Revisiting Tropical Cumulus Congestus Cloud Growth

Abstract:

Cumulus congestus represent a significant mode of convective cloud occurrence in the tropics. We use observations from the ARM Climate Research Facility sites in the tropical Western Pacific to investigate the growth of cumulus congestus clouds and the factors that control their lifecycle. Using a combination of geostationary satellite observations and vertically pointing cloud radar observed Doppler velocities, we define the state (terminal versus transient) of cloud growth in order to put complementary retrievals in proper context. We then investigate how cloud parcel buoyancy and bulk entrainment of individual clouds are impacted by environmental conditions. We use the results to expand upon our research on the relative importance of freezing layer stability and mid-tropospheric dry layers in limiting the growth of terminal cumulus congestus.