1960~2011年洞庭湖流域降水量变化特征

Characteristics of Precipitation Variations in the Dongting Lake Basin during 1961-2011

洞庭湖流域的降水变化将改变洞庭湖的水源补给,对洞庭湖湿地生态系统具有重要影响。以位于洞庭湖流域及附近的26个气象站的1960~2011年逐月的月降水量为基础数据,分析了降水量的年际及年内变化特征;采用Mann-Kendall非参数趋势检验法,分析了降水量的变化趋势;利用协同克吕金插值法,对26个气象站的降水量进行了空间插值,分析了降水量时空变化特征。结果表明,1960~2011年期间,洞庭湖流域的年降水量在减少,春季和秋季降水量在减少,但夏季和冬季降水量在增加,年降水量和季节降水量都没有显著变化趋势。洞庭湖流域西部、南部和东北部山区的年降水量多于中部和北部的平原地区,北部、东南部以及南部的局部的年降水量在增加,其它地区的年降水量多在减少;春季,除流域东南部降水量在增加外,其它地区的降水量都在减少,夏季,流域内大部分地区的降水量在增加,秋季,大部分地区的降水量在减少,冬季,流域内各气象站的降水量都在增加。

Variations in precipitation would change the water-supply in the Dongting Lake, which has significant impacts on the wetland ecosystems in the Dongting Lake Basin. Based on the data of monthly precipitation of 26 meteorological stations in the Dongting Lake Basin and surrounding area during 1960-2011, the temporal and spatial characteristics, and variation trends of precipitation were analyzed using the Co-Kriging interpolation approach and Mann-Kendall nonparametric methods. The results showed that average annual precipitation was 1 372.8 mm, the precipitations in spring, summer, autumn and winter were 468 mm, 505 mm, 243 mm and 157 mm in the Dongting Lake Basin during 1960-2011; the annual precipitation, and precipitations in spring and autumn has been decreasing, but the precipitations in summer and winter has been increasing during 1960-2011; the annual precipitation was abundant in the mountain regions in the western,southern and northeast parts and deficient in the plains in the central and northern parts of the Dongting Lake Basin.