Extended Abstract (972K)8.5
The sensitivity of numerically simulated cyclic mesocyclogenesis to variations in environmental parameters
Edwin J. Adlerman, University of Oklahoma, Norman, OK; and K. K. Droegemeier
In a previous paper, we used a three-dimensional numerical model to study the evolution of cyclic mesocyclogenesis within a single supercell thunderstorm. As a follow-up to that study, we also examined the effect of variations in model physical and computational parameters upon the cycling process. Changes in grid spacing, numerical diffusion, microphysics, and the coefficient of surface friction were found to alter the number and duration of simulated mesocyclone cycles. With the additional understanding of the numerical model's influence upon cycling, we now seek to identify the environmental conditions necessary to produce cyclic redevelopment within a supercell updraft.
In this study, we present several preliminary simulations that highlight the role of the environment in the cycling process. Starting with an idealization of the 20 May 1977 Del City, Oklahoma hodograph that retains cyclic behavior, systematic variations of the environmental wind profile are examined. Changes in the shape of the hodograph are investigated, as well as variations in the magnitude and location of the shear. The impact of these changes will be examined for their influence on storm structure and subsequent alteration of cycling behavior.
Session 8, Numerical Modeling of Severe Storms
Wednesday, 14 August 2002, 8:00 AM-10:00 AM
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