1961—2009年西北地区东部降水时空分布及成因  

Spatiotemporal Distribution and Formation Causes of Precipitation in the East of Northwest China during the Period of 1961- 2009

作　　者：朱晓炜[1] 杨建玲 崔洋[1] 谭志强 

机构地区：[1]宁夏气候中心,宁夏银川750002 [2]宁夏气象科学研究所,宁夏银川750002 [3]宁夏气象台,宁夏银川750002

出　　处：《干旱区研究》2013年第6期1094-1099,共6页Arid Zone Research

基　　金：国家自然科学基金项目(41065005);国家科技部公益性行业(气象)专项研究(GYHY201306027);宁夏自然科学基金(NZ12281)

摘　　要：利用西北地区东部99个站点的逐月降水资料,对降水的时空分布进行研究。西北地区东部降水呈变干趋势,秋季最明显,年降水没有发生明显的突变。近10 a,秋季的年代际降水有增加的趋势。西北地区东部降水主要集中在宁夏南部与青海东部。各个季节及年降水的周期性不一致,存在4 a、8 a和12 a左右的周期。用EOF(经验正交分解法)对年降水进行分析,第一模态全区域呈现一致性;第二模态呈现南北相异;第三模态东西相异明显。结合地面状况,发现地形是影响西北地区东部降水分布的重要因素之一,其中最明显的地形系统是高原,六盘山、沙漠戈壁(包括巴丹吉林沙漠、腾格里沙漠和毛乌素沙地)等地形对降水分布也有影响。The spatiotemporal distribution of precipitation was researched based on the monthly precipitation data form 99 meteorological stations in the east of northwest China. The results revealed that the precipitation in the study area was slightly decreased,especially in autumn,and there was no significant sharp change of annual precipitation. Precipitation in autumn was in an increase trend in recent decade. Precipitation in the east of northwest China occurred mainly in the southof Ningxia and the east of Qinghai. There were the 4-,8-and 12-year periodicities of precipitation. EOF was used to analyze the annual precipitation,the first mode was identical in all the regions,the second one was different between the north and the south,and the third one was different between the west and the east. Based on the ground conditions,it was found that the landforms,especially the plateaus,Liupanshan Mountain,deserts and Gobi deserts（ including the Badain Juran Desert,Tengger Desert and Mu Us Sand Land）,were the important factors affecting precipitation in the east of northwest China.

关 键 词：降水 时空分布 周期性 EOF(经验正交分解法) 地形 西北地区东部 

分 类 号：P468.024[天文地球—大气科学及气象学]