Hydro-climatic fluctuations driven by natural and anthropogenic forcing in China

Thursday, 18 December 2014
Shulei Zhang and Dawen Yang, Tsinghua University, Beijing, China
Hydrological change is one of the most profound parts of global change which is associated with freshwater resources, food security and balance of ecosystem. Its driving factors in the past need to be understood and quantified for projection of future changes and management of water available. Here by applying the Budyko water-energy balance framework, we analyse the hydro-climatic fluctuations at annual scale and their natural and anthropogenic drivers during past fifty years in six major Chinese drainage basins, from south to north, and from natural basins to human-modified basins. Natural forcing here means the fluctuations in precipitation and temperature, and the shift of precipitation from snow towards rain. And we focus on the impact of change in vegetational coverage, agricultural irrigation and water division as anthropogenic effect. By cross-regional comparison and within-region comparison, we explore the spatial variability of the hydro-climatic change and the type and contribution of different driven factors, especially various human modifications, throughout China. This study shows how the complex coupled system of climate, human and eco-hydrology can be described and explored by an effective and simple model and how the water balance constraints of hydrological basins affect water available throughout China and their spatial variability in the past half century.