On the optical studies of the atmospheric water vapour from the surface ofMars

Remote observations of the atmospheric water vapour from the Mars orbit wer e usually carried out to study its global distribution and variability. Mea surements of the water vapour abundance onboard the landers have recently b ecome an important complement to the orbital sounding, Narrow-band filter p hotometry and spectroscopy of the solar radiation from the surface of the p lanet proved to be a powerful tool in the study of atmospheric water. The I mager for Mars Pathfinder (IMP) was the first instrument to measure its amo unt from the surface, The Surface Stereo Imager (SSI) onboard the Mars Pola r Lander (MPL) was to follow but the spacecraft was lost at landing. Nevert heless significant expertise in the optical measurements of atmospheric H2O was gained during these missions. This paper summarizes this experience em phasizing the radiative transfer aspects of the problem. The results of thi s study could be of importance for future missions to Mars. (C) 2000 Elsevi er Science Ltd. All rights reserved.