Definition of the core zone of the “westerlies-dominated climatic regime”, and its controlling factors during the instrumental period  

作　　者：HUANG Wei CHEN JianHui ZHANG XiaoJian FENG Song CHEN FaHu 

机构地区：[1]MOE Key Laboratory of West China's Environmental System, Lanzhou University [2]Department of Geosciences, University of Arkansas

出　　处：《Science China Earth Sciences》2015年第5期676-684,共9页中国科学（地球科学英文版）

基　　金：supported by National Basic Research Program of China(Grant No.2010CB950202);National Natural Science Foundation of China(Grant No.41130102);Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120211130001);Fundamental Research Funds for the Central Universities(Grant No.LZUJBKY-2014-119);the Open Foundation of MOE Key Laboratory of Western China’s Environmental System,Lanzhou University(Grant No.LZUJBKY-2013-BT01)

摘　　要：The term "westerlies-dominated climatic regime" describes the pattern of precipitation/moisture variations between westerliesdominated arid Central Asia(ACA) and mid-latitude monsoon-dominated Asia on decadal to multi-millennial time scales. However, no attempts have been made to define its core region and the possible physical mechanisms responsible during the period of instrumental observations. The present study investigates the spatiotemporal variations of summer and winter precipitation on interannual to decadal time scales over mid-latitudes of the Eurasian continent using Empirical Orthogonal Function(EOF) analysis. Our results suggest the existence of an opposing pattern of summer precipitation variations between ACA and mid-latitude monsoon-dominated Asia and Mediterranean on decadal time scales. Based on these results, the core region influenced by the westerlies is outlined, including arid central Asia and Xinjiang in China(36°–54°N, 50°–90°E). By using monthly NCEP-NCAR reanalysis, the relationship between the "westerlies-dominated climatic regime" and atmospheric circulation were also analyzed. The combination of the zonal climatic teleconnection pattern and anomalous Indian Summer Monsoon Precipitation(ISMP) causes the precipitation characteristics of the "westerlies-dominated climatic regime" precipitation pattern. In addition, the Atlantic Multidecadal Oscillation(AMO) may also have an important effect on the "westerlies-dominated climatic regime".The term ＂westerlies-dominated climatic regime＂ describes the pattern of precipitation/moisture variations between westerlies- dominated arid Central Asia （ACA） and mid-latitude monsoon-dominated Asia on decadal to multi-millennial time scales. However, no attempts have been made to define its core region and the possible physical mechanisms responsible during the period of instrumental observations. The present study investigates the spatiotemporal variations of summer and winter precip- itation on interannual to decadal time scales over mid-latitudes of the Eurasian continent using Empirical Orthogonal Function （EOF） analysis. Our results suggest the existence of an opposing pattern of summer precipitation variations between ACA and mid-latitude monsoon-dominated Asia and Mediterranean on decadal time scales. Based on these results, the core region in- fluenced by the westerlies is outlined, including arid central Asia and Xinjiang in China （36°-54°N, 50°-90°E）. By using monthly NCEP-NCAR reanalysis, the relationship between the ＂westerlies-dominated climatic regime＂ and atmospheric cir- culation were also analyzed. The combination of the zonal climatic teleconnection pattern and anomalous Indian Summer Monsoon Precipitation （ISMP） causes the precipitation characteristics of the ＂westerlies-dominated climatic regime＂ precipita- tion pattern. In addition, the Atlantic Multidecadal Oscillation （AMO） may also have an important effect on the ＂wester- lies-dominated climatic regime＂.

关 键 词：core zone of the ＂westerlies-dominated climatic regime＂ decadal.interannual Atlantic Multidecadal Oscillation（AMO） Indian Summer Monsoon Precipitation （ISMP） 

分 类 号：P461[天文地球—大气科学及气象学]