Presentation #213.04 in the session Mars Atmosphere (iPosters).
The Aphelion Cloud Belt (ACB) seasons occurs from solar longitude (Ls) 45°-150° when atmospheric temperatures are cooler. These clouds are visible at two times of sol, morning and afternoon, and have been observed by the Mars Science Laboratory (MSL, Curiosity) since landing in Gale crater in August 2012. By making movies of these clouds, various meteorological parameters such as wind direction and opacity can be calculated. One parameter, altitude, is difficult to determine without an onboard lidar which Curiosity isn’t equipped with. However, it has been shown that by concurrently observing clouds above the rover and their shadows moving across Aeolis Mons (Mt Sharp) that the altitude can be directly calculated by correlating the observed angular and absolute wind speeds. Known as the Cloud Altitude Observation (CAO) it pairs two eight-frame movies, one that observes directly above the rover and the other at Aeolis Mons. To date, this observation has now collected data for three Mars Years (MYs).
Our presentation will show results from all three MYs. Data will be compared to detect any seasonal or interannual changes. For instance, higher altitudes are seen at the start and end of the cloudy season which could be indicative of carbon dioxide clouds. Wind properties such as meteorological wind direction will also be investigated to determine if there are any patterns associated with altitude. Unfortunately, the easterly pointing of the Aeolis Mons movie is not sun-safe in the morning, inhibiting the CAO from being done in the morning so no diurnal changes can be observed.