2008年初中国南方雪灾大尺度环流背景分析  

The large scale circulation of the snow disaster in south China in the beginning of 2008.

作　　者：王亚非[1] 李琰[1,2] 李萍云[1] 刘英[1] 

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京 100081 [2]南京信息工程大学,南京 210044

出　　处：《气象学报》2008年第5期826-835,共10页Acta Meteorologica Sinica

基　　金：国家自然基金委项目(40675034);JICA中日政府间合作项目;中国气象科学研究院灾害性天气重点实验室2008自主研究项目

摘　　要：分析2008年1月到2月初发生在中国南方雪灾冻雨的大尺度环流场,结果表明:这次南方强雨雪天气过程是北方冷空气和南方暖空气在中国南方地区持续维持、高低纬系统相互作用的一个典型个例。AO指数在1月中旬由负变正,表明了半球尺度环流的大幅度调整,高纬度80°E附近地区阻高形势的维持是1月中下旬到2月初阴雨雪天气过程持续的清晰指标;阻塞高压所伴随的能量频散使得准定常波持续从中高纬地区传播到较低纬度的长江及其以南地区,使得当地的气旋性环流得以维持;在乌拉尔山到贝加尔湖的强大阻塞高压的控制下,冷空气不能大举南下、只是不断的渗透到南方,与此同时受拉尼娜影响西太平洋暖池的海温不断增高,暖湿空气势力也是持续增强,代表暖势力暖池海温达到历史最强,冷空气在南方受阻形成静止态势。一旦阻塞高压在1月30日前后崩溃,供给江南地区气旋性环流的能源被切断,所以2月1日的降水过程以后江南地区的持续性降水也就随之结束。This study analyzed the heaviest snowfalls and icy rainfalls occurring in southern China from January to the beginning of February 2008. The results are summarized as follows： the disaster was associated with a persistent front of warm/cold air mass in southern China. It was result of the interaction between the weather systems in high latitudes and low latitudes. In mid-January 2008, the AO index changed from negative to positive, indicative of an adjustment of hemispheric circulation. The long lasting precip- itation well coincided with a blocking situation nearby 80~E during mid-January to early February. A diagnostic analysis indicates that the energy dispersion accompanying the blocking high compelled stationary waves to propagate from high latitudes to the south of the Yangtze River, which maintained as an energy source for the cyclonic circulation in situ. Under the control of the massive blocking high, cold air from high latitudes could march southward on a large scale, but continuously pervaded into the south. On the other hand, the SST in the western Pacific warm pool rose up constantly since the onset of the strong La Nina episode, which provided a source for warm and moist air. The blocking high collapsed around 30 January and the energy source for the local cyclonic circulation was cutoff. Thus, the precipitation in southern China stopped after 1 February.

关 键 词：ROSSBY波 大尺度环流 南方雪灾 阻塞高压 

分 类 号：P434[天文地球—大气科学及气象学] P448