Simulated Influence of the Atlantic Multidecadal Oscillation on Summer Eurasian Nonuniform Warming since the Mid-1990s

• Published in: Advances in atmospheric sciences Vol. 36; no. 8; pp. 811 - 822
• Main Authors: Sun, Xueqian, Li, Shuanglin, Hong, Xiaowei, Lu, Riyu
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.08.2019; Springer Nature B.V; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Climate Change Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Department of Atmospheric Science, China University of Geosciences, Wuhan 430074, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China%Climate Change Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China%Climate Change Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China%State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
• Subjects: Advection; Amplification; Anticyclonic circulation; Atlantic Oscillation; Atmospheric circulation; Atmospheric circulation models; Atmospheric General Circulation Models; Atmospheric Sciences; Atmospheric variability; Climatology; Cloud cover; Computer simulation; Cyclonic circulation; Diabatic heating; Diagnostic systems; Earth and Environmental Science; Earth Sciences; Experiments; General circulation models; Geophysics/Geodesy; Heating; Meteorology; Original Paper; Precipitation; Radiation; Sea surface; Sea surface temperature; Short wave radiation; Summer; Surface temperature; Teleconnections; Tropical climate; Northeast Asia; West Asia; Central Asia; Europe; 不均匀增暖; 丝绸之路波列(SRP); Silk Road Pattern; 北大西洋多年代际振荡(AMO); nonuniform warming; Atlantic Multidecadal Oscillation
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-019-8169-z

Based on ensemble experiments with three atmospheric general circulation models (AGCMs), this study investigates the role of the Atlantic Multidecadal Oscillation (AMO) in shaping the summer nonuniform warming over the Eurasian continent since the mid-1990s. The results validate that the positive-phase AMO can indeed cause nonuniform warming, with predominant amplified warming over Europe-West Asia and Northeast Asia, but with much weaker warming over Central Asia. The underlying mechanism is then diagnosed from the perspective that the boundary forcing modulates the intrinsic atmospheric variability. The results highlight the role of the Silk Road Pattern (SRP), an intrinsic teleconnection pattern across the subtropical Eurasian continent propagating along the Asian jet. The SRP can not only be identified from the AGCM control experiments with the climatological sea surface temperature (SST), but can also be simulated by the AMO-related SST anomaly (SSTA) forcing. Furthermore, diagnostic linear baroclinic model experiments are conducted, and the results suggest that the SRP can be triggered by the AMO-related tropical diabatic heating. The AMO-triggered SRP-like responses feature anticyclonic circulations over Europe-West Asia and Northeast Asia, but cyclonic circulation over Central Asia. These responses cause increased warm advection towards Europe-West Asia and Northeast Asia, reduced precipitation and cloud cover, and then increased downward shortwave radiation. This increased warm advection and increased downward shortwave radiation together cause amplified warming in Europe-West Asia and Northeast Asia. The situation is opposite for Central Asia.