Tropical Cyclone Convection and Tropical Cyclogenesis
Final Report Abstract
Idealized, high-resolution (500m horizontal grid spacing), numerical simulations were used to investigate the evolution of convective structures during tropical cyclogenesis. The simulations all began with a weak initial axisymmetric cloud-free vortex in a quiescent environment, but differ in the moisture level of the initial sounding and whether or not ice microphysical processes are considered. Irrespective of experimental setup, there is only a short period where shallow or congestus clouds dominate. The shallow cloud phase is slightly extended with the drier initial environmental sounding. The composite structure of the convective elements sampled changes markedly throughout the genesis period. For much of the genesis phase, vertical profiles of the mean convective cell show significant amounts of anticyclonic vorticity produced in cells in the inner core. Towards the end of the genesis phase, there is a large increase in the production of cyclonic vertical vorticity in inner-core convection, and cyclonic vorticity becomes dominant at low-mid levels. The evolution from roughly equal strength vertical profiles of cyclonic/anticyclonic vorticity at low-mid levels to profiles where cyclonic vorticity dominates occurs at relatively low system wind speeds (Vmax less than 10 m/s). This finding indicates a change in the structure of vortical convection prior to rapid intensification.
Publications
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2020: Recent Advances in Research on Tropical Cyclogenesis. Tropical Cyclone Research and Review, Volume 9, Issue 2, 87-105
Tang B, Fang J, Bentley A, Kilroy G, Nakano M, Park MS, Rajasree VPM, Wang Z, Wing A, Wu L
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2019: Control of Convection in High-Resolution Simulations of Tropical Cyclogenesis. J. Adv. Model. Earth Syst., 11, 1582-1599
Raymond D and Kilroy G
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2019: Tropical cyclogenesis at and near the Equator. Quart. J. Roy. Meteor. Soc. 145, 1846-1864
Steenkamp SC, Kilroy G, Smith RK
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2020: An idealized numerical study of tropical cyclogenesis and evolution at the Equator. Quart. J. Roy. Meteor. Soc. 146, 685-699
Kilroy G, Smith RK and Montgomery MT
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2020: Comments on: How much does the upward advection of supergradient component of boundary-layer wind contribute to tropical cyclone intensification and maximum intensity? J. Atmos. Sci. 77(12), 4377-4378
Smith RK, Kilroy G, and Montgomery MT
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2020: Contribution of mean and eddy momentum processes to tropical cyclone intensification. Quart. J. Roy. Meteor. Soc. 146, 3101-3117
Montgomery MT, Kilroy G, Smith RK, and Črnivec N
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2021: Evolution of Convective Characteristics During Tropical Cyclogenesis. Quart. J. Roy. Meteor. Soc. 147, 2103-2123
Kilroy G
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2021: Tropical cyclone life cycle in a threedimensional numerical simulation. Quart. J. Roy. Meteor. Soc. 147, 3373-3393
Smith RK, Kilroy G, and Montgomery MT
