A numerical modelling investigation of the role of diabatic heating and cooling in the development of a mid-level vortex prior to tropical cyclogenesis – Part 1: The response to stratiform components of diabatic forcing

• Published in: Atmospheric chemistry and physics 2018-10, Vol.18 (19), p.14393-14416
• Main Authors: Nicholls, Melville E, Pielke Sr., Roger A, Wheeler, Donavan, Carrio, Gustavo, Smith, Warren P
• Format: Article
• Language: English
• Subjects: Adiabatic; Amplification; Angular momentum; Anvils; Ascent; Cells; Components; Computer simulation; Conservation; Conservation of angular momentum; Convective activity; Convective cells; Convective vortices; Cooling; Cyclogenesis; Cyclones; Diabatic cooling; Diabatic heating; Evaporation; Heating; Heating and cooling; Hydrometeors; Ice environments; Inflow; Mathematical models; Melting; Mesoscale convective vortices; Mesoscale vortexes; Microphysics; Modelling; Momentum; Numerical simulations; Ocean circulation; Physics; Removal; Simulation; Sublimation; Surface wind; Thermodynamic processes; Tropical climate; Tropical cyclogenesis; Tropical cyclones; Tropical depressions; Troposphere; Upper troposphere; Vortex motion; Vortices; Winds
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-18-14393-2018

Mid-tropospheric mesoscale convective vortices have been often observed to precede tropical cyclogenesis. Moreover, recent cloud-resolving numerical modelling studies that are initialized with a weak cyclonic mid-tropospheric vortex sometimes show a considerable intensification of the mid-level circulation prior to the development of the strong cyclonic surface winds that characterize tropical cyclogenesis. The objective of this two-part study is to determine the processes that lead to the development of a prominent mid-level vortex during a simulation of the transformation of a tropical disturbance into a tropical depression, in particular the role of diabatic heating and cooling. For simplicity simulations are initialized from a quiescent environment. In this first part, results of the numerical simulation are described and the response to stratiform components of the diabatic forcing is investigated. In the second part, the contribution of diabatic heating in convective cells to the development of the mid-level vortex is examined.