冬季乌拉尔山地区不同生命期阻塞高压的热动量输送特征  

The Characteristics of Thermal and Momentum Transport During the Different Lifetimes of Ural Blocking Highs inWinter

作　　者：路瑶[1] 李旭[1] 李艳[1] 陈艳[1] LU Yao;LI Xu;LI Yan;CHEN Yan(Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province,College of Atmospheric Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]甘肃省干旱气候变化与减灾重点实验室/兰州大学大气科学学院,甘肃兰州730000

出　　处：《高原气象》2022年第3期671-683,共13页Plateau Meteorology

基　　金：国家重点研发计划项目(2019YFA0606801);国家自然科学基金项目(41775051)。

摘　　要：冬季乌拉尔山地区阻塞高压(以下简称乌山阻高)是引发东亚地区寒潮天气的重要天气系统,研究其动力机制可为实际业务工作中的极端低温事件的预测提供更多的理论参考。本文利用美国国家环境预测中心-能源部(National Centre from Environmental Prediction-Department of Energy,NCEP-DOE)的再分析数据,采用天气学方法从1979-2018年40个冬季中甄选出21次短中(生命期5~7天)及14次长生命期(生命期等于或大于8天)乌山阻高,对比分析两类阻高过程中定常热(v*T*)、动量(u*v*)通量的输送特征,结果表明:(1)冬季长生命期阻高期间60°N附近v*T*的辐合量及u*v*输送量显著大于短中生命期的,说明定常热、动量输送对阻高的长时间维持有重要作用。且长生命期阻高期间对流层上层(300~150 hPa)20°N-40°N区域u*v*向北输送,短中生命期的则向南输送,说明副热带急流向中纬度输送u*v*为阻高长时间维持提供动量补充。同时冬季长生命期阻高期间70°N极锋急流偏弱,为阻高延长生命期,扩大范围提供有利条件。(2)定常热、动量通量在对流层中上层各层次上的分布也有显著不同。各层次上的v*T*及u*v*的输送都是通过阻高激发的Rossby波波列完成的。对流层中上层(500~300 hPa)乌山阻高关键区西北-东南域定常动量通量向极补充输送是阻高长时间维持的关键。The Ural blocking high(UB)is an important weather system that triggers the cold wave weather in the East Asia.Studying the dynamic mechanism of it provides more theoretical references for the forecast of extreme low temperature events in the practical business work.By used the reanalysis data from National Centre from Environmental Prediction-Department of Energy(NCEP-DOE),21 short-medium(the lifetime is about 5~7 days)and 14 long duration(the lifetime is equal to or greater than 8 days)UB are selected in winter during 1979-2018 according to the method of synoptic definition,and the characteristics of stationary thermal(v*T*)and momentum flux(u*v*)transport are compared and analyzed during the lifetime of the two types of blocking highs.The results show that:(1)The convergence of stationary thermal flux and the transport of the stationary momentum around 60°N during the lifetime of long duration UB in winter are significantly larger than it in the short-medium duration UB,indicating that the transport of stationary thermal and momentum flux plays an important role in the maintenance of the blocking highs.And the u*v*on the upper troposphere(300~150 hPa)in the 20°N-40°N region is transported poleward,but it is transported southward during the lifetime of the shortmedium duration UB.It shows that the u*v*from the subtropical jets provides momentum support for the maintenance of the UB.Meanwhile,the polar front jets near 70°N during the long life blocking highs in winter are weaker,providing favorable conditions for the UB to extend its duration and expand its range.(2)The distribution of stationary thermal and momentum flux on the different levels in the upper-middle troposphere is also significantly different.The transport of stationary thermal and momentum flux on the upper-middle troposphere is accomplished by Rossby wave train with blocking highs stimulating.The poleward transport of u*v*in the northwest-southeast region of the Ural key areas on the upper-middle troposphere which increases and replenishes i

关 键 词：乌山阻高 定常热、动量通量 副热带急流 极锋急流 Rossby波列 

分 类 号：P433.2[天文地球—大气科学及气象学]