A general circulation model study of the atmospheric response to extratropical SST anomalies observe

Abstract A 30-year experiment with an atmospheric general simulation model has been performed. The lower boundary condition at all oceanic grid points between 38°S and 60°N has been prescribed to follow the observed month-to-month variation of the sea surface temperature (SST) field during the 1950–79 period. Much of the model diagnosis presented here pertains to the midlatitude atmospheric response to recurrent SST patterns in the North Pacific and North Atlantic in winter. The principal modes of variability of the seasonally averaged 515 mb height and SST fields have been identified using rotated principal component (RPC) analysis. The extrema of the first atmospheric mode reside over the North Atlantic and Eurasia, whereas the second mode is associated with height anomalies in the North Pacific/North American sector. Cross-correlation analysis reveals that these two atmospheric modes am linked to leading patterns of the SST field in the North Atlantic and North Pacific, respectively. It is also demonst...