Vertical Velocity and Diabatic Heating Top-Heaviness in the Convective Evolution Over Tropical Oceans

Convective heating and vertical motion are closely linked to each other and follow similar evolutionary paths over their convective life cycle. It has not yet been extensively explored, using observation, how such a collaborative evolution changes systematically from region to region over tropical oceans. In this study, the ERA5 reanalysis data and satellite measurements from Tropical Rainfall Measuring Mission Precipitation Radar are analyzed to examine the variability of the large-scale vertical velocity (ω) and diabatic heating ($Q_1$) profiles over tropical oceans. Hour-to-hour variability in these variables is examined based on composite time series to delineate the evolution of ω and $Q_1$ before and after Global Satellite Mapping of Precipitation (GSMaP) precipitation peaks. Four tropical basins are selected to study regional differences: western Pacific (WP), eastern Pacific (EP), Indian Ocean (IO), and Atlantic Ocean (AO). The composite time series reveal that the ω and $Q_1$ distributions align with the typical life cycle of mesoscale convective systems (MCSs). Empirical orthogonal function (EOF) decomposition is applied to the vertical structure of ω and $Q_1$ in terms of top-heaviness. The ω and $Q_1$ top-heaviness ratio (THR) delineate similar evolutionary curves in that THR enhances as convection intensifies, but the peak hour occurs earlier for $Q_1$ by several hours than for ω. The top-heaviness of ω and $Q_1$ exhibits a notable regionality that they are bottom-heavier in EP and AO than in WP and IO. Different rain types of shallow, deep convective, and stratiform are closely related to specific empirical orthogonal function modes in a regionally independent manner.