乌拉尔阻塞高压的维持发展及其与2020/2021年冬季强寒潮活动的关系  

Maintenance and Development of Ural Blocking High and its Relationship with Severe Cold Wave Activities in 2020/2021 Winter

作　　者：彭京备[1] 孙淑清[1] 陈伯民[2] PENG Jingbei;SUN Shuqing;CHEN Bomin(International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;Shanghai Climate Center,Shanghai 200030)

机构地区：[1]中国科学院大气物理研究所国际气候与环境科学中心,北京100029 [2]上海市气候中心,上海200030

出　　处：《大气科学》2023年第5期1421-1433,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金重点项目41730959;国家重点研发计划项目2018YFC1505601;国家自然科学基金项目41975072。

摘　　要：2020年岁末至2021年初前后两次强寒潮侵入我国,引起大范围的强烈而持续的降温。本文对于其相应的环流特点及成因进行了分析研究,主要结论是:(1)从环流形势看,两次寒潮的发展过程,都是属于“横槽转竖”的类型。但是,自2020年的12月中旬至第二次寒潮结束,乌拉尔地区始终维持着宽广的高压脊(阻高),并未出现阻塞崩溃或不连续后退的现象。这与多数东亚地区寒潮爆发时的环流特点有差别。(2)乌拉尔阻塞高压及其脊前北风的加强和维持,使其前侧的斜压性大大加强。下游槽底的等高线日益密集,冷平流也不断发展,增强和向南推进。这些都推动了西伯利亚高压的加强和南扩。(3)在两次寒潮过程发生之前,源自0°E附近的低频静止波能量向东传播,有利于乌拉尔高压脊的维持、加强以及其下游低槽发展,为冷空气的向南爆发提供有利条件。Between late 2020 and early 2021,eastern China was struck by two consecutive cold waves,leading to an extensive,severe,and persistent drop in temperature.This paper explores the features and formation mechanisms of the circulation related to these two cold waves.The primary results are as follows:(1)The circulation patterns of these two cold waves are recognized as a type of“anticlockwise turning of the transverse trough.”However,a broad ridge(or blocking high)was maintained over the Ural region from mid-December 2020 to the end of the second cold wave.The blocking high did not experience a breakdown or“discontinuous westward shift”,which differentiates it from the common cold waves in eastern Asia.(2)The maintenance and strengthening of northerly winds downstream of the Ural high results in an increase in the baroclinicity in situ.In the region downstream of the Ural high,the gradient of the geopotential height contour in the south of the transverse trough rapidly increases,and the cold temperature advection consistently enhanced and southward advanced.The aforementioned phenomena cause the intensification and southward expansion of the Siberian High.(3)Before the occurrence of the two cold waves,the energy of a low-frequency stationary wave originating at 0°E(or the west)propagates eastward,which favors the maintenance and intensification of the Ural ridge and the development of the trough downstream,offering a favorable condition for the southward outbreak of cold air.

关 键 词：2020/2021 冬季 强寒潮 乌拉尔山阻塞 准静止波能量频散 

分 类 号：P448[天文地球—大气科学及气象学]