Atmospheric correction of TIMS data

The Thermal Infrared Multispectral Scanner (TIMS) is a unique sensor for two reasons, it is multispectral in the thermal-infrared and it has on board, active calibration sources. The existence of the calibration permits the recorded DNs to be converted unambiguously to absolute energy units. However, to relate the data to energy originating from a target on the ground it is necessary to remove the atmospheric contribution to the signal, specifically its transmittance and emittance. These can be obtained fairly easily by use of the atmospheric model provided by LOWTRAN-6 and the data from the U.S. Weather Service network of bidaily radiosondes. Using these data with the TIMS responsivity curves an equation can be obtained which permits the unambiguous correction of the TIMS data for the atmosphere.