河南夏季干旱气候特征分析

Characteristic Analysis of Summer Drought in Henan Province

利用1961-2010年河南省103站降水量数据,并结合综合气象干旱指数(CI),分析河南省夏季干旱的时空分布特征,及副高、厄尔尼诺和拉尼娜与河南夏季干旱的关系。研究表明:1)初夏和盛夏降水量都有上升趋势,上升率分别为6.065 mm/10a和7.505 mm/10a,初夏旱和初夏重旱出现的概率分别为44%和22%,伏旱和伏旱重旱出现的概率分别为20%和0。2)1961-2010年,河南6个分区初夏降水量都呈增加趋势,初夏干旱日数6个区域都呈减少趋势;盛夏降水量除豫北呈减少趋势外,其他5个区域都呈增加趋势,干旱日数6个区域都呈减少趋势。3)河南初夏旱年和伏旱年高纬度冷空气活动少且不易到达河南,副高偏弱。4)7月副高异常偏西时,河南盛夏一般降水偏多;从降水距平百分率上来看,拉尼娜次年初夏干旱的几率较大。

Based on the precipitation data of 103 dex, temporal-spatial features of the summer drought drought and western Pacific subtropical high, E1 Nino, meteorological stations of 1961-2010 and CI inwas analyzed, the relationships between summer La Nina also were studied. The results are as fol-lows. 1 ） The precipitation of early summer and midsummer showed a slowly increasing trend with the rate of 6. 065 mm/10a and 7. 505 mm/10a; the probability of early summer drought and heavy early summer drought is 44% and 22% , and that of midsummer drought and heavy midsummer drought is 20% and 0. 2） The precipitation of six sub-regions of early summer showed an increasing trend, and drought days of early summer showed a decreasing trend. The precipitation of midsummer is not spatially uniform, and it exhibited decreasing trends in north, but increasing trends in the rest sub-regions of the province. Whiledrought days of midsummer showed a decreasing trend in 1961-2010. 3） The cold air is less frequently and difficult to arrive in Henan province, meanwhile western Pacific subtropical high is weaker in early summer drought and midsummer drought years. 4） The rainfall of midsummer is more than normal when western drought Pacific subtropical high is further west to its normal position, and the probability of early summer is high in La Nina next years.