Cloudspotting on Mars: Mapping Mesospheric Clouds through Citizen Science

Mesospheric clouds on Mars are tracers of fundamental atmospheric processes, such as vertical and horizontal transport of water, thermal tides, and gravity waves. Observations of mesospheric clouds by several instruments have revealed distinct populations and confirmed the composition of individual clouds. However, differences in coverage have precluded a comprehensive understanding of their spatial-temporal distribution. Recent studies of mesospheric CO2-ice clouds have shown clear variations from day-to-night due to differences in thermal structure and dynamic phenomena. Questions remain about their microphysical properties and the sources of the gravity waves that enable their formation. High altitude water-ice clouds provide a means of probing the distribution of water in the middle atmosphere, which is important for better understanding the connection between lower atmospheric water and escape of hydrogen to space.

Limb measurements from the Mars Climate Sounder (MCS) provide a comprehensive dataset for mapping mesospheric clouds. Here, we present first results of the Cloudspotting on Mars Citizen Science project. This is a NASA-funded citizen-science project on the Zooniverse platform where participants identify clouds, which appear as arch-shaped features in MCS limb observations, by analyzing images representing time-series profiles of atmospheric radiance. Within two weeks of launching the project, over 100,000 classifications were completed spanning an entire Mars Year (MY29) and eight of MCS's spectral channels. We describe methods used to aggregate crowd-sourced cloud identifications and show preliminary results of major populations of mesospheric clouds. We compare the citizen-science curated catalog of clouds with the output of an automated algorithm and use the automated technique to extend the climatologies beyond MY29.