Environment and the Lifetime of Tropical Deep Convection

Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation Objective ● To assess the role of various mechanisms of interactions with the environment on the lifetime of tropical convective systems Approach ● Apply a cloud-tracking algorithm to tropical convective systems simulated by a regional highresolution model ● Document environmental conditions before and after convective systems initiate over ocean and land ● Quantify the comparative roles of various mechanisms of convection –environment interaction on the longevity of convective systems Hagos S, Z Feng, S Mc. Farlane and LR Leung. 2013. “Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation. ” Journal of the Atmospheric Sciences 70(8): 2409– 2425. Surface sensible heat fluxes (Wm-2 ) over (a) ocean and (b) land. The solid line marks the location of the propagating composite convective system. Impact ● Mid-tropospheric moisture before and after convective initiation positively relates to lifetime of convection systems ● For systems of equal lifetime, those over land tend to be more intense than those over ocean especially during the early stages of their life cycle ● Land convective systems suppress surface fluxes, while convective systems over ocean enhance them ● Convection transports momentum vertically, increasing low -level shear and decreasing upper level shear, both over ocean and land, though shear has little effect on the lifetime of the system