A cloud-resolving model is used to examine the intensification of tilted tropical cyclones from depression to hurricane strength over relatively cool and warm oceans under idealized conditions where environmental vertical wind shear has become minimal. Variation of the SST does not substantially change the time-averaged relationship between tilt and the radial length scale of the inner core, or between tilt and the azimuthal distribution of precipitation during the hurricane formation period (HFP). By contrast, for systems having similar structural parameters, the HFP lengthens superlinearly in association with a decline of the precipitation rate as the SST decreases from 30° to 26
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Tropical cyclones are commonly observed to have appreciable vertical misalignments prior to becoming full-strength hurricanes. The vertical misalignment (tilt) of a tropical cyclone is generally coupled to a pronounced asymmetry of inner-core convection, with the strongest convection tending to concentrate downtilt of the surface vortex center. Neither the mechanisms by which tilted tropical cyclones intensify nor the time scales over which such mechanisms operate are fully understood. The present study offers some insight into the asymmetric intensification process by examining the responses of tilted tropical cyclone–like vortices to downtilt diabatic forcing (heating) in a 3D nonhydrostatic numerical model. The magnitude of the heating is adjusted so as to vary the strength of the downtilt convection that it generates. A fairly consistent picture of intensification is found in various simulation groups that differ in their initial vortex configurations, environmental shear flows, and specific positionings of downtilt heating. The intensification mechanism generally depends on whether the low-level convergence
- Award ID(s):
- 2208205
- NSF-PAR ID:
- 10493624
- Publisher / Repository:
- American Meteorological Society
- Date Published:
- Journal Name:
- Journal of the Atmospheric Sciences
- Volume:
- 80
- Issue:
- 7
- ISSN:
- 0022-4928
- Page Range / eLocation ID:
- 1787 to 1814
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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