九寨沟、黄龙地区水资源的变化特征及成因分析

Water Resource Variations in Jiuzhaigou-Huanglong and Cause Analysis for Its Change

利用九寨沟、黄龙地区附近代表站的降水资料及NCEP／NCAR1959年-2004年共46年月平均再分析资料，采用小波分析、合成分析等方法对九寨沟、黄龙地区水资源的气候特征进行了研究。结果发现，九寨沟、黄龙地区的降水以及水资源的多年平均值分别为691mm、247mm，季节变化明显。46年来，该区年平均降水以及水资源的总趋势是减少的，20世纪80年代尤其是1994年以来减少趋势尤为显著；两者的减少主要发生在7月份。本区年水资源的年代际变化最显著，主要是15年左右的周期。九寨沟、黄龙地区7月份降水、水资源的变化与大气环流和南来水汽的变化有密切关系，主要的影响因子是巴尔喀什湖以东到贝加尔湖以南地区的500hPa高度场形势和来自南海西太平洋地区的偏南风水汽输送。高度场以及南来水汽两个主要因子的变化导致80年代尤其是1994年以来九寨沟、黄龙地区7月份降水显著减少，进而影响到全年降水，使其也呈减少趋势；降水的异常变化进一步引起了九寨沟、黄龙地区水资源的异常变化。

Water resource is of fundamental importance to human welfare, ecosystem and economic activities. In Jiuzhaigou-Huanglong region, water is the most important tourism resource. But in recent years, water resources in the region are decreasing with the increased tourism activities and water quality is deteriorating. The government departments have paid a great attention to this situation and invested a great sum of funds in it. By using the wavelet and composed analysis methods, features of water resource in Jiuzhaigou-Huanglong are studied on the base of NCEP/NCAR monthly reanalysis data and rainfall observation representative stations of Jiuzhaigou-Huanglong from 1959 to 2004. It is found that, the annual total precipitation and water resource of the region are 691 ram and 247 mm, and mostly distribute in summer with the value of 346mm,136mm. From 1959 to 2004, the precipitation and water resource in Jiuzhaigou-Huanglong had been decreased and the decrease trend is the most obvious in July from 1980＇ s, especially between 1994 and 2004. The Variations of the precipitation and water resouce of Jiuzhaigou- Huanglong in July have a close relation with the 500hPa geopotential height between East to Balkhash Lake and South to Baikal, and also closely related to the activity of the monthly water vapor from South China Sea and the west Pacific Ocean with summer monsoon in July. From 1994 to 2004, the westward and northward march of the water vapor transport by summer moonsoon from South China Sea and the west Pacific Ocean had a obvious weakeness in July and led to the obvious decrease of the water vapor arriving in Jiuzhaigou-Huanglong; During this period, the 500hPa geopotential height between East to Balkhash Lake and South to Baikal had a obvious enhance and at last became a ridge of high pressure region between 1994 and 2004. The anomaly variations of the 500hPa geopotential height and southly water vapor in July in recent years, which are not conducive to the occurrence of the precipitation of Jiuzhaigou-Huanglong region, have a important influence on the decrease of precipitation in July of this region and further affect the variation of the precipitation in total year, and at last affect the change of the water resource of Jiuzhaigou-Huanglong region in these years.