Angle dependence of radiances in the ozone-sensing channel of the HIRS

The results of implementation of the LOWTRAN algorithm, intended for correction of the angle dependence of radiances in the ozone-sensing channel 9 (9.6 microns) of the high-resolution IR radiation sounder (HIRS), are presented. It is found that application of LOWTRAN caused considerable improvements in the magnitudes of the calculated radiances; at a zenith angle of 49 deg, for instance, the LOWTRAN produced a value almost coincident with in situ observations, whereas the original HIRS value of the limb darkening was 2.2 C less. It is inferred from the analysis that the values of empirically derived parameters are not transferrable from one satellite instrument to another.