摘要
2009年秋季至2010年初夏,云南遭受了有资料记录以来最严重的干旱,其中2009年秋季是有资料记录以来降水偏少最明显的年份,全省平均降水比历年同期偏少50%以上。通过诊断方法分析了云南秋季降水和大气环流异常的特征,结果表明在多年平均情况下,云南秋季大部分地区的降水占年降水总量的20%以上,对年降水量的变化有重要影响;2009年秋季云南区域大气低层的水汽持续偏少、高层辐合低层辐散的高低层流场配置是这次干旱产生的最直接原因;另外,持续偏西偏强的西太平洋副热带高压、弱冷空气和弱暖湿气流活动,以及北方冷空气与南方暖湿气流影响云南的不同步、夏季风环流的提前结束等都对这次干旱过程产生了重要的影响。
From autumn 2009 to early summer 2010,Yunnan has suffered a most serious drought disaster.In this drought process,autumn rainfall is the least since the data record and its anomalous precipitation percentage exceeds-50%.Based on diagnostic analysis,the anomalous characteristics of autumn rainfall and atmospheric circulation are investigated.Results show that the autumn rainfall accounts for more than 20% of annual rainfall.The continuously less water vapor from low to high levels,the convergence at lower level companied with divergence at higher level over Yunnan region directly result in the drought.Otherwise,the continuously strong subtropical high over the western Pacific,the weak cold air and the weak warm and wet flow as well as their out-phase effects,the early retreat of summer monsoon circulation also play significant role on this drought.
出处
《大气科学学报》
CSCD
北大核心
2012年第2期229-239,共11页
Transactions of Atmospheric Sciences
基金
国家基金委-云南省人民政府联合基金项目(U0833602)
国家自然科学基金资助项目(41065004)
云南省气象局业务能力建设专项"2009/2010年云南干旱分析"
关键词
云南干旱
大气水汽含量
西太平洋副热带高压
南支槽
drought in Yunnan
atmospheric vapour
the western Pacific subtropical high
westerly trough in BOB
