2020/2021年冬季三次全国型强冷空气过程及其低频特征  

Three Cold Surges in China during the Winter of 2020/2021 and Their Low-Frequency Features

作　　者：袁媛[1] 申乐琳 晏红明[2] 洪洁莉 YUAN Yuan;SHEN Lelin;YAN Hongming;HONG Jieli(China Meteorological Administration Key Laboratory for Climate Prediction Studies,National Climate Center,Beijing 100081;Yunnan Climate Center,Kunming 650032)

机构地区：[1]中国气象局气候预测研究重点开放实验室,国家气候中心,北京100081 [2]云南省气候中心,昆明650032

出　　处：《大气科学》2023年第5期1557-1575,共19页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目U1902209、41776039。

摘　　要：2020/2021年冬季,东亚地区的强冷空气过程多次爆发,持续强降温及伴随的大风、雨雪天气给人民生产生活造成了严重影响。利用日尺度大气环流格点数据和地面气温站点资料,从次季节变化角度揭示了西伯利亚高压的低频振荡特征及对三次全国型强冷空气过程(2020年12月13~15日、2020年12月29日至2021年1月1日、2021年1月6~8日)的重要影响。研究显示,2020/2021年冬季,西伯利亚高压和中国东部地区气温变化都表现出明显的准双周(10~30 d)和30~60 d低频振荡特征,并且低频特征在冬季前期明显强于冬季后期。但是,三次强冷空气过程中低频振荡的特征各不相同,其中,第一次过程中准双周振荡有显著的正贡献,但30~60 d低频振荡为负贡献;而第二次和第三次过程兼有准双周和30~60 d低频振荡的共同作用,尤其第三次过程处于这两个低频波段的最强时期,这也导致第三次冷空气过程的降温幅度最大、低温影响范围最广,西伯利亚高压也发展最强。10~30 d低频西伯利亚高压的增强超前一候(5天)左右对冷空气爆发和中国东部地区强降温均有显著的负相关关系,其中与冷空气爆发的关系超前1~2天最显著,与中国东部地区低温的关系超前2~3天最为显著。During the 2020/2021 winter,strong cold air processes frequently emerged in East Asia,resulting in persistently low temperature,strong wind,heavy snow and rainfall,and serious impacts on the people’s production and life in China.Using the daily atmospheric circulation grid data and station temperature data,this paper revealed the lowfrequency characteristics of the Siberian high(SH)and its significant impact on the three strong cold surges in China(Dec 13–15,2020;Dec 29,2020–Jan 1,2021;and Jan 6–8,2021).Both the SH and temperature in eastern China showed significant quasi-biweekly(10–30 d)and 30–60 d low-frequency oscillation(LFO)features,stronger in the earlier than the later winter of 2020/2021.However,the specific LFO features were totally different among the three cold surges.In the first one,the quasi-biweekly oscillation exhibited a significant positive contribution,while the 30–60 d LFO showed a negative contribution.However,the second and third cold surges experienced a combined effect of quasi-biweekly and 30–60 d LFO.The third one was in the strongest period of the above two LFO waves,also leading to the largest cooling range and the widest low-temperature range in China and the strongest SH development.The enhanced quasi-biweekly SH displayed a significant impact on the cold air outbreak and the strong cooling in eastern China by about one pentad(5 days)ahead,with its most significant impact on the cold air outbreak 1–2 days earlier and on the low temperature in eastern China 2–3 days earlier.

关 键 词：西伯利亚高压 准双周 30~60 d 低频振荡 全国型强冷空气 低温事件 

分 类 号：P466[天文地球—大气科学及气象学]