Mapping Pre‐Fire Forest Conditions with NOAA‐AVHRR Images in Northern Boreal Forests

Abstract

In Canada, fire danger maps, predicted by the Canadian Fire Weather Index system, produced from weather station records, are limited spatially. Thus, remote sensing as a potential fire danger mapping tool was investigated. NOAA‐AVHRR images were used to map pre‐fire conditions over Canadian northern boreal forests. Daily mean surface and air temperature, normalized difference vegetation index and fire weather index values were analysed for burned and unburned areas. Prior to fire ignitions, it was hypothesized that mean surface temperature will: (i) increase with approaching ignition dates; (ii) be greater in burned than unburned areas; and (iii) be positively related to the fire weather index. Despite cloud contaminated images, a positive trend in mean burned area surface temperature was observed as ignition dates approached. This was not the case for mean air temperature. Similar trends were observed over unburned areas. A good relationship was found between surface temperature and the fire weather index, explained partly because both variables are related to air temperature.