Extended Abstract (256K)P3.54
A Cloud Model Interpretation of the Enhanced V and Other Signatures atop Severe Thunderstorms
Pao K. Wang, Univ. of Wisconsin, Madison, WI; and H. M. Lin, S. Natali, S. Bachmeier, and R. Rabin
Satellite infrared images of some central US severe thunderstorms exhibit specific temperature features including an enhanced-V (or U), a closed-in warm spot, and a distant warm area. The previously suggested mechanisms responsible for these features include the cloud microphysical processes of ice crystal formation, entrainment of warm stratospheric air from above, radiative heating or cooling at the cloud top, and pure adiabatic thermodynamics. The present study uses a three-dimensional cloud model with complete liquid and ice microphysics to simulate the behavior of a US Midwest supercell storm and shows that the cloud top temperature features are produced by the combined effect of adiabatic dynamics, microphysics, heat transfer, and gravity wave processes. Each of these processes dominates a certain region on the cloud top. The simulated cloud top topography, defined as a layer of constant relative humidity surface, also exhibit some interesting features that have not been reported before. These features can be interpreted as due to the ship waves generated by the storm updraft core against upper level winds. This understanding may be used for satellite retrieval of winds near the tropopause level.
Poster Session 3, Operational Applications (Continued)
Tuesday, 16 October 2001, 2:15 PM-4:00 PM
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