Evapotranspiration amplifies European summer drought

[1] Drought is typically associated with a lack of precipitation, whereas the contribution of evapotranspiration and runoff to drought evolution is not well understood. Here we use unique long-term observations made in four headwater catchments in central and western Europe to reconstruct storage anomalies and study the drivers of storage anomaly evolution during drought. We provide observational evidence for the “drought-paradox” in that region: a consistent and significant increase in evapotranspiration during drought episodes, which acts to amplify the storage anomalies. In contrast, decreases in runoff act to limit storage anomalies. Our findings stress the need for the correct representation of evapotranspiration and runoff processes in drought indices.

[1]  R. D. Jeu,et al.  Evaporation in focus , 2010 .

[2]  Christian Bernhofer,et al.  A decade of carbon, water and energy flux measurements of an old spruce forest at the Anchor Station Tharandt , 2007 .

[3]  Philippe Ciais,et al.  Summer temperatures in Europe and land heat fluxes in observation-based data and regional climate model simulations , 2013, Climate Dynamics.

[4]  P. Ciais,et al.  Europe-wide reduction in primary productivity caused by the heat and drought in 2003 , 2005, Nature.

[5]  S. Seneviratne,et al.  Drought-induced building damages from simulations at regional scale , 2011 .

[6]  E. Wood,et al.  Global Trends and Variability in Soil Moisture and Drought Characteristics, 1950–2000, from Observation-Driven Simulations of the Terrestrial Hydrologic Cycle , 2008 .

[7]  Sonia I. Seneviratne,et al.  Catchments as simple dynamical systems: Experience from a Swiss prealpine catchment , 2010 .

[8]  B. Lloyd‐Hughes,et al.  A drought climatology for Europe , 2002 .

[9]  D. Easterling,et al.  Changes in climate extremes and their impacts on the natural physical environment , 2012 .

[10]  C. C. Brauer,et al.  Anatomy of extraordinary rainfall and flash flood in a Dutch lowland catchment , 2011 .

[11]  M. Aubinet,et al.  Long term carbon dioxide exchange above a mixed forest in the Belgian Ardennes , 2001 .

[12]  A. Dai,et al.  Revisiting the parameterization of potential evaporation as a driver of long‐term water balance trends , 2008 .

[13]  R. Koster,et al.  Assimilation of GRACE terrestrial water storage into a land surface model: Evaluation and potential value for drought monitoring in western and central Europe , 2012 .

[14]  W. Oechel,et al.  Energy balance closure at FLUXNET sites , 2002 .

[15]  R.A.M. de Jeu,et al.  Soil moisture‐temperature coupling: A multiscale observational analysis , 2012 .

[16]  E. Wood,et al.  Little change in global drought over the past 60 years , 2012, Nature.

[17]  S. Seneviratne,et al.  Global intercomparison of 12 land surface heat flux estimates , 2011 .

[18]  S. Seneviratne,et al.  Evaluation of global observations‐based evapotranspiration datasets and IPCC AR4 simulations , 2011 .

[19]  Tomas Vitvar,et al.  Swiss prealpine Rietholzbach research catchment and lysimeter: 32 year time series and 2003 drought event , 2012 .

[20]  S. Seneviratne,et al.  Hot days induced by precipitation deficits at the global scale , 2012, Proceedings of the National Academy of Sciences.

[21]  S. Seneviratne,et al.  Contrasting response of European forest and grassland energy exchange to heatwaves , 2010 .

[22]  H. Verbeeck,et al.  Drought-associated changes in climate and their relevance for ecosystem experiments and models , 2011 .