Interdecadal variation and trend analysis of the drought occurrence frequency in China
Based on the monthly precipitation data of 160 stations in China from January 1951 to October 2007,the 12-month standardized precipitation index（ISP） was calculated.The statistics of the drought occurrence frequency in different decades was conducted according to the drought classification by ISP value.In addition,the interdecadal trend of the drought occurrence was analyzed by using Mann-Kendall method.The results show that the drought occurred mainly in southern Xinjiang area in the 1950s and in the 1960s a high occurrence frequency center occurred in the area from northern part of Xinjiang to the upper reaches of the Yellow River as well as in Southeast China around the middle and lower reaches of the Yangtze River.In the 1970s,drought events mainly took place in Heilongjiang and Jilin Provinces and the middle reaches of the Yangtze River.In the 1980s,the droughts frequently occurred in two zonal belts which extend from Southwest to South China and from Northwest to North China respectively.In the 1990s,the droughts took place in the area between the Yangtze River and the middle reaches of the Yellow River.During the early 21st century,the drought mainly occurred in the northern part of North China and eastern Inner Mongolia.The Mann-Kendall trend test shows there was an significant drought tendency in northern Xinjiang,eastern Inner Mongolia and the regions extending from the lower reaches of the Yangtze River to Southeast China during the period from the 1950s to 1960s.Northeast China became arid from the 1960s to 1970s.From the 1970s to 1980s,the drought tendency occurred in Shandong Province and the eastern part of Southwest China.The region between the middle reaches of the Yangtze River and the Yellow River became arid from the 1980s to 1990s.From the 1990s to the early 21st century,the drought tendency was significant in the northern part of North China,eastern Inner Mongolia and eastern Heilongjiang.In addition,an abrupt change of high occurrence frequency of droughts appeared around the 1980s.The drought mainly occurred in Northwest China,Northeast China,a region between the Yangtze River and Huaihe River,the middle and lower reaches of the Yangtze River as well as South China during the period from the 1950s to 1970s.However,since the 1980s the high occurrence frequency of droughts has moved to places with low drought occurrence frequency in previous decades.From the 1950s till now,the drought tendency has increased rapidly in eastern Jilin and Heilongjiang areas and a narrow strip which extends southwestward from Hebei to Guizhou,while the drought trend has decreased significantly in Xinjiang,Gansu and Qinghai.
国家科技期刊平台
NSTL
万方数据
维普
