Environmental control of deep convective clouds on Titan: The combined effect of CAPE and wind shear on storm dynamics, morphology, and lifetime

Abstract

AbstractTitan has deep convective clouds driven by the release of latent from methane condensation. As on Earth, the presence of convective available potential energy (CAPE), which quantifies the amount of energy available through condensation, is required for storms to develop. While CAPE is a requirement for storms, the dynamics, morphology, and longevity of storms on Earth is controlled by both CAPE and wind shear, often expressed as a ratio in the form of the bulk Richardson Number. The impact of CAPE and wind shear on storms in a Titan‐like environment are explored through numerical simulation. Model results indicate that Titan storms should respond to changes in the Richardson Number in a manner similar to storms on Earth. Very long‐lived storms (>24 h) propagating for 1000 km or more might be possible on Titan when CAPE and wind shear are properly balanced. Some of the simulated storms exhibit dynamics similar to squall lines. Varying amounts of shear in the Titan environment might explain the variety of convective cloud expressions—varying from short‐lived single cell storms to longer‐lived linear features and large cloud bursts—identified in Cassini orbiter and ground‐based observations. The varying amounts and spatial distribution of precipitation, as well as surface winds associated with storms, should have implications on the formation of fluvial and aeolian features and on the exchange of methane with the surface and lakes.