Multi-Scale Impacts of Midlatitude Oceanic Frontal Zones on the Atmosphere (Invited Presentation)
In addition to those basin-scale atmospheric anomalies, sharp meridional contrasts in heat and moisture release from the ocean across the fronts along the Kuroshio Extension (KE) and Oyashio are found to leave meso-scale imprints on surface pressure, surface wind convergence, low-level cloudiness and precipitation, whose representation in reanalysis data is found highly sensitive to the resolution of SST field assigned for data assimilation. Interestingly, a surface baroclinic zone along the Oyashio front is maintained mainly by cross-frontal contrasts in sensible heat release, whereas a baroclinic zone along the KE is by advective effects of the converging surface northerlies into the meso-scale pressure trough. These meso-scale imprints of the fronts tend to undergo notable modulations interannually between the stable and unstable regimes of the KE path.
Under the monsoonal northerlies in winter, the warm Kuroshio also organizes shallow convective stratocumulus within the developed unstable mixed layer. The locally enhanced convective updraft acts to augment the super-saturation level, leading to modifications of cloud microphysical properties, including an increase in cloud droplet density and thereby a potential augmentation of cloud albedo.