Copula-based spatio-temporal patterns of precipitation extremes in China

Daily precipitation data from 590 stations in China covering a period of 19602005 are analysed using copulas, the modified MannKendall (MK) trend test and linear regression. Changing characteristics of eight precipitation indices are investigated in both time and space. Results indicate that (1) the regions west of 100 degrees E, particularly northwest China, exhibit a wetting tendency as reflected by increasing/decreasing number of consecutive rain/non-rain days; (2) the drying tendency is observed mainly in the regions covered by the Yellow River basin, the Huaihe River basin, and the Haihe River basin, and relatively moderate changes in precipitation indices are found in northeast China; (3) precipitation extremes are intensifying in the regions east of 100 degrees E, particularly in case of south China, specifically the lower Yangtze River basin, the southeast rivers and the Pearl River basin. The intensification of precipitation extremes in south China is mirrored mainly by the decreasing number of rain days and increasing number of consecutive non-rain days. Besides an increasing percentage of P90 to the annual total precipitation, (4) the intensification of precipitation extremes has the potential to increase the probability of occurrence of natural hazards, particularly floods and droughts. The spatial distribution of flood- and drought-affected crop areas is in agreement with that of precipitation extremes, showing considerable impacts of precipitation extremes on meteor-hydrological hazards. An increasing number of consecutive non-rain days in south China will cause a higher risk of droughts. The regions east of 100 degrees E are heavily populated and are economically developed. Food security, water security, and sustainable socioeconomy in China urgently call for effective water resource management policy. Copyright (c) 2012 Royal Meteorological Society