2008年初中国南方低温雨雪冰冻天气的季节内振荡特征  

Intraseasonal Oscillation Characteristics of Extreme Cold,Snowy and Freezing Rainy Weather in Southern China in Early 2008

作　　者：马宁[1] 李跃凤[2] 琚建华[3] 

机构地区：[1]中国气象科学研究院,北京100081 [2]国家气候中心,北京100081 [3]云南省气象局,云南昆明650034

出　　处：《高原气象》2011年第2期318-327,共10页Plateau Meteorology

基　　金：国家重点基础研究发展规划项目(2006CB403603);国家自然科学基金项目(40675056);国家科技支撑计划项目(2007BAC29B02;2007BAC03A01)共同资助

摘　　要：利用中国气象局国家气象中心750站逐日平均气温和降水资料、NCEP/NCAR再分析的逐日风场和近地面气温资料、以及NOAA逐日向外长波辐射资料,分析了2008年1月我国南方发生的低温冰冻雨雪天气异常。结果表明,这次冰雪灾害伴有异常的季节内振荡特征,整个过程共包括4次降温、降水过程,这4次降温过程都在近地面气温30~60天振荡的负位相控制下,而10~20天振荡的同位相叠加使第一、三次过程的降温更加明显。冰雪灾害前期（第一、二次过程）我国南方主要受由北向南传播的两种尺度（30~60天、10~20天）近地面气温季节内振荡的共同影响,以剧烈的降温天气为主;后期（第三、四次过程）主要受近地面气温和风场30~60天振荡的影响导致持续低温,同时伴有明显的降水,造成了严重的雨雪冰冻灾害。此外,热带季节内振荡（MJO）的活动对这次低温冰冻雨雪也有一定的影响,冰雪灾害前期赤道东印度洋到孟加拉湾一带MJO对流活动受抑制,西南风和水汽输送不足,没有为我国南方带来明显的降水;后期赤道东印度洋MJO对流异常活跃,对流层低层有暖湿空气流入我国南方,配合近地面冷空气的持续影响产生大范围的低温冰冻雨雪灾害。Using the daily mean temperature and precipitation data at 750 stations of National climate center,daily wind field and the temperature near the surface and daily outer long-wave radiation of NOAA,extreme cold,snowy and freezing rain weather occurred in Southern China in January 2008 is analyzed.The result shows that there is exceptional intraseasonal characteristic in this disaster.Four processes with temperature drop and precipitation of the disaster weather occurred against a background of negative 30~60 d oscillations of temperature near the surface,and the negative phase of 10~20 d oscillations reinforce the first and third temperature drop processes.The prior period had a principle weather with severe cold air with the influence of southward moving 30~60 d and 10~20 d oscillations of temperature near the surface,and 30~60 d low frequency temperature coincident with 30~60 d low frequency convergent circulation caused severe cold,snow weather,and freezing rainy weather in the later period.Further analysis about the influence of MJO indicates that the inactive MJO convection over eastern tropical Indian Ocean and Bay of Bengal caused weaker southwest wind and fewer vapor and so not very much precipitation in Southern China during the prior period of the severe weather disaster.While the later period,the active MJO convection over eastern tropical Indian Ocean and Bay of Bengal brought Southern China plenty warm and moist air and caused severe snowy and freezing rainy weather.

关 键 词：低温冰冻雨雪天气 季节内振荡 MJO 

分 类 号：P426.63[天文地球—大气科学及气象学]