Mechanisms for convection triggering by cold pools
Poster PDF
Authors
Zhiming Kuang — Harvard University
Giuseppe Torri — University of Hawai’i at Manoa
Category
Shallow-Deep Convective Transition
Description
Cold pools are fundamental ingredients of deep convection. They contribute to organizing the sub-cloud layer and are considered to play an important role in deep convective regimes by triggering new convective cells. It was long known that the triggering could happen mechanically, through lifting by the cold pools’ fronts. More recently, it has been suggested that convection could also be triggered thermodynamically, by accumulation of moisture around the edges of cold pools. A method based on a Lagrangian tracking algorithm is here proposed to disentangle the signatures of both forcings and quantify their importance in a given environment. Results from a simulation of radiative convective equilibrium over the ocean show that parcels reach their level of free convection through a combination of both forcings, each being relevant at different stages of the ascent. Mechanical forcing is an important player in lifting parcels from the surface, whereas thermodynamic forcing reduces the inhibition encountered by parcels before they reach their level of free convection.
