Mechanisms Determining the Atmospheric Response to Sea Surface Temperature Anomalies

Abstract A simple model is used to study the mechanisms which control the local and remote (teleconnection) response of the atmosphere to the thermal forcing resulting from sea surface temperature (SST) anomalies located at various latitudes. The model chosen is a linear baroclinic spherical primitive equation model containing a zonally symmetric basic state with horizontal and vertical shear. An iterative procedure is developed in which the total diabatic heating resulting from the initial heating by the SST anomaly is calculated via feedbacks between the heating and the dynamic response of the system. Depending on the latitudinal location of the SST anomaly, two major limits of atmospheric response may be identified. The first, the “diabatic limit”, occurs with the SST anomaly embedded in weak low-latitude basic flow and results in a strong enhancement of the initial anomaly response through a vigorous positive dynamics-diabatic beating feedback. Strong teleconnections are evident between low and high l...