Midlatitude Atmospheric Response to Arctic Amplification Using Pre-Industrial Climate Model Integrations

Arctic Amplification (AA) states that the Arctic region is warming twice as fast as the global average. There could be potential effects that this mechanism has on our global climate, in particular, the mid-latitude general circulation. An increase of temperature and heavy rainfall has occurred since the 90's, however recently, extreme colds have taken over some mid-latitude regions. Some recent studies attributed the increased frequency of extreme weather events to AA while others disagreed. Therefore, this study aims to better understand the Northern Hemisphere (NH) mid-latitude atmospheric response in association with AA. A 500-year CMIP5 GFDL pre-industrial model integration is used. With composites of anomalously warm and anomalously cold years over the Arctic region, surface air temperature, zonal wind, precipitation and sea ice concentration were examined globally.We have found that the surface air temperature in general decreases in the NH mid-latitude continents (although not statistically significant) associated with anomalously warm Arctic years. In addition, the tropospheric jet stream shifts equatorward, in particular, over the North Pacific Ocean and the stratospheric polar vortex experiences cooling and acceleration. Anomalous precipitation is also identified in the tropical region as well as the NH mid-latitudes. The only significant region of sea ice concentration loss occurs over the Barents-Kara Sea. Similar conclusions are also found in the NCAR WACCM model integration.