An Investigation of the Effect of SST Mesoscale Variability on the Dynamics of the North Pacific Jet Stream and Storm Track

Abstract

The effect of SST mesoscale variability on the dynamics of the North Pacific Jet Stream and Storm track is investigated based on simulations with a global atmospheric circulation model coupled to a slab ocean model. The investigation is carried out by comparing time- and ensemble-averaged terms of the atmospheric eddy kinetic energy for two ensembles. The difference between the two ensembles is that SST mesoscale variability is retained in only one of them. It is found that SST mesoscale variability has a major effect on both the baroclinic and barotropic energy conversion processes in the atmosphere. For the investigated two-week period in the North Pacific, the net effect of the changes in the energy conversion processes on the jet stream is similar to that of a drag force. In addition, baroclinic energy conversion is suppressed and the eddy kinetic energy is reduced along the storm track.