Assessing the Impact of Post‐Fire Land‐Surface Changes on Weather Forecasting in Two Forested Areas

Abstract

Wildfires have extensively burned areas worldwide, with significant impacts in various aspects of life. Among these, wildfires affect land-surface properties, such as vegetation nature and soil characteristics, from active burning to years and decades afterward. Despite this, the qualitative effects of post-wildfire conditions on short-term weather forecasting remain obscure. In this study, we investigated the impact of post-wildfire conditions on weather forecasting by considering post-wildfire land-surface conditions using the Weather Research and Forecasting (WRF) model in two burned forest areas. The changes in land-surface properties caused by wildfires were considered, including vegetation fraction, leaf area index, roughness length, emissivity, and soil hydraulic conductivity. The results show that post-wildfire land-surface properties have noticeable impacts on near-surface variables and atmospheric profiles. Over the study areas, the simulated near-surface air temperature could be approximately 1 K cooler and 0.75 g/kg moister if post-wildfire conditions are ignored, with impacts extending more than 3 km high in the vertical direction. This study also demonstrates that the effects of changes in land-surface properties over burned areas could extend to surrounding unburned areas.