盛夏高原季风指数的探讨及其对四川盆地降水的影响  

Discussion of Plateau Monsoon Index and Its Impact on Precipitation in Sichuan Basin in Midsummer

作　　者：庞轶舒 马振峰[1,2] 杨淑群[1,2] 杨小波[2,3] 

机构地区：[1]四川省气候中心,成都610072 [2]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072 [3]四川省农业气象中心.成都610072

出　　处：《高原气象》2017年第4期886-899,共14页Plateau Meteorology

基　　金：国家自然科学基金项目(41275097,40375031,41290255);四川省气象局科学技术研究开发课题(川气课题2015-青年-08,川气课题2015-开发-29)

摘　　要：综合考虑盛夏时期高原环流场与高度场的变化特征,提出了新的高原季风指数。通过相关统计、小波分析等统计方法,与其他高原季风指数进行对比研究,结果表明该指数能较好响应盛夏高原热力的年际变化,反映高原盛夏风场分布特征。在此基础上,利用该指数研究分析盛夏时期高原季风对四川盆地降水的影响。分析结果表明,盛夏高原季风偏强时,对流层中层印度半岛-孟加拉湾地区高度场偏高,西太平洋副热带高压,乌拉尔山阻塞高压,东北亚阻塞高压异常偏强,东亚/太平洋(EAP型)遥相关波列呈"+-+"分布。低层印度半岛-孟加拉湾和西太平洋高压外围的异常反气旋环流,将来自阿拉伯海、孟加拉湾和南海的暖湿气流输送至我国南方地区;乌拉尔山阻塞高压与东北亚阻塞高压之间的异常偏北气流和我国东北地区的异常东北风使北方冷空气南下。冷暖气流汇集于四川盆地,水汽辐合上升运动增强,导致该地降水偏多。A newQinghai-Tibetan plateau monsoon index was built on the basis of synthetically consideration of the wind and height field variation on Qinghai-Tibetan plateau. After comparing with other indices by statistical methods such as correlation coefficient and wavelet analysis,the newindex showed good response to the heat inter-annual variation of Qinghai-Tibetan plateau,and reflected the midsummer height and wind field of Tibetan plateau in a better way. On this base,the relationship between Qinghai-Tibetan plateau monsoon and precipitation of Sichuan Basin in midsummer was analyzed. The results showed that in midsummer,the strengthening of the plateau monsoon led the height over the Bay of Bengal-India strengthened,West Pacific Subtropical High,Ural Blocking High and Northeast Asia Blocking High abnormally enhanced,and the East Asia/Pacific（ EAP） teleconnection pattern being ＂＋-＋＂. In the lower troposphere,warm water air was transported from the Arabia sea,the bay of Bengal and the South China Sea to South China by anticyclones circulation around the IndianBengal high and West Pacific Subtropical High. On the other side,Northerly airflowbetween Ural Blocking High and Northeast Asia Blocking High,and northeast airflowover Northeast China brought cold air southward. The warm and cold air met in Sichuan Basin,the convergence and uplifting motion of water vapor led the increasing of local precipitation.

关 键 词：高原季风指数 对比分析 四川盆地盛夏降水 

分 类 号：P461[天文地球—大气科学及气象学]