Experimental data on aerosols on Mars: VIKING, PHOBOS and future missions

Aerosols play an important role in the formation of the Martian climate, but their properties are not well studied. Atmospheric studies with the cameras of VIKING landers were an important step. Later a few instruments on board of the PHOBOS-2 spaceraft added new interesting messages about the vertical distribution, sizes of particles, optical depths and column abundancies of aerosols in some locations. Limb observations in the thermal infrared gave the first experimental estimation of the aerosols' vertical profile in the troposphere. This method and infrared solar occultation spectrometry could be successfully used to study aerosols in future missions from orbiting spacecrafts with many others. Small lidar type instruments in the landers' payload may be also very promising.