Using the Chombo Adaptive Mesh Refinement Model in Shallow Water Mode to Simulate Interactions of Tropical Cyclone-like Vortices

Abstract:

Complex multi-scale atmospheric phenomena such as tropical cyclones challenge the coarse uniform grids of convectional climate models. Adaptive mesh refinement (AMR) techniques seek to mitigate these problems by providing sufficiently high-resolution grid patches only over features of interests while limiting the computational burden of requiring such resolutions globally. One such model is the non-hydrostatic, finite-volume Chombo-AMR general circulation model (GCM), which implements refinement in both space and time on a cubed-sphere grid. The 2D shallow-water equations exhibit many of the complexities of 3D GCM dynamical cores and serve as an effective method for testing the dynamical core and the refinement strategies of adaptive atmospheric models. We implement a shallow-water test case consisting of a pair of interacting tropical cyclone-like vortices. Small changes in the initial conditions can lead to a variety of interactions that develop fine-scale spiral band structures and large-scale wave trains. We investigate the accuracy and efficiency of AMR’s ability to capture and effectively follow the evolution of the vortices in time. These simulations serve to test the effectiveness of refinement for both static and dynamic grid configurations as well as the sensitivity of the model results to the refinement criteria.