Mesoscale wind divergence profiles in tropical convection

Abstract

Vertical air motion and its complement, horizontal wind divergence, carry most of the observable information about vertical profiles of heating in the tropics, but are challenging to measure accurately. We examined ~100km divergence at hourly resolution from several months of Doppler radar data in tropical convection regions. Two familiar signals -- convective and stratiform rain -- are easily seen in cases and readily isolated in statistics. More novel are divergence observations associated with sublimation and melting of snow in the upper troposphere, and unusual profiles in a tropical storm and a convectively coupled gravity wave. The waviness of divergence profiles suggests that the troposphere behaves importantly as a vertical spectral domain, not just a set of altitudes where processes may independently occur, with potential implications for long-range vertical cloud overlap.