我国西北地区东部可降水量变化趋势的初步研究

A Preliminary Study on the Evolutionary Trend of Precipitable Water in the East of Northwest China

用1951年1月—2000年12月NCEP/NCAR再分析比湿资料,分析了西北地区东部天水市上空对流层整层可降水量的演变特点,并与全球同纬度带的情况作了对比。结果指出:近50a来,西北地区东部对流层可降水量处于明显的下降阶段,其下降幅度在全球同纬度带中最大,是20世纪90年代中后期天水重大干旱事件发生的一个背景条件。

By utilizing of the NCEP/NCAR reanalysis grided humidity data during January 1951 to November 2000,the evolutionary feature of the whole tropospheric precipitable water over Tianshui in the east of Northwest China,is analyzed and contrasted with those in other places at the same latitude over the world.Results show that in the past 50 years,precipitable water in the troposphere over the east of Northwest China was in a desending,and its descending amplitude is the largest among those at the same latitude.This reveals a background condition for the severe droughts at Tianshui in the mid-late 1990’s.