近50a青海黄南州降水变化特征

Analysis on Precipitation in Huangnan Qinghai Province in Recent 50 Years

选取青海东南部黄南州4个气象观测站近50 a(1961-2010年)降水资料,运用气候诊断分析方法,对黄南年降水量变化特征进行研究。结果表明:研究区域内各地年平均降水量有较大差异,在空间分布上自南向北逐渐减少,变异系数自南向北呈增加趋势,各地年降水量皆呈正态分布;区域内年降水除泽库外都呈减少趋势,各地变化趋势并不显著;黄南四季降水各地变化不同,但冬季都呈增加趋势,南部增加显著。突变分析表明,河南年降水量在1985年发生了一次由多到少的突变,尖扎、同仁、泽库可能在20世纪90年代初存在突变;周期分析表明,4站年降水量都存在10 a的周期性变化规律,此外,尖扎、同仁、泽库、河南还存在2～4 a、准2 a、3～5 a、3～5 a的短周期变化。

In this paper, the variation of annual precipitation in Huangnan Prefecture was analyzed based on the precipitation data observed by 4 meteorological stations in the prefecture during the period from 1961 to 2010 by u-sing the method of climatological diagnosis. The results show that there was a big difference in mean annual precipi-tation among the meteorological stations, and the annual precipitation was gradually decreased from the south to the north. The coefficient of variation revealed that there was an increase trend of annual precipitation from the south to the north, and the annual precipitation at all the stations was in a normal distribution. Except at Zeku, there was a decreased trend of annual precipitation in Huangnan Prefecture during the period of 1961 - 2010, but this trend was not significant. The variation of seasonal precipitation was different from different meteorological stations, but winter precipitation was in an increase trend at all the stations, especially in the south. Analyzed results revealed that a sharp reduction of annual precipitation occurred in the Henan region in 1985, and it occurred possibly around the early 1990s at Jianzha, Tongren, and Zeku meteorological stations. The results also revealed that there was a 10-year periodic change of annual precipitation at these 4 meteorological stations, and 2-4-year, 2-year, 3-5-year and 3 -5-year one at Jianzha, Tongren, Zeku, and Henan meteorological stations respectively.