大气科学2017，Vol.41Issue(4)：691-701,11.DOI:10.3878/j.issn.1006-9895.1612.16145
我国南方持续性低温与东亚冬季风“北弱南强”模态的关系
The Relationship between Persistent Cold Spell in Southern China and the Variation Mode of East Asian Winter Monsoon with Opposite Signs in the North and South
摘要
Abstract
In this paper,atmospheric circulation features for persistent cold spells in southem China are investigated and their connection with the opposite variation mode of East Asian Winter Monsoon (EAWM) in the south and north is discussed.Compared with cold waves,the persistent cold spells in southern China persist longer and occur more frequently.During the cold waves,the ridges and troughs form a typical wave train propagating through the Eurasian continent.During the cold spells,the major East Asian trough retreats to the north.According to locations and orientations of tilted ridges and associated troughs in the large-scale circulation at high-mid latitudes,zonal flows prevail in the mid latitudes over Asia,leading to the so called "western path" of cold air,i.e.cold airmass mainly come zonally from the west.In addition,the southern part of Japan is dominated by positive height anomalies,which block the cold air in the west and prolong the control of cold air over southern China,and thus lead to a persistent extreme low temperature spell in southern China.Besides,active perturbations in the southern branch of the jet stream also play an indispensable role in the event.In most of the previous studies,the Asian Winter monsoon was taken as a whole.However,recent works have shown that there mainly exist two modes of EAWM anomalies,i.e.the mode with the same sign of anomalies throughout the eastern part of China and that with opposite signs of EAWM anomalies in the south and north.With respect to these cold spells,the anomalous surface wind field is featured by variations with opposite signs,i.e.the north is under the control of anomalous southerly wind,while the south is under the control of anomalous northerly winds.This pattern corresponds to the second type of EAWM variability mode,which is different to the mode with the same sign of variation throughout the eastern part of China.For this mode,the northerly winds that lead to the drop of temperature in southern China are not caused by strong cold air intrusion from the high latitudes.Case studies also confirm the above results.关键词
东亚冬季风/南北反相模态/南方持续性低温Key words
East Asian winter monsoon/East Asian winter monsoon mode with opposite signs of variation in the south and north/Persistent cold events in southern China分类
天文与地球科学引用本文复制引用
彭京备,孙淑清..我国南方持续性低温与东亚冬季风“北弱南强”模态的关系[J].大气科学,2017,41(4):691-701,11.基金项目
国家自然科学基金41675086,公益性行业(气象)科研专项项目GYHY201406020,国家重点基础研究发展计划项目2012CB417205 National Natural Science Foundation of China (Grant 41675086),Special Fund for Meteorological Research in the Public Interest (Grant GYHY201406020),National Basic Research Program of China (Grant 2012CB417205) （气象）
