干旱区地理2012，Vol.35Issue(1)：56-66,11.
西北地区东部可利用降水的时空变化特征
Spatio-temporal variation characteristic of the utilizable precipitation in eastern part of Northwest China
摘要
Abstract
Using the observed temperature and precipitation data of 91 observation stations located in eastern part of northwest China during 1961 to 2009, the precipitation, evaporation and utilizable precipitation were calculated, ap- plying the statistical methods such as EOF, REOF and so on, the spatiotemporal variation characteristic of utilizable precipitation in eastern part of northwest China was analyzed. The result shows as follows ： （ 1 ） The mean annual pre- cipitation in eastern part of northwest China was less than 350 mm, but the evaporation was up to 270 mm, only 13% of precipitation was utilized,moisture resource was scarce and its inter-annual variation was great in this re- gion. （2）The spatiotemporal distribution of moisture resource in this region was extremely asymmetric, moisture re- source reduced progressively from southeast part to northwest part as a whole. In south part of this region, utilizable precipitation was up to 30% to 50%, but over 90% precipitation was evaporated in north Ningxia, west Qinghai and most part of Shaanxi. In Gansu Corridor,99% precipitation was evaporated. Most moisture resource was in summer and least in winter. The precipitation, evaporation and utilizable precipitation during May to September was up to 82% ,79% and 91% repectively in whole year, so the period from May to September was not only the main precipi- tation period, but also the concentration period of utilizable precipitation. （3） Precipitation played a decisive role ineach component of moisture resource,little variation of precipitation could lead to big variation of utilizable precipi- tation, so it was the main reason that caused the dificient of utilizable precipitation resouce in the eastern part of northwest China. But the influences caused by temperature variation couldn＇t be ignored. （4） The distribution of uti- lizable precipitation during May to September in eastern part of north - west China was abnormal with obvious re- gional distribution characteristic, by the EROF analysis during May to September in this region, the cumulative vari- ance contribution rate of first 4 rotation load vectors was up to 53%, so there were usually 4 abnormal distribution modes, they are Longnan, Hedong, Plateau and Gansu Corridor distribution modes. （ 5 ） In recent 50 years, the utiliz- able precipitation reduced linearly in eastern part of northwest China and increased in western part, but the decrea- sing rate was bigger comparing with the increasing rate, it was in accord with the variation of precipitation in this re- gion.关键词
西北地区东部/5-9月可利用降水/REOF分析/空间分布模态及时间系数Key words
eastern part of northwest China/utilizable precipitation during May to September/REOF analysis/spatial distribution mode and temporal ratio分类
天文与地球科学引用本文复制引用
陈豫英,冯建氏,陈楠,郑广芬,穆建华,辛尧胜,聂金鑫,杨建玲..西北地区东部可利用降水的时空变化特征[J].干旱区地理,2012,35(1):56-66,11.基金项目
国家自然科学基金(40901061)资助 （40901061）
