Martian water ice clouds: A view from Mars Global Surveyor Thermal Emission Spectrometer

We have used the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) data to map water ice clouds in the Martian atmosphere in the latitude range -60 to +60 over a period of three Martian years. We have used the same method we have previously used on Viking Infrared Thermal Mapper data in order to allow direct comparison of the cloud behavior in the Viking and MGS eras and confirmed the validity of this method by comparing it to MGS TES standard retrievals. We note that the large-scale behavior of water ice clouds is remarkably consistent, both between the Viking and the MGS eras as well as between years observed by MGS. We also compare our results to water ice absorption-only optical depths derived from TES data and show that correlation is best for type 2 water ice clouds.