Thursday, 10 November 2016: 2:30 PM
Pavilion Ballroom East (Hilton Portland )
This study evaluates the main controls on the descent of the rear-inflow jet (RIJ), associated with a mesoscale convective system (MCS), toward the surface. This study employs the Cloud Model 1 (CM1), release 18.3, to simulate idealized MCSs. The model has a horizontal grid spacing of 1 km with 80 vertical levels, and utilizes doubly periodic lateral boundary conditions. The Morrison double-moment explicit moisture scheme is used and Coriolis accelerations are ignored. To initiate convection, forced convergence is applied over a limited subset of the domain for one hour. Simulations in which characteristics of the input sounding are perturbed are then considered to examine how the descent of the RIJ is impacted. This presentation will discuss findings pertaining to controls on the descent of the RIJ using perturbation analysis on the modeled MCSs. Emphasis will be given to comparing the results found herein to those by Weisman (1992) and hypotheses drawn from within for RIJ descent, particularly as it relates to the balance of the positive buoyancy-driven circulation associated with the ascending front-to-rear flow and the negative buoyancy-driven circulation associated with the cold pool within the MCS.
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