Spatiotemporal shifts in key hydrological variables and dominant factors over China
Shanlei Sun, Zaoying Bi, Shujia Zhou, Hongzhou Wang, Qingqing Li, Yi Liu, Guojie Wang, Shijie Li, Haishan Chen, Yang Zhou
Abstract
Abstract Quantitatively and physically understanding changes in land surface hydrology is a hot topic in the hydro‐meteorological research, especially over China with high population density but uneven distribution of water resources. Therefore, the spatiotemporal dynamics (i.e., the 1980s [1981–1990] and 1990s [1991–2000] relative to the baseline of 1961–1980) in evapotranspiration ( ET ) and streamflow/runoff ( Q ) were examined across 426 hydrological divisions (HDs) of China. Both the 1980s and 1990s ET decreased over roughly 50% HDs mainly in the central and southeast parts of China, while the 1980s (1990s) Q decreased over slightly higher than 50% (63%) HDs generally in north and southwest China (the central and north parts of China). Relative to the 1980s, more HDs had strong changes in ET and Q in 1990s. Based on the separated contributions of precipitation ( P ), reference ET and Budyko‐type equation parameter n (an integrated variable of catchment property) to ET and Q changes, we found that in 1980s and 1990s, n dominated ET changes over about 60% HDs mainly in the south, with the dominant of P around 35% HDs generally in the north and northeast, while for Q changes, nearly 60% (slightly less than 40%) HDs were dominated by n ( P ). Moreover, the dominants for ET ( Q ) changes have shifted from 1980s to 1990s over 36% (45%) HDs, mainly changing from P to n . This study provides a framework for quantitatively understanding land surface hydrological dynamics from the perspectives of climatic and physiographic controls over regions.