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Reduction of ecosystem productivity and respiration during the European summer 2003 climate anomaly: a joint flux tower, remote sensing and modelling analysis |
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| Authors: | M REICHSTEIN P CIAIS D PAPALE R VALENTINI S RUNNING N VIOVY W CRAMER A GRANIER J OGE V ALLARD M AUBINET Chr BERNHOFER N BUCHMANN A CARRARA T GRÜNWALD M HEIMANN B HEINESCH A KNOHL W KUTSCH D LOUSTAU G MANCA G MATTEUCCI F MIGLIETTA JM OURCIVAL K PILEGAARD J PUMPANEN S RAMBAL S SCHAPHOFF G SEUFERT J‐F SOUSSANA M‐J SANZ T VESALA M ZHAO |
| Institution: | Department of Forest Environment and Resources, DISAFRI, University of Tuscia, Viterbo, Italy,;Max Planck Institute for Biogeochemistry, Postfach 10 01 64, 07701 Jena, Germany,;Potsdam Institute for Climate Impact Research, Telegrafenberg C4, D-14473 Potsdam, Germany,;Laboratoire des Sciences du Climat et de l'Environnement, LSCE, 91191, Gif sur Yvette, France,;NTSG, Department of Ecosystem and Conservation Sciences, University of Montana, USA,;Ecologie et Ecophysiologie Forestières, Centre de Nancy, 54280 Champenoux, France,;Functional Ecology and Environmental Physics, Ephyse, INRA, Villenave d'Ornon, France,;Grassland Ecosystem Research, INRA, Site de Crouel. 234, Clermont-Ferrand, F-63039, France,;Facultédes Sciences Agronomiques, Av. de la Facultéd'Agronomie 8, B-5030 Gembloux Belgique,;Department of Meteorology, Institute of Hydrology and-Meteorology, Technische Universität Dresden, D-01062 Dresden, Germany,;Institute of Plant Sciences, Universitätsstrasse 2, ETH Zentrum LFW C56, CH-8092 Zuerich, Switzerland,;Fundacion CEAM C/ Charles Darwin, Parque Tecnologico de Paterna, 46980 Valencia, Spain,;Department. of ESPM, Ecosystem Science Division, University of California, Berkeley, CA, USA,;CNR-ISAFOM, Via Cavour, 4-6 I-87036 Rende (CS), Italy,;IBIMET-CNR, Ple delle Cascine, 18, 50144 Firenze, Italy,;Dream CEFE-CNRS, 1919 route de Mende, 34293 Montpellier, France,;Plant Research Department, RisøNational Laboratory, 4000 Roskilde, Denmark,;Department of Forest Ecology, University of Helsinki, PO Box 24, Helsinki, FN 0014, Finland,;Institute for Environment and Sustainability, Joint Research Center European Commission, TP 280, I-21020 Ispra, Italy,;Department of Physical Sciences, University of Helsinki, PO Box 64, Helsinki, Finland |
| Abstract: | The European CARBOEUROPE/FLUXNET monitoring sites, spatial remote sensing observations via the EOS‐MODIS sensor and ecosystem modelling provide independent and complementary views on the effect of the 2003 heatwave on the European biosphere's productivity and carbon balance. In our analysis, these data streams consistently demonstrate a strong negative anomaly of the primary productivity during the summer of 2003. FLUXNET eddy‐covariance data indicate that the drop in productivity was not primarily caused by high temperatures (‘heat stress’) but rather by limitation of water (drought stress) and that, contrary to the classical expectation about a heat wave, not only gross primary productivity but also ecosystem respiration declined by up to more than to 80 gC m−2 month−1. Anomalies of carbon and water fluxes were strongly correlated. While there are large between‐site differences in water‐use efficiency (WUE, 1–6 kg C kg−1 H2O) here defined as gross carbon uptake divided by evapotranspiration (WUE=GPP/ET), the year‐to‐year changes in WUE were small (<1 g kg−1) and quite similar for most sites (i.e. WUE decreased during the year of the heatwave). Remote sensing data from MODIS and AVHRR both indicate a strong negative anomaly of the fraction of absorbed photosynthetically active radiation in summer 2003, at more than five standard deviations of the previous years. The spatial differentiation of this anomaly follows climatic and land‐use patterns: Largest anomalies occur in the centre of the meteorological anomaly (central Western Europe) and in areas dominated by crops or grassland. A preliminary model intercomparison along a gradient from data‐oriented models to process‐oriented models indicates that all approaches are similarly describing the spatial pattern of ecosystem sensitivity to the climatic 2003 event with major exceptions in the Alps and parts of Eastern Europe, but differed with respect to their interannual variability. |
| Keywords: | carbon balance eddy covariance drought climate change ecosystem productivity ecosystem modelling |