Abstract:By using NOAA daily optimum interpolation sea surface temperature (SST) data and NCEP/NCAR daily atmospheric reanalysis data, this paper analyzes the seasonal variation of Kuroshio Extension SST front and its influence on the Pacific storm track. The results show that the seasonal variation of the SST front position is weak, but its strength has significantly strong seasonal variation, and the strength of Pacific storm track has a coordinated change with the strength of SST front in Kuroshio Extension. The SST front is the strongest in winter, enhancing the baroclinicity of the atmosphere above it. The baroclinic energy conversions from mean available potential energy to eddy available potential energy and from eddy available potential energy to eddy kinetic energy are increased in the Kuroshio Extension region, where the baroclinic eddies are generated more frequently, absorbing energy from the background mean flow during the process of moving downward along with west wind, and, finally, strengthening the Pacific storm track and anchoring the central axis of the storm track above the Kuroshio Extension region. The SST front is very weak in summer, weakening the baroclinicity of the atmosphere above. The baroclinic energy conversions from mean available potential energy to eddy available potential energy and from eddy available potential energy to eddy kinetic energy are greatly reduced, and baroclinic eddies are generated less frequently, weakening the Pacific storm track, and making the strength center move to central Pacific, located northward.