. .  , 2003, . 24, . 6, 1219–1236 Evaluating the performance of multitemporal image compositing algorithms for burned area analysis A. M. O. SOUSA Department of Rural Engineering, Universidade de E ´ vora, Apartado 94, 7000 E ´ vora, Portugal. Tel: 00351 266 7409823/00, Fax: 00351 266 711189, email: asousa@uevora.pt J. M. C. PEREIRA* and J. M. N. SILVA Department of Forestry, Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisboa, Portugal; email: jmcpereira@isa.utl.pt joaosilva@isa.utlpt (Received 20 March 2000; in final form 25 June 2001 ) Abstract. The main objective of this study was to compare the adequacy of various multitemporal image compositing algorithms to produce composite images suitable for burned area analysis. Satellite imagery from the NOAA Advanced Very High Resolution Radiometer (AVHRR) from three different regions (Portugal, central Africa, and South America) were used to compare six algorithms, two of which involve the sequential application of two criteria. Performance of the algorithms was assessed with the Jeffries-Matusita distance, to quantify spectral separability of the burned and unburned classes in the composite images. The ability of the algorithms to avoid the retention of cloud shadows was assessed visually with red-green-blue colour composites, and the level of radiometric speckle in the composite images was quantified with the Moran’s I spatial autocorrelation statistic. The commonly used NDVI maximum value compositing procedure was found to be the least appropriate to produce composites to be used for burned area mapping, from all standpoints. The best spectral separability is provided by the minimum channel 2 (m2) compositing approach which has, however, the drawback of retaining cloud shadows. A two- criterion approach which complements m2 with maximization of brightness temperature in a subset of the data (m2M4) is considered the better method. 1. Introduction 1.1. Objectives Biomass burning was identified as a significant factor in global greenhouse gas emissions over 20 years ago (Seiler and Crutzen 1980). More recently, it has been acknowledged that biomass burning represents a major perturbation of global atmo- spheric chemistry, comparable to that of fossil fuel burning (Andreae 1991, Levine 1991, Cicerone 1994). These findings have stimulated interest in the use of remotely sensed data to estimate accurately the global extent of areas burned annually. Some of the major analyses of burned areas using satellite imagery relied on multitemporal *Author for correspondence International Journal of Remote Sensing ISSN 0143-1161 print/ISSN 1366-5901 online © 2003 Taylor & Francis Ltd http://www.tandf.co.uk/journals DOI: 10.1080/01431160110114466