Spatial-temporal characteristics of precipitation in the Lake Dongting Basin from 1960 to 2008
Based on the monthly data of 27 meteorological stations from 1960 to 2008 and with the synthetic usage of climatic statistics methods and GIS spatial analysis techniques,the spatial-temporal characteristics of precipitation changes in the Lake Dongting basin are analyzed.The results show that：（1） during the period of 1960-2008,the basin＇s annual precipitation takes on a slight increasing trend,while its seasonal precipitation during the same period presents a decline trend in the spring and autumn and an increasing trend in the summer and winter,especially with the most sigrificant increasing trend in the summer. But in the recent 10 years of 1999-2008,the basin＇s annual precipitation oppositely has a remarkable decreasing tendency.The seasonal orecipitations have an increasing trend in winter and a decreasing tendency in the other three seasons.（2） in the last 10 years of 1999-2008,over the Lake Dongting basin, except one meteorological station whose annual precipitation still has an increasing tendency,at other sites,the annual precipitations decreases to a certain degree.Meantime,the distribution of precipitation in each month has become more imbalanced.In summer and winter,the precipitations have been respectively 2.85%and 3.07%more than the average over previous years,whereas in spring and autumn,they have been 1.35%and 11.43%less than the normal.Among them,the decline in September and October are more significant,but at the same time,the variation coefficients of precipitation also have an obvious increasing. As a consequence,these changes will lead to some adverse effects,such as a substantial reduction of the amount of water that flows in the probability tha regional drought occurs.
万方数据
维普
