Asymmetric Relationship between the Meridional Displacement of the Asian Westerly Jet and the Silk Road Pattern  

作　　者：Xiaowei HONG Riyu LU Shuanglin LI 

机构地区：[1]Climate Change Research Center, Chinese Academy of Sciences, Beijing 100029, China [2]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China [3]University of the Chinese Academy of Sciences, Beijing 100049, China [4]Nansen-Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China [5]Department of Atmospheric Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China

出　　处：《Advances in Atmospheric Sciences》2018年第4期389-396,共8页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41320104007, 41421004, and 41731177)

摘　　要：In previous work, a significant relationship was identified between the meridional displacement of the Asian westerly jet （JMD） and the Silk Road Pattern （SRP） in summer. The present study reveals that this relationship is robust in northward JMD years but absent in southward JMD years. In other words, the amplitude of the SRP increases with northward displacement of the jet but shows little change with southward displacement. Further analysis indicates that, in northward JMD years, the Rossby wave source （RWS） anomalies, which are primarily contributed by the planetary vortex stretching, are significantly stronger around the entrance of the Asian jet, i.e., the Mediterranean Sea-Caspian Sea area, with the spatial distribution being consistent with that related to the SRP. By contrast, in southward JMD years, the RWS anomalies are much weaker. Therefore, this study suggests that the RWS plays a crucial role in inducing the asymmetry of the JMD-SRP relationship. The results imply that climate anomalies may be stronger in strongly northward-displaced JMD years due to the concurrence of the JMD and SRP, and thus more attention should be paid to these years.In previous work, a significant relationship was identified between the meridional displacement of the Asian westerly jet （JMD） and the Silk Road Pattern （SRP） in summer. The present study reveals that this relationship is robust in northward JMD years but absent in southward JMD years. In other words, the amplitude of the SRP increases with northward displacement of the jet but shows little change with southward displacement. Further analysis indicates that, in northward JMD years, the Rossby wave source （RWS） anomalies, which are primarily contributed by the planetary vortex stretching, are significantly stronger around the entrance of the Asian jet, i.e., the Mediterranean Sea-Caspian Sea area, with the spatial distribution being consistent with that related to the SRP. By contrast, in southward JMD years, the RWS anomalies are much weaker. Therefore, this study suggests that the RWS plays a crucial role in inducing the asymmetry of the JMD-SRP relationship. The results imply that climate anomalies may be stronger in strongly northward-displaced JMD years due to the concurrence of the JMD and SRP, and thus more attention should be paid to these years.

关 键 词：Asian westerly jet meridional displacement Silk Road Pattern asymmetric relation Rossby wave source 

分 类 号：P442[天文地球—大气科学及气象学]