Towards Coupled Fire-Atmosphere Modeling with the Unified Forecast System

Wildfires have significant socio-economic impacts, affecting the environment, damaging structures, endangering lives, compromising public health, and incurring high suppression costs. To address these impacts, accurate fire spread prediction models and fire behavior analyses are crucial for assisting decision makers. Coupled fire-atmosphere models provide a balance between realism and computational efficiency, rendering them suitable for both fire research and real-time operations. These models integrate numerical weather prediction (NWP) with fire behavior modeling, enabling the representation of complex fire-atmosphere interactions.

For instance, the community Weather Research and Forecasting (WRF) model has been extended with a fire behavior model, known as WRF-Fire. This advanced coupled atmosphere-wildland fire model stands at the forefront of fire research and forecast. Expanding this capability to other community models like the Unified Forecast System (UFS) will substantially enrich community resources for research and operational needs. With this objective in mind, we are currently integrating this fire behavior model into the UFS.

In our approach, we implemented a standalone fire behavior model, which interfaces with the UFS-Atmosphere using the interoperability software, the National Unified Operational Prediction Capability (NUOPC), developed by the Earth System Modeling Framework (ESMF). At the time of writing, simulations of fires with atmospheric forcing are possible, and there is a noteworthy consistency between the UFS simulations and the results of the one way coupled WRF-Fire. Efforts are underway to extend this into two-way coupling to be able to simulate fire-atmosphere interactions. The fire behavior model will be available to the community with continuous integration testing.

This presentation will offer an overview of our ongoing endeavors to enhance the UFS community resources with a fire behavior model, aiming to contribute to the mitigation of the extensive impacts associated with wildland fires.