西北区东部夏季极端降水事件同太平洋SSTA的遥相关

利用近50年月平均NCEP再分析高度场、风场、NOAA重构海表温度以及中国西北区东部38个台站逐日降水资料,运用SVD及合成分析等方法,研究了太平洋SSTA对我国西北区东部夏季极端降水事件的可能影响。结果表明,冬季太平洋海表温度对后期西北区东部夏季极端降水事件的影响最显著,并且赤道中东太平洋是影响西北区东部夏季极端降水事件的关键区,当赤道中东太平洋海表温度发生异常时,首先引起纬向和经向垂直环流圈发生异常,进而强迫大气环流发生调整,先后通过PNA和WP遥相关使得西太平洋副热带高压发生异常,最终使得西北区东部夏季极端降水事件发生异常。

Teleconnection between Summer Extreme Precipitation Event of East Part of Northwest China and Pacific SSTA

Using the height field,wind field of monthly mean NCEP reanalysis NOAA reconstruct sea surface temperature,daily precipitation data of 38 stations in east part of Northwest China in recent 50 years,and with SVD,composite analysis methods, the Pacific SSTA effect on extreme precipitation event of east part of Northwest China are researched.The result show that there are remarkable relations between winter Pacific SSTA and anaphase summer extreme precipitation event of east part of Northwest China,and equator middle-east Pacific Ocean is key area which affect to summer extreme precipitation event of east of Northwest China,when the winter SST occurs anomaly phenomenon in the equator middle-east Pacific Ocean,at first longitudinal and latitudinal departure circulation cells occur anomaly,then general circulation occurs adjustment,successively west Pacific subtropic high pressure also arise anomaly by PNA and WP from winter to summer,finally summer extreme precipitation event of east part of Northwest China occur anomaly phenomenon.