Evaluation of novel thermally enhanced spectral indices for mapping fire perimeters and comparisons with fire atlas data

Abstract

We evaluated the potential of two novel thermally enhanced Landsat Thematic Mapper (TM)‐derived spectral indices for discriminating burned areas and for producing fire perimeter data (as a potential surrogate to digital fire atlas data) within two wildland fires (1985 and 1993) in ponderosa pine (Pinus ponderosa) forests of the Gila Wilderness, New Mexico, USA. Image‐derived perimeters (manually produced and classified from an index image) were compared to fire perimeters recorded within a digitized fire atlas. For each fire, the highest spectral separability was achieved using the newly proposed Normalized Burn Ratio‐Thermal (NBRT₁) index (M = 1.18, 1.76, for the two fires respectively). Correspondence between fire atlas and manually digitized fire perimeters was high. Landsat imagery may be a useful supplement to existing historical fire perimeters mapping methods, but the timing of the post‐fire image will strongly influence the separability of burned and unburned areas.

Acknowledgments

This research was supported in part by funds provided by the Rocky Mountain Research Station, Forest Service, US Department of Agriculture. The Upper Midwest Aerospace Consortium provided additional support. Thanks to the Gloria Barron Wilderness Society Scholarship and The Wilderness Society provided additional funding. We also thank Andrew Hudak and Lee Vierling for their early review of this manuscript.