Connections of Arctic Oscillation and warm pool SST variations during boreal winter

Arctic Oscillation (AO) is the most dominant variability of atmospheric circulation in the middle-to-high latitudes. On the other hand, the tropical western Pacific (TWP) plays an important role in both the tropical and extratropical climate by modulating tropical convection. In this study, we examine the connections between AO and warm pool sea surface temperature (SST) using the observations and the CMIP5 climate models. By analyzing the outgoing longwave radiation (OLR) and atmospheric diabatic heating, it is found that the sensitivity of convective forcing in response to anomalous SST variation in TWP significantly increases in recent decades. Because of this, the east-west zonal circulation has been modified, subsequently, the changes in the trend of both precipitation and OLR in the TWP. Furthermore, it is found that the SST variations in the TWP are closely associated with the AO-like atmospheric circulation in the middle-to-high latitudes, which is indicative of a strengthening of atmospheric circulation connecting the tropics-Arctic via atmospheric teleconnections.