caa a22 4500 528787454 20190104030322.0 cr unu---uuuuu 180924s2014 xx s 000 0 eng 10.3929/ethz-b-000100524 doi 10.5194/bg-11-2909-2014 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/100524 Extreme events in gross primary production: A characterization across continents [Elektronische Daten] [Jakob Zscheischler, id_orcid 0000-0001-6045-1629, Markus Reichstein, Markus Reichstein, Anja Rammig, Enrico Tomelleri, Miguel D. Mahecha] Open access ethresearch Climate extremes can affect the functioning of terrestrial ecosystems, for instance via a reduction of the photosynthetic capacity or alterations of respiratory processes. Yet the dominant regional and seasonal effects of hydrometeorological extremes are still not well documented and in the focus of this paper. Specifically, we quantify and characterize the role of large spatiotemporal extreme events in gross primary production (GPP) as triggers of continental anomalies. We also investigate seasonal dynamics of extreme impacts on continental GPP anomalies. We find that the 50 largest positive extremes (i.e., statistically unusual increases in carbon uptake rates) and negative extremes (i.e., statistically unusual decreases in carbon uptake rates) on each continent can explain most of the continental variation in GPP, which is in line with previous results obtained at the global scale. We show that negative extremes are larger than positive ones and demonstrate that this asymmetry is particularly strong in South America and Europe. Our analysis indicates that the overall impacts and the spatial extents of GPP extremes are power-law distributed with exponents that vary little across continents. Moreover, we show that on all continents and for all data sets the spatial extents play a more important role for the overall impact of GPP extremes compared to the durations or maximal GPP. An analysis of possible causes across continents indicates that most negative extremes in GPP can be attributed clearly to water scarcity, whereas extreme temperatures play a secondary role. However, for Europe, South America and Oceania we also identify fire as an important driver. Our findings are consistent with remote sensing products. An independent validation against a literature survey on specific extreme events supports our results to a large extent. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Zscheischler Jakob joint author id_orcid 0000-0001-6045-1629 joint author Reichstein Markus joint author Rammig Anja joint author Tomelleri Enrico joint author Mahecha Miguel D. joint author Biogeosciences Göttingen : Copernicus 11 (11), pp. 2909-2924 http://hdl.handle.net/20.500.11850/100524 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/100524 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Zscheischler Jakob joint author ETHRESEARCH 700 -- id_orcid 0000-0001-6045-1629 joint author ETHRESEARCH 700 1- Reichstein Markus joint author ETHRESEARCH 700 1- Rammig Anja joint author ETHRESEARCH 700 1- Tomelleri Enrico joint author ETHRESEARCH 700 1- Mahecha Miguel D. joint author ETHRESEARCH 773 0- Biogeosciences Göttingen : Copernicus 11 (11), pp. 2909-2924 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access