南水北调西线一期工程引水区和黄河上游区域气候特征分析

Analyses of the Climatic Characteristics in the Water Diversion Areas of the Western Route Project of South-North Water Diversion and the Upstream Areas of Yellow River

利用引水区和黄河上游地区25个站1951-2000年50a的气温和降水逐日资料，分析了研究区域降水的时空分布特征；把引水区和黄河上游地区分成7个小区，利用小波分析的方法研究了各小区气温和降水的多时间尺度特征．结果表明：黄河上游和南水北调西线引水区夏、秋、冬三季降水以同步的变化为主，其次为黄河上游与引水区之间存在反位相的变化．春季降水主要表现为黄河上游与引水区之间存在反位相的变化，其次才表现为一致的变化．各区的气温均以同步升温为主．降水具准3a和准22a周期，气温的振荡周期主要是2～5a的小周期和准11a的周期．引水区和黄河上游地区近50a来夏季的降水在一致变化的基础上也有着明显的区别．

Using the daily data of temperature and precipitation from 25 stations in the water diversion areas and the upstream areas of Yellow River from 1951 to 2000, the temporal and spatial characteristics of precipitation in these areas are analyzed with the EOF method. The water diversion areas and the upstream areas of Yellow River are partitioned into 7 regions using the methods of statistic test clustering analysis and REOF. The multi --temporal scale characteristics of temperature and precipitation in each region are researched through wavelet analysis. The results indicate that the annual precipitation in the water diversion areas is more than that in the upstream areas of Yellow River. The variations of precipitation in summer, autumn and winter in these two areas are consistent primarily, with a secondary variation of inverse phase. The variations of precipitation in spring in these two areas are primarily opposite, with a secondary variation of same phase. In addition, there is an opposite variation of annual precipitation in the northwest--southeast direction. The variation of temperature in each region is increasing primarily. An analysis, which passes the significant test with the confidence of 95 %, shows that the period of precipitation is quasi-3 years and the oscillatory period of temperature is mainly 2 - 5 years and quasi-11 years. The precipitation variations in summer during these 50 years in the water diversion areas and in the upstream areas of Yellow River are basically the same, but sometimes they are obviously different.