Atmospheric Response to Mesoscale Oceanic Eddies over the Kuroshio Extension：Case Analyses of Warm and Cold Eddies in Winter

The response of the atmosphere to mesoscale oceanic eddies is investigated by using dynamic composite and bandpass filters with particular focus on one warm eddy and one cold eddy over the Kuroshio Extension during the winter season. Results show positive correlation between sea surface temperature (SST) and wind speed at 10-m on dynamic composites, indicating remarkable oceanic forcing at daily time scales. Significantly weak divergence appears over the warm (cold) eddy center with positive (negative) vorticity anomaly. Latent and sensible heat fluxes increase (decrease) over the warm (cold) eddy, thus weakening (enhancing) atmospheric stability and thickening (thinning) the marine atmospheric boundary layer with strong (weak) vertical mixing. The maximum (minimum) center of frictional velocity, which represents turbulent viscous forces, lies over the warm (cold) eddy, indicating the substantial role of the vertical mixing mechanism in mesoscale and microscale ocean-atmosphere interaction. Mesoscale oceanic eddies can exert their influence on atmospheric transient disturbance intensity, which is significant both in the boundary layer and the mid-lower troposphere. Moreover, baroclinic energy conversion is found to play a critical role in the oceanic forcing of atmospheric transient disturbances.