Dust Storm Climatologies Derived from Mars Climate Sounder Measurements at Varying Observation Geometries

The Mars Climate Sounder (MCS) collects radiance measurements of the Martian atmosphere using remote sensing in several observational geometries (in-track and cross-track limb scanning, nadir sounding, and polar buckshot scanning). Temperature profiles and dust column optical depths retrieved from these radiance measurements can be used to study three annually occurring regional-scale Martian dust storms (A, B, and C). Regional-scale dust storms are defined with in-track, daytime data as events where the local temperature at a pressure level of 50 Pa exceeds 200 K or the dust column optical depth exceeds 0.1. However, due to changes in the performance of MCS in 2024, the instrument was modified to view solely in the right cross-track geometry rather than alternating between in-track and cross-track geometries. As a result, MCS now observes perpendicular to its orbit, meaning daytime measurements occur 1.5 hours later and nighttime measurements occur 1.5 hours earlier than in the in-track data. This change in observational geometry necessitates the definition of new, right cross-track temperature and optical depth criteria for regional-scale dust storms. Furthermore, this project aims to create new criteria to define the bounds of regional-scale dust storms for nighttime data.