15:50 〜 16:10
[ACG33-13] On the influence of sea surface temperature fronts in the Kuroshio and Gulf Stream on cyclone development
★Invited Papers
キーワード：Kuroshio, Extratropical cyclone, SST front, Gulf Stream, Surface fluxes
The sea surface temperature (SST) distribution in the Kuroshio and Gulf Stream region have been argued to modulate the development of extratropical cyclones through sensible and latent heat fluxes. However, the direct and indirect effects of these surface fluxes of these fluxes on extratropical cyclones are still not well understood.
Using reanalysis data, idealized modelling, and theory, we show that the direct influence of sensible and latent heating on extratropical cyclones is negligible and not sensitive to the sharpness of the SST front. While the indirect effect of sensible heat fluxes in providing near-surface atmospheric baroclinicy along the SST front can play a role, the dominant factor appears to be the indirect effect of latent heat fluxes. The indirect influence of latent heat fluxes is proportional to the absolute SST downstream of developing cyclones, where surface evaporation provides latent heat for cyclone development. This might also partially explain why only less than half of the air-sea heat exchange along the Kuroshio and Gulf Stream are directly associated with active cyclones in these regions, as most of the heat exchange occurrs outside of the radius of influence of developing cyclones.
Using reanalysis data, idealized modelling, and theory, we show that the direct influence of sensible and latent heating on extratropical cyclones is negligible and not sensitive to the sharpness of the SST front. While the indirect effect of sensible heat fluxes in providing near-surface atmospheric baroclinicy along the SST front can play a role, the dominant factor appears to be the indirect effect of latent heat fluxes. The indirect influence of latent heat fluxes is proportional to the absolute SST downstream of developing cyclones, where surface evaporation provides latent heat for cyclone development. This might also partially explain why only less than half of the air-sea heat exchange along the Kuroshio and Gulf Stream are directly associated with active cyclones in these regions, as most of the heat exchange occurrs outside of the radius of influence of developing cyclones.