西北地区极端降水事件及环流特征分析  

Characteristics of Extreme Precipitation Events and Their Circulations in Northwest China

作　　者：张乃升 戴宇珩 

机构地区：[1]民航西北空中交通管理局气象中心,陕西西安710082 [2]民航甘肃空管分局气象台,甘肃兰州730087

出　　处：《安徽农业科学》2012年第30期14876-14878,14939,共4页Journal of Anhui Agricultural Sciences

摘　　要：选取我国西北地区99个气象站1959～2008年的逐日降水资料,定义了不同台站的极端降水阈值,据此分析了极端降雨日数时空分布特征,并分析了极端降水日数偏多年、偏少年的环流特征。结果表明,空间上,西北地区极端降水阈值、极端降水日数和极端降雨量均是自北向南逐渐增大;时间上,极端降水日数和极端降雨量除西北东南部呈减少趋势,其他地区均表现为增加趋势,且存在明显的年际变化特征;在西北地区极端降水日数偏多年和偏少年,其环流特征存在明显的差异。Based on the daily precipitation data collected from 99 observational stations in Northwest China during 1959-2008,the threshold value of extreme precipitation,the frequency of extreme precipitation days and their circulations were analyzed.The results indicated that the threshold values of extreme precipitation event thresholds were gradually increasing from north to south in Northwest China.The extreme precipitation days and extreme rainfall decreased in the northeast of Northwest China,but the other showed increasing trend in Northwest China.Inter-annual variations of the frequency were remarkable.The circulations had obvious differences in more extreme precipitation days frequency years and fewer years.

关 键 词：西北地区 极端降水 环流特征 

分 类 号：S161.6[农业科学—农业气象学]