Variation characteristics of drought strength,drought frequency,drought days and drought coverage were analyzed with the daily temperature and precipitation data of 50 observation stations in Liaoning Province between...Variation characteristics of drought strength,drought frequency,drought days and drought coverage were analyzed with the daily temperature and precipitation data of 50 observation stations in Liaoning Province between 1961 and 2008.The comprehensive meteorological drought index was considered as the standard of drought division.The results showed that spring drought,summer drought and autumn drought had enlarged coverage and increasing drought strength.The coverage and strength of spring drought had the most obvious variation.The days of spring drought mainly decreased,while the days of summer and autumn drought mainly increased.The frequency of spring drought was higher in western Liaoning,while that of the three types of drought was low in eastern Liaoning.展开更多
Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study c...Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions displayed different trends.展开更多
基金Supported by Science and Technology Development Fund of Liaoning Provincial Meteorological Bureau (200820)
文摘Variation characteristics of drought strength,drought frequency,drought days and drought coverage were analyzed with the daily temperature and precipitation data of 50 observation stations in Liaoning Province between 1961 and 2008.The comprehensive meteorological drought index was considered as the standard of drought division.The results showed that spring drought,summer drought and autumn drought had enlarged coverage and increasing drought strength.The coverage and strength of spring drought had the most obvious variation.The days of spring drought mainly decreased,while the days of summer and autumn drought mainly increased.The frequency of spring drought was higher in western Liaoning,while that of the three types of drought was low in eastern Liaoning.
基金The Project of the Ministry of Science and Technology,No.2001BA611B-01National Meteorological Center,ZK2002C-04
文摘Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions displayed different trends.
