Journal article
Contrasting response of European forest and grassland energy exchange to heatwaves
Swiss Federal Institute of Technology Zurich1
Wind Energy Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark2
Risø National Laboratory for Sustainable Energy, Technical University of Denmark3
Edmund Mach Foundation4
University of Antwerp5
National Institute for Agronomic Research6
Free University of Bozen-Bolzano7
University of Liege8
University of Innsbruck9
MeteoSwiss10
Max Planck Institute11
Alterra12
Laboratoire des Sciences de Climat et de l’Environnement13
KNMI14
Agroscope15
Dresden University of Technology16
Meteorology, Wind Energy Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark17
...and 7 moreRecent European heatwaves have raised interest in the impact of land cover conditions on temperature extremes. At present, it is believed that such extremes are enhanced by stronger surface heating of the atmosphere, when soil moisture content is below average. However, the impact of land cover on the exchange of water and energy and the interaction of this exchange with the soil water balance during heatwaves is largely unknown.
Here we analyse observations from an extensive network of flux towers in Europe that reveal a difference between the temporal responses of forest and grassland ecosystems during heatwaves. We find that initially, surface heating is twice as high over forest than over grassland. Over grass, heating is suppressed by increased evaporation in response to increased solar radiation and temperature.
Ultimately, however, this process accelerates soil moisture depletion and induces a critical shift in the regional climate system that leads to increased heating. We propose that this mechanism may explain the extreme temperatures in August 2003. We conclude that the conservative water use of forest contributes to increased temperatures in the short term, but mitigates the impact of the most extreme heat and/or long-lasting events.
Language: | English |
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Publisher: | Nature Publishing Group UK |
Year: | 2010 |
Pages: | 722-727 |
ISBN: | 0875900720 , 1118664280 , 9780875900728 and 9781118664285 |
ISSN: | 17520908 and 17520894 |
Types: | Journal article |
DOI: | 10.1038/ngeo950 |
ORCIDs: | Dellwik, Ebba |