Multiscale Modeling Framework using Element-based Galerkin Methods for Moist Atmospheric Limited-Area Simulations

TL;DR

This paper introduces a multiscale modeling framework that couples large-scale and local atmospheric processes using element-based Galerkin methods, improving cloud process representation in limited-area weather simulations.

Contribution

It develops a coupled multiscale framework with a shared dynamical core and high-order discretization, enabling flexible resolution adjustment for atmospheric modeling.

Findings

Enhanced cloud process representation in simulations.

Successful application to 2D and 3D idealized storm problems.

Improved accuracy over coarse models.

Abstract

This paper presents a multiscale modeling framework (MMF) to model moist atmospheric limited-area weather. The MMF resolves large-scale convection using a coarse grid while simultaneously resolving local features through numerous fine local grids and coupling them seamlessly. Both large- and small-scale processes are modeled using the compressible Navier-Stokes equations within the Nonhydrostatic Unified Model of the Atmosphere (NUMA), and they are discretized using a continuous element-based Galerkin method (spectral elements) with high-order basis functions. Consequently, the large-scale and small-scale models share the same dynamical core but have the flexibility to be adjusted individually. The proposed MMF method is tested in 2D and 3D idealized limited-area weather problems involving storm clouds produced by squall line and supercell simulations. The MMF numerical results showed enhanced representation of cloud processes compared to the coarse model.