Analysis of thermal infrared data from the Digital Airborne Imaging Spectrometer

Thermal infrared data of the Digital Airborne Imaging Spectrometer ( DAIS), whose channels 74-79 are in the 8-13 mum waveband region, were analysed with the aim of recovering land surface temperature ( LST). DAIS images were acquired over an experimental site where field and laboratory emissivity measurements were performed, and these were used to recover the LST from the six DAIS thermal channels. Atmospheric correction of DAIS data was calculated by means of a nearby radiosounding and a radiative transfer model. DAIS derived LSTs were compared with ground measurements of LST made coincidentally for a few test fields, the central DAIS channels yielding temperatures up to 10 degreesC higher than ground measurements. A linear calibration was performed using in situ measurements of temperature and emissivity for two reference fields, and the large differences in temperature were then considerably reduced. Temperatures obtained from DAIS channel 79 agreed with the in situ measurements within +/-2 degreesC. This channel seemed the most reliable for deriving accurate LSTs in the dataset analysed here.