摘要
利用陕西省1961-2009年78个气象观测站的逐日降水资料,分析该地区极端强降水事件的时空演变特征。结果表明:陕西省极端强降水阈值在18.7～39.5mm/d,由南向北呈阶梯状递减。极端强降水事件出现在5～9月,7～9月最集中。陕西省极端强降水事件以持续1d为主。持续2d的极端降水主要分布在陕南中南部,3d及以上的极端降水为偶然事件。49年来,陕西省年极端强降水事件的趋势变化不明显,但夏季呈增加趋势。EOF分解表明,极端强降水事件有2个主要的空间分布型,第1型(EOF1)为全区一致的偏多(少)型,相似年份有11年,此型存在准22年、准8年的周期变化;第2型(EOF2)为东南与西北相反变化型,相似年份有9年,此型存在12～14年以及2～3年的周期变化。
In this paper,the spatiotemporal change of annual extreme precipitation events is analyzed using the daily precipitation data observed by 78 meteorological stations in Shaanxi Province during the period 1961-2009. The results show that the threshold of extreme intensity precipitation varied in a range of 18.7-9.5 mm/d,and it decreased northward. The extreme precipitation events in the province occurred mainly in rainy season from May to September,especially during the period from July to September,their duration was mostly for one day,the extreme precipitation events with 2-day duration occurred mainly in the central-southern part of south Shaanxi Province,and those with 3-day duration were occasional. The change trend of annual extreme precipitation events in the province was not significant in recent 49 years,but the extreme precipitation events increased in summer. The EOF results reveal that there were 2 main spatial distribution patterns of frequency of extreme precipitation events in the province. The first one （EOF1） was that the high or low frequency of extreme precipitation events was accordant in whole province,and there were 22-year and quasi-8-year periodic changes. The second one （EOF2） was that the frequency of extreme precipitation events in the southeastern part was opposite to that in the northwestern part,and there were the 12-14-year and 2-3-year periodic changes.
出处
《干旱区研究》
CSCD
北大核心
2011年第1期151-157,共7页
Arid Zone Research
基金
国家自然科学基金项目(40575004)
关键词
降水量
时空分布
周期变化
陕西
precipitation
spatiotemporal distribution
periodic change
Shaanxi Province
