Gross Moist Stability Assessment during TOGA COARE: Amplification and Decay of

Daily averaged TOGA COARE data are analyzed to test our hypothesis that convection is amplified (attenuated) via sub-critical (super-critical) gross moist stability which corresponds to a bottom-heavy (top-heavy) vertical velocity profile. Gross moist stability (GMS) is a quantity which represents efficiency of moist static energy (MSE) export by convection and associated large-scale circulations. It is hypothesized that a bottom-heavy vertical velocity profile with negative GMS imports MSE efficiently and enhances the convection, and in contrast that a top-heavy profile with positive GMS exports MSE from the atmospheric column, attenuating the convection. In order to test this hypothesis, precipitation changes and probabilities of precipitation increase are plotted as a function of the GMS. This analysis verifies that negative (positive) GMS corresponds to an increase (a decrease) in precipitation, which is consistent with the hypothesis. Furthermore, we find that values of the GMS are related to convective life-cycles, in which convection starts with a structure having high efficiency of MSE import (negative and large GMS), the MSE-import efficiency reduce