ISO LWS observations of Mars - Detection of rotational modulation in the far infrared

A series of far infrared (FIR) spectra of Mars between 43 and 196 mu m was taken with the Long Wavelength Spectrometer (LWS) on board the European Spa ce Agency's Infrared Space Observatory (ISO). Analysis of these medium-reso lution data reveals a rotational modulation of the disk-averaged FIR bright ness temperature. The observed variability of +/- 1.5% in the LWS wavelengt h range compares favorably with the predictions of a thermophysical model o f the martian surface. A surface emissivity of similar to 0.90 gives good a greement between the measured and the modeled brightness temperatures and l eads to an improved estimate of the LWS photometric calibration uncertainty , (C) 2000 Academic Press.