An assessment of Landsat TM band 6 thermal data for analysing land cover in tropical dry forest regions

Abstract

This research investigates the utility of integrating Landsat band 6 thermal data for land cover classification and, specifically, for the differentiation between successional stages of forest growth. Such successful differentiation has become critical for the assessment of land cover and land use change. The study area is in the state of Yucatan, Mexico, which is a region of predominantly tropical dry forest. Thermal band data measures the emission of energy from the Earth's surface and, as this is a function of the surface cover, it can be used as a determinant of land cover type based on the temperatures measured. This research uses a technique of land cover classification utilizing Landsat Thematic Mapper (TM) thermal band data. Land cover classes were found to relate strongly (an eta correlation ratio of 0.804) to band six calculated black body temperatures. Satellite coverages of black body temperatures also provided a unique spatial analysis of the image area using continuous data, not discrete classes. Discriminant analysis revealed that band 6 contains considerable information for the discrimination of land cover classes in the dry tropical forest ecosystem, with a coefficient of 0.354. Band 6 also outperformed many of the individual spectral bands of information, despite their greatly improved (×16) resolution.

Acknowledgments

This research was supported by the National Science Foundation (NSF) (SBR-9521918) as part of the ongoing research at the Center for the Study of Institutions, Population, and Environmental Change (CIPEC) at Indiana University. Fieldwork benefited from the invaluable research assistance of Julie Hanson. The author is very grateful to Dr J. C. Randolph, Dr Elinor Ostrom, Dr Otto Doering, Dr V. J. Meretsky and Michael Kohlhaas for their comments on earlier drafts; thanks Dr G. Green for many helpful discussions; and, finally, thanks Dr H. Nagendra for final comments and editing of the later versions of this manuscript.