广西一次冷空气过程前后Rossby波作用的对比分析  

Comparative analysis of Rossby wave before and after a cold air process in Guangxi

作　　者：覃皓 Qin Hao(Guangxi Meteorological Observatory,Nanning 530022,China)

机构地区：[1]广西壮族自治区气象台,南宁530022

出　　处：《气象研究与应用》2021年第4期38-43,共6页Journal of Meteorological Research and Application

基　　金：广西科技计划项目(桂科AB21075008);广西气象局短时临近天气预报技术创新团队项目。

摘　　要：基于T-N波作用通量以及NCEP/NCAR再分析资料,对比分析了2016年1月广西一次强冷空气过程前后两个阶段中大尺度环流以及Rossby波的调制作用。结果表明,冷空气活动过程前后阶段大气环流存在明显差异。第一阶段中欧亚中高纬地区阻塞形势明显,低纬度地区环流平直。第二阶段中欧亚低纬地区环流经向度增大,南支槽发展活跃;两个阶段中欧亚大陆上空均存在南北两支Rossby波列。第一阶段中北支波列调控了乌拉尔高压脊的发展以及横槽转竖,而南支波列调控了印缅槽的减弱,两者协同使冷空气更易南下。第二阶段南支波列主导了南支槽的发展东移,为该阶段降水提供了动力抬升以及水汽条件;NAO与南北两支波列的活动密切相关,NAO由负到正的位相转变是第二阶段南支波列增强的可能原因。The large-scale circulation and modulation of Rossby during two periods of a strong cold air process were comparative analyzed based on the T-N wave activity flux diagnosis by using ERA5 reanalysis data.The results showed that(1) there were significant differences in atmospheric circulation before and after this process. In the first stage, the blocking situation in the middle and high latitudes Eurasia was obvious while the patter in the low latitudes was straight. In the second stage, the circulation patter trended to more meridian in the low latitudes Eurasia and the southern branch trough(SBT) developed actively.(2) There were two Rossby wave trains located in the north and south Eurasia respectively during the two stages. The northern one regulated the development of the Ural ridge and the rotation of the transverse trough. The southern one modulated the weakening of the India-Burma trough. The synergy of the two Rossby wave trains made cold air reach the south easily in the first stage. The southern one dominated the development and eastward of the SBT, providing dynamic uplift and water vapor for precipitation in the second stage.(3) The NAO had a close relationship with the two wave trains. The phase transition of NAO from negative to positive is the possible reason for the strengthening of the southern one in the second stage.

关 键 词：ROSSBY波 冷空气 波作用通量 环流 

分 类 号：P458[天文地球—大气科学及气象学]