摘要
文章从2009/2010年初夏(5/6月)环流指数特征、月平均环流场特征、500hpa环流场以及气象要素变化特征等方面分析了初夏干旱的基本成因。结果表明,造成初夏干旱的主要原因有:青藏高原属高压控制型,即西太平洋热带高压强度偏强,其位置明显偏西,控制高原,高原上盛行偏西气流或偏北气流;高压控制的印度西北部抑制了水汽输送;伊朗高压呈东北西南向,此时西太平洋副热带高压脊线在25毅N左右,位置偏南或强度偏弱。
The obvious dry early summers have been appeared in year 2009 and 2010 in the Lhasa area with postponed rainy season and that seriously impacted on the agricultural production in the agricultural areas of Lhasa.In the present paper,the causes and impact of dry early summer appeared in year 2009 and 2010 in Lhasa were analyzed with the characteristics of atmospheric circulation and meteorological factors of the year 2009 and 2010 so that as an indicator for forecast in the future.
关键词
西藏拉萨
初夏干旱
气温偏高
降水偏少
环流特征
Lhasa
Dry early summer
Higher temperature
Less precipitation
Circulation patterns
