Tropical convective variability in the CAPE phase space

Abstract

Abstract The relationship between pseudo‐adiabatic and reversible convective available potential energy (CAPE) in the tropical atmosphere is examined using the Tropical Ocean–Global Atmosphere programme (TOGA) Coupled Ocean–Atmosphere Response Experiment (COARE) radiosonde dataset. The effect of the ice phase and the dependence of the various CAPE quantities on surface variabilities is also examined. CAPE distribution is qualitatively different for the regimes with positive and negative reversible CAPE (rCAPE). The former is characterized by a strong linear relationship (synchronic line) with a slightly weaker increase of rCAPE than that of pseudo‐adiabatic CAPE, with its evolution primarily dictated by the surface moisture. This synchronic line also penetrates into the negative rCAPE regime, where CAPE distributes diffusively between this synchronic line and a line with zero reversible CAPE. These more complex distributions of CAPE in the negative rCAPE regime are explained by their dependence on the level of neutral buoyancy. Copyright © 2002 Royal Meteorological Society