A Synthetic Aperture Radar–Based Climatology of Open-Cell Convection over the Northeast Pacific Ocean

Abstract

This paper presents an 8-yr (1999?2006) climatology of the frequency of open-cell convection over the northeastern Pacific Ocean and the thermodynamic and kinematic environment associated with its development. The climatology is based on synthetic aperture radar?derived wind speed images and reanalysis data. The climatology shows that open-cell convection was a cold-season phenomenon, having occurred in environments in which the difference in temperature between the near-surface air and the sea surface is negative and in environments with positive surface sensible and latent heat fluxes. Within the region between the surface and 500 hPa, the 700?850-hPa layer median static stability was near moist adiabatic while that for the remainder was conditionally unstable. The median magnitude of the vertical wind shear was largest in the 925-hPa?near-surface and 500?700-hPa layers while that at midlevels was relatively weak. Similarities are highlighted between the organization of open-cell convection over the northeastern Pacific Ocean and tropical deep moist maritime convection in terms of cold-pool dynamics. Avenues for future work are discussed.