The impact of climate change on fire weather as predicted by a regional climate model

This study assesses the potential impact of climate change on fire risk and fire behavior based on the projected impact on fire weather in different parts of the United States. The main focus will be on the changes in the well-known fire weather index, the Haines Index (HI), which indicates the potential for fire danger by measuring atmospheric stability and dryness. The study will utilize results from a regional climate model (RCM) simulations conducted at the Eastern Area Modeling Consortium (EAMC) – a part of the regional Fire Consortia for Advanced Modeling of Meteorology and Smoke (FCAMMS) established by the U.S. National Fire Plan.

The EAMC RCM is based on the Fifth Generation Penn State University (PSU)/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5). All RCM simulations were driven by the NCAR Community Climate System Model version 3.0 (CCSM3) and were run at 36-km horizontal resolution over contiguous United States for current climate that covers 10-yr period of 1991-1999, and for future 10-yr climate in mid 21st century (2045-2054).

The HI was calculated based on the RCM simulated climate variables. The differences between the current and future HI values are examined to determine climate change impact on fire weather for different regions in the United States. An emphasis is placed on the changes in the location and frequency of occurrences of large HI value that indicates high potential for large and erratic plume-dominated wildfire. Uncertainties associated with this particular climate impact assessment are also discussed.