Response of precipitation recycle ratio(PRR)to global warming in China
The vast territory of China covers a diverse range of climate types and topographical features,provid-ing intricate environmental conditions for the precipitation recycling process.This diversity presents challenges in categorizing and comparing different regions when analyzing the characteristics of precipitation recycle ratio.This study employs an optimized precipitation recycle ratio evaluation model to calculate the precipitation recy-cle ratio in China and investigates its variation characteristics and response to global warming.The findings re-veal that from 1979 to 2020,China experienced notable regional and seasonal differences in precipitation recycle ratios,with the Qinghai-Xizang Plateau exhibiting the highest value.Regions with high values and increase of precipitation recycle ratio were mainly located in the inland humid areas of non-monsoon regions;However,in the arid and semi-arid eastern part of Northwest China,despite a generally lower precipitation recycle ratio,there was a significant upward linear trend.The empirical orthogonal function(EOF)results indicate that the first mode of precipitation recycle ratio is dominated by a negative phase before 2000,shifting to a positive phase afterward.A nine-year moving average of the precipitation recycle ratio suggests an initial increase fol-lowed by a decline.This study categorizes China into four precipitation recycle ratio regions based on the magni-tude of precipitation recycle ratio and its positive or negative climate tendency rate:the precipitation recycle ratio is relatively high and shows an upward trend(Class Ⅰ),the precipitation recycle ratio is relatively high and shows a downward trend(Class Ⅱ),the precipitation recycle ratio is relatively low and shows an upward trend(Class Ⅲ),and the precipitation recycle ratio is relatively low and shows a downward trend(Class Ⅳ).Eight representative regions were selected from the four regions to study the response of precipitation recycle ratio to global warming.In Class Ⅰ and Class Ⅱ,precipitation is mainly affected by local evaporation,while in Class Ⅲ and Class Ⅳ,the relationship between precipitation and external water vapor transport is closer.Within the same class,the response values of internal and external circulation variables to global warming are different.Changes in evaporation and water vapor flux divergence will affect the response strength of the contribution of low-level flow and local evaporation to global warming.Studying the distinct responses of internal and external cyclic variables to global warming across different regions in China can enhance our understanding of climate change impacts and provide a scientific basis for formulating corresponding climate adaptation strategies.
precipitationprecipitation recycle ratio(PRR)global warmingtypical region
NETL
NSTL
万方数据
