Estimates of geographic variability in vertical motion profile bottom-heaviness

Abstract:

The vertical structure of deep convection is highly variable geographically and temporally and strongly influences interactions with larger-scale circulations. We compare several estimates of the top-heaviness of the climatological vertical motion profiles in the intertropical convergence zone from reanalyses and satellite data. One satellite estimate is based on using observed surface convergence and precipitation (Handlos and Back, 2014), while another is based on the vertical profile of reflectivity. These estimates are compared with geographic variability in stratiform and shallow rain fractions. TRAIN algorithm latent heating retrievals are used to examine the extent to which geographic variability can be attributed to variations in stratiform rain fraction, variations in the convective heating profile, and/or variations in the stratiform heating profile. We find that in TRAIN, variations in top-heaviness are predominantly associated with variations in depth of the convective heating profile.