Modulation of Cyclones With Tropical and Extratropical Origins by Mesoscale SSTs in the Kuroshio Extension Region

Abstract

Abstract Two typical classes of cyclones originating from the tropics (ToCs) and extratropics (EoCs) with distinct preconditions, and passing the Kuroshio Extension (KE) region in cold season in the North Pacific are detected and tracked based on high‐resolution atmospheric simulations with and without mesoscale sea surface temperature (SST) forcing. A comparison between ToC‐to‐mesoscale SST and EoC‐to‐mesoscale SST responses indicates that the different cyclone development and the environmental water vapor restoration in the KE are primarily attributed to different ToC and EOC's preconditions. The higher initial intensity of ToCs leads to stronger atmospheric response to mesoscale SSTs and extended cyclone growth whilst the colder and drier precondition of EoCs induces stronger water vapor restoration in the KE after EoCs passing‐by. It is further demonstrated that the water vapor restoration is dominated by moisture convergence. The study provides new insights into the physical understanding of mesoscale SSTs' influence on cyclogenesis in the midlatitudes.

Keywords

• mesoscale SST
• cyclones
• Kuroshio Extension