The linkages between the weather and air-sea interactions in the vicinity of the Kuroshio Extension

by Nicholas Bond

Nick's interest is in better understanding the causes and effects of variations in air-sea interactions in western boundary current regions, especially in the vicinity of the Kuroshio Extension (KE).  A specific project currently underway (in collaboration with Meghan Cronin) is exploring how fluctuations in the surface heating in the recirculation gyre south of the KE relate to regional weather patterns.  There is a strong seasonality to these patterns since the net heating is dominated by the sensible and latent heat fluxes in winter and the solar insolation in summer.  The degree to which the weather variability controls the heat fluxes on day-to-day time scales versus seasonal to interannual time scales is being compared.  Our analysis of the short-term variability is based on direct observations from the Kuroshio Extension Observatory (KEO); analysis of the longer-term variability is based on synthetic data from the NCEP/NCAR Reanalysis Project and remotely-sensed data from the International Satellite Cloud Climatology Project (ISSCP).  As a natural extension of the research sketched out above, I am beginning a project to diagnose the atmospheric sensitivity to SST variations in the vicinity of the KE.  A series of NWP model experiments are planned, with an initial focus on the impacts of regional SST/heat flux anomalies during situations when tropical cyclones are undergoing transition to extratropical storms.  These transitions are important in that they appear to have significant influence on the atmospheric circulation well downstream over the central and eastern North Pacific.