当前位置： 首页»科研成果» 2016 孙诚、李建平与合作者在Clim Dyn上发表论文 全球院

Cold season Africa–Asia multidecadal teleconnection pattern and its relation to the Atlantic multidecadal variability

Cheng Sun^{1, 2}. Jianping Li^{1, 2}. Ruiqiang Ding^3,4. Ze Jin⁵

1 College of Global Change and Earth System Science (GCESS), Beijing Normal University, Beijing 100875, China

2 Joint Center for Global Change Studies, Beijing 100875, China

3 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

4 Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, Chengdu University of Information Technology, Chengdu 610225, China

5 Department of Atmospheric Science, Yunnan University, Kunming 650091, China

Abstract

A prominent teleconnection pattern of multidecadal variability of cold season (November to April) upperlevel atmospheric circulation over North Africa and Eurasia (NA–EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data. This teleconnection pattern is characterized by an eastward propagating wave train with a zonal wavenumber of 5–6 between 20° and 40°N, extending from the northwest coast of Africa to East Asia, and thus is referred to as the Africa–Asia multidecadal teleconnection pattern (AAMT). One-point correlation maps show that the teleconnectivity of AAMT is strong and further demonstrate the existence of the AAMT. The AAMT shapes the spatial structure of multidecadal change in atmospheric circulation over the NA–EA region, and in particular the AAMT pattern and associated fields show similar structures to the change occurring around the early 1960s. A strong in-phase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. Barotropic modeling results suggest that the upper-level Rossby wave source generated by the AMV can excite the AAMT wave train, and Rossby wave ray tracing analysis further highlights the role of the Asian jet stream in guiding the wave train to East Asia. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability. The AMV is closely related to the coordinated change in surface and tropospheric air temperatures over Northwest Africa, the Arabian Peninsula and Central China, which may result from the adiabatic expansion/compression of air associated with the AAMT.

Keywords Atlantic multidecadal variability · Africa–Asia multidecadal teleconnection pattern · Rossby wave train · Africa–Asia multidecadal climate variability

Published By : Clim Dyn, online, doi: 10.1007/s00382-016-3309-y

Source: link.springer.com/content/pdf/10.1007/s00382-016-3309-y.pdf