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Center for Nonlinear Studies |
The dynamics of vortex axisymmetrization from the perspective of thermal perturbations is investigated using an idealized, nonlinear atmospheric model developed at LANL called HIGRAD. Attempts at reproducing the nonlinear modeling results of previous work (which used a different nonlinear model called WRF) revealed a discrepancy with the impacts of purely asymmetric forcing. The current study finds that linear, thermal asymmetries can have an important, largely positive role on the vortex intensification whereas prior work found nearly the opposite. Absolute angular momentum budgets reveal that the likely reason for the differences is the strength of the basic-state secondary circulation. Radial momentum budgets and sensitivity analysis further reveals that differences in effective diffusion between the two nonlinear models are likely the driving force behind these results. The goal of this work is to understand the dynamics of hurricane intensification. Recent measurements from advanced research radars developed at NASA Goddard Space Flight Center will be shown that provide motivation for the hurricane problem.
Host: Balu Nadiga, CCS-2, balu@beasley.lanl.gov, 667-9466