1971-2010年青海高原不同功能区可降水量的变化特征

利用1971-2010年青海省境内43个气象站的降水量和水汽压月资料, 运用整层大气可降水量经验公式, 计算了青海高原东部农业区、环青海湖区、三江源区和柴达木盆地4个不同生态功能区的可降水量和降水转化率. 结果表明: 不同生态功能区可降水量均呈单峰形态分布, 均在夏季达到最大值; 降水转化率在三江源区和东部农业区呈双峰分布, 柴达木盆地和环青海湖地区呈单峰分布. 不同生态功能区年可降水量近40 a均呈上升趋势, 其中, 柴达木盆地和环青海湖区上升趋势显著; 不同生态功能区年可降水量均发生了突变, 东部农业区发生在1983年, 柴达木盆地发生在1996年, 三江源区和环青海湖区发生在1993年. 可降水量自西向东呈逐渐增加趋势, 降水转化率形成以青海湖区为中心的马鞍形场.

The variation of precipitable water in different ecological function regions of Qinghai Plateau from 1971 to 2010

Based on the data of monthly mean precipitation and water vapor pressure from 43 weather stations in Qinghai Province from 1971 to 2010, the precipitable water (PW) and precipitation conversion efficiency are calculated by using an empirical formula of atmospheric total PW for the four ecological function regions, i.e., the eastern agricultural area, area of Three Rivers Sources, the area around Qinghai Lake and Qaidam Basin. The results show that the precipitable water of all ecological function regions presented a unimodal distribution form, with the maximum in the summer. The precipitation conversion efficiency over the area of Three Rivers Sources and the eastern agricultural area presented a bimodal distribution, but a unimodal distribution over Qaidam Basin and the area around Qinghai Lake. The precipitable water of all ecological function regions had increased during the 40 years, especially in Qaidam Basin and the area around Qinghai Lake. There were abrupt changes of PW in all ecological function regions; in the eastern agricultural area and Qaidam Basin abrupt change happened in 1983 and 1996, respectively; in the area of Three Rivers Sources and the area around Qinghai Lake abrupt change occurred in 1993. The PW had increased gradually from west to east, and the precipitation conversion efficiency had decreased towards Qinghai Lake.