Atlantic Multi-decadal Oscillation (AMO) variability has been proposed to be an indispensable element of atmosphere–ocean–sea ice interactions. It can cause significant climate changes globally. For example, it has been shown to affect the East Asian winter and summer monsoons, and the precipitation and temperature in the United States, North Africa, and Europe. In Eurasia, it has been suggested that the SST anomalies (SSTAs), especially in the Atlantic Ocean, are partly responsible for changes in temperature, precipitation, and storminess through evaporation and atmospheric heating processes. Nevertheless, the relation between AMO and the wintertime Eurasian climate is still not entirely clear.  

Based on the observations and models’ simulation, Prof. WANG Huijun, Dr. HE Shengping and Dr. HAO Xin from Nansen-Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Sciences, explored the central Eurasian climate teleconnection with AMO in winter and then examined the mechanism using observations and simulations.  

Composite winter-mean surface air temperature anomalies in the warm (left panels) and cold (right panels) AMO periods (Image by IAP)

“We found that the winter SAT over central Eurasia (30°–70°E, 30°–50°N) shows significant positive anomalies during the warm AMO period but weak and insignificant anomalies in the cold AMO period.” Said Dr. HAO, “Such asymmetrical response to warm and cold AMO could also be found in the atmospheric circulation. For example, significant atmospheric anomalies that impact the central Eurasian winter temperature could be observed in warm AMO but barely appear in cold AMO.”  

Their results suggested that, compared with cold AMO, warm AMO could stimulate stronger Rossby waves which propagate from the North Atlantic eastward to Eurasia and then favor the teleconnection between the warm AMO and central Eurasian winter temperature. 

The study was published in Climate Dynamics.