祁连山区空中水资源研究

Research on Vapor and Precipitation Resources over the Qilian Mountain Area

利用祁连山地区8个气象观测站1960-2002年逐日气象观测资料和1970-1997年NCEP/NCAR再分析资料(2.5°×2.5°格距),分析了祁连山地区的空中水资源状况。结果表明:该区大气水汽含量从春季到夏季逐渐升高,之后又逐渐减少,对应全年降水主要集中在5-9月,占年降水量的86.8%;从1987年西北地区气候转型前后2个时期的比较来看,1987年后比1987年之前平均年降水量增加了22.7 mm(约8.1%),而且主要是春、夏季降水增加了,这将有益于该地区生态环境的改善。从空间分布来看,祁连山地区中部的年降水量大,东部和西部降水较少,其中西部最少。祁连山地区平均每年水汽输入量约为885.4亿m3,水汽输入主要在600 hPa以下层,高层全年多数时间整体表现为辐散,且水汽主要来源于经向输送。

The cloud -water resources of the Qilian Mountain were analyzed by using the observed data of eight meteorological stations from 1960 to 2002 and the NCEP/NCAR data （2.5° ×2.5°） for the period of 1970 - 1997. Results show that the water vapor amount gradually increased from spring to summer, and then decreased; the precipitation there was concentrated in May to September which was in the proportion of 86.8% to annual precipitation. Comparing the preceding period （ 1970 - 1986） with the succeeding period （1988 -1997） of climatic change in Northwest China, the annual mean precipitation there increased more than 8.1% in the succeeding period （ mainly in spring and summer）, which was beneficial to the ecological improvement there. The precipitation in the middle part of the Qilian Mountain was much more than that in eastern and western part. The annual water vapor input was 885.4 × 10^8 m^3, which mostly came from the levels under 600 hPa, and it divergenced over 600 hPa at most time of a year. The water vapor mainly came from longitudinal input.