Addressing the Efficacy of the Base-State Substitution Idealized Modeling Technique: A Comparison of Simulations

Base-state substitution (otherwise known as BSS) is a recently developed idealized modeling technique that approximates environmental heterogeneity by replacing portions or the entirety of the horizontally homogeneous base-state at a user-defined interval. The updated environment embodies both spatial and temporal changes to the environment. This approach allows the user to independently modify different aspects of the environmental profiles without altering the structure of the storm-generated perturbation fields.

While the technique has been tested to ensure that it does not produce spurious or unphysical results, its efficacy in approximating heterogeneity has yet to be evaluated in comparison to model simulations that explicitly incorporate temporal and spatial environmental variability. BSS neglects the instantaneous effects of local environmental gradients, and it is unclear whether this omission will prevent realistic storm evolution and depiction of dynamical processes. To address this gap, a series of case study simulations were conducted whereby a given storm was simulated in a fully heterogeneous environment (using WRF), and in an approximately heterogeneous environment (using BSS in CM1). The results of each simulation pair will be shown, as well as comparisons of storm mode, track, and a variety of storm intensity metrics.