Mapping land surface emissivity using AVHRR data application to La Mancha, Spain

Abstract

Land surface temperature can be determined applying the split‐window technique to the AVHRR channels 4 and 5. However, for this purpose the knowledge of land surface emissivities in the AVHRR channels 4 and 5 is essential. The paper proposes a simple method for mapping the difference between channels 4 and 5 surface emissivities (?? = ?₄ ‐ ?₅) at the AVHRR spatial scale. The method is based on the availability of radiosounding data coincident to the NOAA overpass for the study area and on the knowledge of the mean value of the land surface emissivity for channels 4 and 5 (? = (?₄ + ?₅)/2). Therefore, two simple methods for measuring and mapping the mean value of emissivity are also proposed, which use a reference calibrated sand and the normalized difference vegetation index (NDVI), respectively. And finally, a complete example of application of the methodology developed on the La Mancha region, Spain, is shown.