The Hot-Dry-Windy Index: A New Fire Weather Index

Atmosphere

JosephJ. Charney¹  AlanF. Srock²  BrianE. Potter³  ScottL. Goodrick⁴ 

[1] Hydrologic Sciences, St. Cloud State University, 720 4th Avenue South, St. Cloud, MN 56301, USA;;Department of Atmospheric &Northern Research Station, U.S. Forest Service, 3101 Technology Blvd., Suite F, Lansing, MI 48910, USA;Pacific Northwest Research Station, U.S. Forest Service, 400 N 34th Street, Suite 201, Seattle, WA 98103, USA;

关键词: fire weather;    index;    Haines Index;   

DOI  :  10.3390/atmos9070279

来源: DOAJ

【 摘 要 】

Fire weather indices are commonly used by fire weather forecasters to predict when weather conditions will make a wildland fire difficult to manage. Complex interactions at multiple scales between fire, fuels, topography, and weather make these predictions extremely difficult. We define a new fire weather index called the Hot-Dry-Windy Index (HDW). HDW uses the basic science of how the atmosphere can affect a fire to define the meteorological variables that can be predicted at synoptic-and meso-alpha-scales that govern the potential for the atmosphere to affect a fire. The new index is formulated to account for meteorological conditions both at the Earth’s surface and in a 500-m layer just above the surface. HDW is defined and then compared with the Haines Index (HI) for four historical fires. The Climate Forecast System Reanalysis (CFSR) is used to provide the meteorological data for calculating the indices. Our results indicate that HDW can identify days on which synoptic-and meso-alpha-scale weather processes can contribute to especially dangerous fire behavior. HDW is shown to perform better than the HI for each of the four historical fires. Additionally, since HDW is based on the meteorological variables that govern the potential for the atmosphere to affect a fire, it is possible to speculate on why HDW would be more or less effective based on the conditions that prevail in a given fire case. The HI, in contrast, does not have a physical basis, which makes speculation on why it works or does not work difficult because the mechanisms are not clear.

【 授权许可】

Unknown