A SCAN-ANGLE CORRECTION FOR THERMAL INFRARED MULTISPECTRAL DATA USINGSIDE LAPPING IMAGES

Thermal infrared multispectral scanner (TIMS) images, acquired with si de lapping flight lines, provide dual angle observations of the same a rea on the ground and can thus be used to estimate variations in the a tmospheric transmission with scan angle. The method was tested using T IMS aircraft data for six flight lines with about 30% sidelap for an a rea within Joshua Tree National Park, California. Generally the result s correspond to predictions for the transmission scan-angle coefficien t based on a standard atmospheric model although some differences were observed at the longer wavelength channels. A change was detected for the last pair of lines that may indicate either spatial or temporal a tmospheric variation. The results demonstrate that the method provides information for correcting regional survey data (requiring multiple a djacent flight lines) that can be important in detecting subtle change s in lithology.