The occurrence of wet and dry growing seasons in water-limited regions remains poorly understood, partly due to the complex role that these regions play in the genesis of their own rainfall. This limits the predictability of global carbon and water budgets, and hinders the regional management of natural resources. Using novel satellite observations and atmospheric trajectory modelling, we unravel the origin and immediate drivers of growing-season precipitation, and the extent to which ecoregions themselves contribute to their own supply of rainfall. Results show that persistent anomalies in growing-season precipitation—and subsequent biomass anomalies—are caused by a complex interplay of land and ocean evaporation, air circulation and local atmospheric stability changes. For regions such as the Kalahari and Australia, the volumes of moisture recycling decline in dry years, providing a positive feedback that intensifies dry conditions. However, recycling ratios increase up to 40%, pointing to the crucial role of these regions in generating their own supply of rainfall; transpiration in periods of water stress allows vegetation to partly offset the decrease in regional precipitation. Findings highlight the need to adequately represent vegetation–atmosphere feedbacks in models to predict biomass changes and to simulate the fate of water-limited regions in our warming climate.
Department of Earth Sciences, VU University Amsterdam, Amsterdam, 1081-HV, Amsterdam, The Netherlands;Laboratory of Hydrology and Water Management, Ghent University, B-9000, Ghent, Belgium;EPhysLab, Department of Applied Physics, Faculty of Science, Universidad de Vigo, ES-32004, Ourense, Spain;Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM 87545, USA;Laboratory of Hydrology and Water Management, Ghent University, B-9000, Ghent, Belgium;Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, 1040, Austria;Laboratory of Hydrology and Water Management, Ghent University, B-9000, Ghent, Belgium;ARC Centre of Excellence for Climate Systems Science and Climate Change Research Centre, University of New South Wales, Sydney, 2052, Australia;School of Geography and Remote Sensing, Nanjing University of Information Science and Technology, Nanjing, 210044, People’s Republic of China;Hydrology and Quantitative Water Management Group, Wageningen University, 6708-PB, Wageningen, The Netherlands;Department of Earth Sciences, VU University Amsterdam, Amsterdam, 1081-HV, Amsterdam, The Netherlands;Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA;EPhysLab, Department of Applied Physics, Faculty of Science, Universidad de Vigo, ES-32004, Ourense, Spain
Recommended Citation:
Diego G Miralles,Raquel Nieto,Nathan G McDowell,et al. Contribution of water-limited ecoregions to their own supply of rainfall[J]. Environmental Research Letters,2016-01-01,11(12)