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

作　　者：陈豫英[1,2] 冯建民[1] 陈楠[1,2] 郑广芬[1] 穆建华[1] 辛尧胜 聂金鑫 杨建玲[1] 

机构地区：[1]宁夏气象防灾减灾重点实验室,宁夏银川750002 [2]宁夏气象台,宁夏银川750002

出　　处：《干旱区地理》2012年第1期56-66,共11页Arid Land Geography

基　　金：国家自然科学基金项目(40965008;41075053和41065005);宁夏科技攻关项目(KGX-12-09-02)共同资助

摘　　要：利用西北地区东部91站1961-2009年间的实测气温降水资料,分别计算了该区水分资源各分量降水、蒸发及可利用降水,使用REOF等统计方法,整体分析了该区可利用降水的时空变化特征。结果表明:西北地区东部水分资源匮乏且年际变化大,水分资源各分量时空分布极不均匀;总体上各分量从该区东南部向西北部递减,呈南多北少特征,其中该区东南侧的陕南、陇南、六盘山区及青藏高原东部部分地区年降水量、蒸发量和可利用降水量分别在500、200和200 mm以上,年降水可利用率在30%～50%,可利用降水标准差达80～110 mm,而该区西部的河西走廊和青海西部的年降水量不足50 mm、年可利用降水量不到10 mm,年降水可利用率不足10%,可利用降水标准差在20 mm以下;各分量夏季最大,冬季最小,5～9月是该区主要降水和可利用降水的集中期;降水在水资源各分量中起决定性作用,因此降水的小幅变化导致可利用降水的大幅变化是降水稀少的西北地区东部可利用降水资源匮乏的主要原因,但气温变化造成的影响也不可忽视;西北地区东部5～9月可利用降水异常分布的局域特征明显,常出现陇南、河东、高原、河西走廊等4种异常分布特征。近50 a来,区内可利用降水总体呈东部减少(六盘山区及陇南区尤甚),西部增加的变化格局。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 d

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 

分 类 号：P426.614[天文地球—大气科学及气象学]