摘要：The net heat fluxand meridional temperature advection in the ocean are two factors in theNorth Pacific subtropical sea surface temperature front (NPSTF) frontogenesisoccurring from October to the following February. However, the relativeimportance of these two factors has been rarely explored. In this study,frontogenesis of the NPSTF is examined quantitatively based on themixed-layer heat budget equation to clarify the relative importance of netheat flux and meridional temperature advection and to further explore itsconnection with the atmosphere above. Diagnosis results show that the netheat flux dominates the frontogenesis from October to December, while themeridional temperature advection in the ocean contributes equally as or evenmore than the net heat flux in January and February. The atmosphere iscritical to the frontogenesis of the NPSTF, including the direct effect ofthe net heat flux and the indirect effect through the Aleutian low. Furtheranalyses demonstrate that the latent heat flux (the shortwave radiation)dominates the net heat flux in October (from November to February). Themeridional temperature advection in the ocean is mostly due to the meridionalEkman convergence, which is related to the Aleutian low. Climatologically,the strengthening and southward migration of the Aleutian low from October tothe following February are characterized by the acceleration and southwardshift of the westerly wind to the south, respectively, which can drivesouthward ocean currents. Correspondingly, the southward ocean currentsprovide for colder meridional advection to the north of the NPSTF in Januaryand February, favoring frontogenesis. In addition, the Aleutian low plays arole in transforming the dominant effect of the net heat flux into the jointeffect of meridional temperature advection and net heat flux in January.
