Analyzing precipitationsheds to understand the vulnerability of rainfall dependent regions
1Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden
2Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, The Netherlands
3Stockholm Environment Institute, Kräftriket 2b, 10691 Stockholm, Sweden
4Potsdam Institute for Climate Impact Research, Telegrafenberg, Potsdam, Germany
*now at: Keys Consulting Inc., Seattle, WA, USA
Abstract. It is well known that rivers connect upstream and downstream ecosystems within watersheds. Here we describe the concept of precipitationsheds to show how upwind terrestrial evaporation source areas contribute moisture for precipitation to downwind sink regions. We illustrate the importance of upwind land cover in precipitationsheds to sustain precipitation in critically water stressed downwind areas, specifically dryland agricultural areas. We first identify seven regions where rainfed agriculture is particularly vulnerable to reductions in precipitation, and then map their precipitationsheds. We then develop a framework for qualitatively assessing the vulnerability of precipitation for these seven agricultural regions. We illustrate that the sink regions have varying degrees of vulnerability to changes in upwind evaporation rates depending on the extent of the precipitationshed, source region land use intensity and expected land cover changes in the source region.