Changing spatiotemporal patterns of precipitation extremes in China during 2071–2100 based on Earth System Models

摘要

Outputs of five Earth System Models (ESMs) under historical and Representative Concentration Pathways (RCPs) scenarios from the Coupled Model Intercomparison Project phase 5 multimodel data set, as well as daily precipitation from 527 rain gauge stations in China for the period of 1960–2005 are used to investigate the spatiotemporal variations of precipitation extremes over China for 2071–2100. After the evaluation of the indices by the Mann-Whitney U test and the quantile-quantile plot, the weather generator model (WGEN) is used to downscale precipitation extremes. The average of precipitation extremes and values of the 5 and 20 year return periods under RCP26 and RCP85 scenarios are analyzed. Results showed the following: (1) WGEN works well in downscaling extreme heavy precipitation indices and consecutive dry days. (2) The risks of meteorological droughts and floods resulting from extreme long-duration precipitation would decrease in southwest China, but the risks of floods due to extreme heavy precipitation would increase. In north and southeast China, the risks of droughts would decrease, but floods might occur with higher frequencies; (3) The spatiotemporal variations of averages and values of 5 year return period extreme precipitation would be similar, but those of 20 year return period would be a little different: The 20 year consecutive dry days would decrease faster, and the 20 year values of other indices would increase relatively slower. (4) The spatial patterns of changes in precipitation extremes under RCP26 and RCP85 would be similar, but the changes in RCP85 would be intensifying.