黑河流域过去40a来降水时空分布特征

对４０ａ来黑河流域降水的时空变化特征进行了分析，在空间上，降水由西北向东南呈现出明显的增加趋势，但平原区和山区，东部和西部之间存在着差异，在纬向上约以９９．５°Ｅ经线为界，降水在水汽补给上存在一定差异，导致流域东，西部降水年内分配具有不同特点，在经向上降水由北向南递增，在东，西部地区，降水随高度的变化有所不同，西部呈线性增加，而东部多为非线性增加，且在海拔２４００～３０００ｍ之间出现最大降水高度带

Temporal and Spatial Precipitation Distribution in the HeiheCatchment, Northwest China, During the Past 40 a

The paper summaries temporal andspatial distributive characteristics of precipitation forthe Past 40 a at the Heihe catchment. Spatially, precipitation tends to increase obviously from northwest tosoutheast. However, the tendency appears to have difference between the alpine and plain areas and between the east and west. Vapor source is also differentbetween the east and west, which may be divided at99.5 E, so that distribution of monthly precipitationappears to be different in the eastern and the westernareas of the catchment. Longitudinally, precipitationincreases from north to south. Change of precipitation with altitude is different in the west and east ofthe catchment, precipitation appears to increaselinearly in the west and non-linearly in the east,which leads maximum precipitation at 2400~3000m. Based on distribution of precipitation, the paperdiscusses difference and connection of precipitationfor various seasons in alpine and plain, and easternand western areas. Change of precipitation series forthe various areas is also analyzed. In the past 40 a,change of precipitation tends to be similar in alpineand plain areas, and eastern and western areas of thecatchment it shows to have two different stages ofchange that is divided at the beginning of 1980. Precipitation tends to decrease markedly since 1980.