B., Mammarella, I., Grünwald, T., Knohl, A., Berninger, F., Zhao, Yichun, Valentini, R., Santini, M., Collalti, A., Marconi, S., Ibrom, Andreas, Trotta, C., Anav, A., D'andrea, E., Matteucci, G., Montagnani, L., Gielen, B., Mammarella, I., Grünwald, T., Knohl, A., Berninger, F., Zhao, Yichun, Valentini, R., and Santini, M.

Abstract

This study evaluates the performances of the new version (v.5.1) of 3D-CMCC Forest Ecosystem Model (FEM) in simulating gross primary productivity (GPP), against eddy covariance GPP data for 10 FLUXNET forest sites across Europe. A new carbon allocation module, coupled with new both phenological and autotrophic respiration schemes, was implemented in this new daily version. Model ability in reproducing timing and magnitude of daily and monthly GPP fluctuations is validated at intra-annual and inter-annual scale, including extreme anomalous seasons. With the purpose to test the 3D-CMCC FEM applicability over Europe without a site-related calibration, the model has been deliberately parametrized with a single set of species-specific parametrizations for each forest ecosystem. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the exception of the two Mediterranean sites. We find that 3D-CMCC FEM tends to better simulate the timing of inter-annual anomalies than their magnitude within measurements' uncertainty. In six of eight sites where data are available, the model well reproduces the 2003 summer drought event. Finally, for three sites we evaluate whether a more accurate representation of forest structural characteristics (i.e. cohorts, forest layers) and species composition can improve model results. In two of the three sites results reveal that model slightly increases its performances although, statistically speaking, not in a relevant way.

Published
2016

48. ORCHIDEE-CROP (v0), a new process-based agro-land surface model: model description and evaluation over Europe

Author

Wu, X., primary, Vuichard, N., additional, Ciais, P., additional, Viovy, N., additional, de Noblet-Ducoudré, N., additional, Wang, X., additional, Magliulo, V., additional, Wattenbach, M., additional, Vitale, L., additional, Di Tommasi, P., additional, Moors, E. J., additional, Jans, W., additional, Elbers, J., additional, Ceschia, E., additional, Tallec, T., additional, Bernhofer, C., additional, Grünwald, T., additional, Moureaux, C., additional, Manise, T., additional, Ligne, A., additional, Cellier, P., additional, Loubet, B., additional, Larmanou, E., additional, and Ripoche, D., additional

Published
2016
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49. Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites

Author

Collalti, A., primary, Marconi, S., additional, Ibrom, A., additional, Trotta, C., additional, Anav, A., additional, D'Andrea, E., additional, Matteucci, G., additional, Montagnani, L., additional, Gielen, B., additional, Mammarella, I., additional, Grünwald, T., additional, Knohl, A., additional, Berninger, F., additional, Zhao, Y., additional, Valentini, R., additional, and Santini, M., additional

Published
2016
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50. Interpreting canopy development and physiology using a European phenology camera network at flux sites

Author

Wingate, L., Ogée, J., Cremonese, E., Filippa, G., Mizunuma, T., Migliavacca, M., Moisy, C., Wilkinson, M., Moureaux, C., Wohlfahrt, G., Hammerle, A., Hörtnagl, L., Gimeno, C., Porcar-Castell, A., Galvagno, M., Nakaji, T., Morison, J., Kolle, O., Knohl, A., Kutsch, W., Kolari, P., Nikinmaa, E., Ibrom, A., Gielen, B., Eugster, W., Balzarolo, M., Papale, D., Klumpp, K., Köstner, B., Grünwald, T., Joffre, R., Ourcival, J.-M., Hellstrom, M., Lindroth, A., George, C., Longdoz, B., Genty, B., Levula, J., Heinesch, B., Sprintsin, M., Yakir, D., Manise, T., Guyon, D., Ahrends, H., Plaza-Aguilar, A., Guan, J. H., Grace, J., Wingate, L., Ogée, J., Cremonese, E., Filippa, G., Mizunuma, T., Migliavacca, M., Moisy, C., Wilkinson, M., Moureaux, C., Wohlfahrt, G., Hammerle, A., Hörtnagl, L., Gimeno, C., Porcar-Castell, A., Galvagno, M., Nakaji, T., Morison, J., Kolle, O., Knohl, A., Kutsch, W., Kolari, P., Nikinmaa, E., Ibrom, A., Gielen, B., Eugster, W., Balzarolo, M., Papale, D., Klumpp, K., Köstner, B., Grünwald, T., Joffre, R., Ourcival, J.-M., Hellstrom, M., Lindroth, A., George, C., Longdoz, B., Genty, B., Levula, J., Heinesch, B., Sprintsin, M., Yakir, D., Manise, T., Guyon, D., Ahrends, H., Plaza-Aguilar, A., Guan, J. H., and Grace, J.

Abstract

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious, there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and croplands, where vegetation and atmosphere CO2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green-up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations, we found that these phenological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall, respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model parameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring `green hump' observed repeatedly in deciduous broadleaf canopies ac

Published
2015

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