摘要
利用云南122个测站1961-2009年秋季(9～11月)、冬季(12月～次年2月)降水量和同期NCEP/NCAR月平均再分析资料,计算了整层大气可降水量和水汽通量,并对云南区域秋、冬季的水汽输送特征进行了分析,揭示出秋、冬季异常降水与可降水量、水汽通量的关系。结果表明,秋、冬季云南可降水量从滇西北向南增加,呈"U"形分布,秋季可降水量为10～32.5kg.m-2,冬季为5～20kg.m-2。秋、冬季云南降水的多(少)与其上空的水汽含量多(少)有关。云南秋季降水的水汽来自印度洋、孟加拉湾(下称孟湾)、南海及西太平洋。冬季主要是中纬度的西风水汽输送。秋季降水和整层水汽通量具有"气旋式-反气旋式"相关矢量场分布。秋季旱涝主要与孟湾、中南半岛至云南的南风水汽通量输送异常有关,还与低纬度西风强弱及位置有关。当对流层中低层孟湾附近的季风低压较强时,孟湾、中南半岛及云南的南风水汽通量亦较强,云南秋季易出现洪涝,反之则出现干旱。冬季降水异常与中南半岛的整层水汽通量相关矢量有关。2009年秋季云南降水特少的主要原因是由于对流层中低层高原南部、孟湾、中南半岛及云南受强反气旋环流控制,云南为经向异常负距平水汽通量,没有充足的水汽输送,使云南上空大气含水量较常年同期异常偏少。
Using the monthly precipitation at 122 stations in Yunnnan from 1961 to 2009 and the monthly reanalysis data of NCEP/NCAR,the air column precipitalbe water（PW） and water vapor flux in autumn and winter are calculated.Based on those data,the features of water vapor transportation are studied.The relationships of Yunnan precipitation and PW and water vapor transportation are also studied.The results show that the air column PW over Yunnan has a feature of southeast-northwestern ＇U＇ pattern.The air column PW over Yunnan is changed from 10 to 32.5 kg·m-2 in autumn but from 5 to 20 kg·m-2 in winter.The precipitation in Yunnan is correlated to the air column PW in autumn and winter.The resource of Yunnan autumn precipitation are from the Indian Ocean,the Bay of Bengal and the South China Sea.The resource of Yunnan winter precipitation is from westerly wind water vapor transportation in middle latitude.The correlation vector distribution of Yunnan autumn precipitation and water vapor transportation is the type of cyclonic-anticyclone.The autumn precipitation is related to the southerly water vapor transportation in the Bay of Bengal and the Indochina Peninsula and to the intensity and location of the westerly wind of low latitude too.The stronger the monsoon depression in middle and upper troposphere over the Bay of Bengal is,the more southerly water vapor transportation from the Bay of Bengal and the Indochina Peninsula to Yunnan are,the more the autumn precipitation in Yunnan is too.The winter precipitation is correlation of the water vapor transportation from the Indochina Peninsula to Yunnan.The less of the air column PW and the less of the meridional water vapor transportation and stronger of the anti-cyclone in middle and upper troposphere over the Bay of Bengal and the Indochina Peninsula are the reasons that precipitation in Yunnan during the autumn and winter of 2009 is less comparing with the climatologically normals.
出处
《高原气象》
CSCD
北大核心
2011年第6期1534-1542,共9页
Plateau Meteorology
基金
国家自然科学基金项目"水汽输送异常对低纬高原地区旱涝灾害的影响研究"(40965006)
国家自然科学基金重点项目(U1133603)
云南省自然基金项目(2007D145M)
干旱气象科学研究基金项目(IAM201012)共同资助
关键词
云南地区
大气可降水量
秋、冬季降水
水汽输送
Yunnan Province
Air column precipitable water
Autumn and winter precipitation
Water vapor transportation
