The shallow-to-deep transition in convective clouds during GOAmazon 2014/5
Poster PDF
Authors
Michael Jensen — Brookhaven National Laboratory
Scott Giangrande — Brookhaven National Laboratory
Cari Gostic — Cornell University
David B. Mechem — University of Kansas
Category
GoAmazon – Clouds and aerosols in Amazonia
Description
The lifecycle of convective clouds, particularly the transition from shallow to deep convection and the environmental controls of this transition, are poorly understood and not represented well in climate model simulations. Nearly two years of observations from the ARM Mobile Facility (AMF) taken during GOAmazon 2014/5 campaign are analyzed in order to investigate the environmental conditions controlling the transition from shallow to deep convective clouds. The ARSCL value-added data product is used to qualitatively define two subsets of convective clouds: 1) Transition cases, where a period of shallow convective clouds is followed by a period of deep convective clouds and 2) Non-transition cases, where shallow convective clouds persist without any subsequent deeper development. For these two subsets, observations of the time varying thermodynamic properties of the atmosphere, including surface heat and radiative fluxes, and profiles of atmospheric state variables, are composited to define averaged properties for each transition state. Initial analysis indicates that the presence of a transition depends strongly on the pre-dawn mid-level humidity, convective inhibition, and surface temperature and humidity with little dependence on the convective available potential temperature and surface heat fluxes.
