Emergent Properties of Convection in OTREC and PREDICT

Abstract

Data from recent field programs studying deep convection may be useful in constraining cumulus parameterizations. To this end, gridded dropsonde analyses are made using data from the OTREC (Organization of Tropical East Pacific Convection) and PREDICT (PreDepression Investigation of Cloud-Systems in the Tropics) projects to characterize the mesoscale properties of tropical oceanic convection in terms of selected thermodynamic parameters computable from the explicit grids of large-scale models. In particular, saturation fraction, lower tropospheric moist convective instability, and convective inhibition appear to govern column-integrated moisture convergence, while sea surface temperature is related to the top-heaviness of mass flux profiles and the integrated entropy divergence. Local (as opposed to global) surface heat and moisture fluxes and convective available potential energy correlate weakly with these quantities. Recommendations to improve cumulus parameterizations are enumerated.