Simple finite elements and multigrid for efficient mass-consistent wind downscaling in a coupled fire-atmosphere model

TL;DR

This paper introduces a finite element and multigrid method for efficient, mass-consistent wind downscaling in fire-atmosphere models, improving computational speed and accuracy.

Contribution

It presents a novel finite element formulation combined with a multigrid solver for mass-consistent wind downscaling in coupled fire-atmosphere simulations.

Findings

Maintains convergence across various grid resolutions and penalty coefficients.

Reduces computational cost of wind downscaling in fire modeling.

Enhances accuracy of air flow diagnostics over complex terrain.

Abstract

We present a simple finite element formulation of mass-consistent approximation, and a fast multigrid iterative method with adaptive semicoarsening, which maintains the convergence of the iterations over a range of grids and penalty coefficients. The method is designed to run in each time step of WRF-SFIRE and replace the interpolation from the atmospheric mesh to the fire mesh by a diagnostic model of the air flow over a fine-scale terrain.