Physics and Astronomy
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Browsing Physics and Astronomy by Author "Campbell, Charissa"
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Item Open Access Characterizing the Martian Environment Through Surface Spacecraft Observations(2024-07-18) Campbell, Charissa; Moores, JohnOver the course of a Mars Year (MY) atmospheric temperatures vary enough between the furthest (Aphelion) and closest (Perihelion) points in Mars' orbit due to an Earth-like obliquity and elliptical orbit, creating two distinct seasons. Aphelion has cooler temperatures and a cross-equatorial Hadley cell revealing equatorial water-ice clouds. Perihelion has warmer temperatures that support increased dust activity such as dust-devils or dust storms. These two seasons have been observed from orbit and surface, with surface vehicles crucially important for understanding surface-to-atmosphere interactions. Aerosols were examined for wind direction and speed using movies from the Mars Science Laboratory (MSL) rover and InSight lander due to their proximity. Similar Easterly wind directions during the Aphelion season for both landing sites helped pinpoint that observed aerosols were most likely aloft in the middle atmosphere, affected by the same large-scale circulation via Hadley cells. However, mission constraints such as power and data volume limit the amount of returnable data and the ability to fully understand these aerosols. Automated methods appear to show promising results based on an algorithm developed by a team from Curtin university and tested with known wind directions from MSL atmospheric movies. The Onboard Rover Cloud Algorithm (ORCA) could be used on future missions to significantly decrease data volume by simply returning a set of wind parameters without first downlinking images. To further expand low-cost options, an optical meteorological station was created based on the Phoenix Mars mission experiment that imaged the lidar beam shining within aerosols to calculate ice-water content. The Mars Atmospheric Panoramic camera and Laser Experiment (MAPLE) has a panoramic camera and multiple class 3R lasers to maximize returnable science in a minimal way. Field testing in dense fog in Newfoundland showed that MAPLE's lasers could detect fog decks up to 100 m above the camera during nighttime conditions. The lasers were unable to be resolved during the day, but a power calculation determined that all three lasers on MAPLE could be suitable for Martian polar conditions. Understanding the constraints of obtaining Martian atmospheric data enables low-cost options such as MAPLE to further our knowledge of these aerosols.Item Open Access Estimating the Altitudes of Clouds at the Mars Science Laboratory Landing Site(2019-03-05) Campbell, Charissa; Moores, JohnUsing the Navigation Camera, the Mars Science Laboratory (Curiosity) Rover images the atmosphere to capture clouds. A Zenith Movie (ZM) consists of eight upward-pointing images taken over five minutes. The angular distance and wind direction are measurable, but without a lidar the altitude is not. Instead, parameters are compared with results modelled by the Mars Regional Atmospheric Modelling System (MRAMS). An altitude is estimated with the half-normal probability distribution to evaluate the probability MRAMS has similar conditions to observational values. Throughout a sol, clouds were predicted below the crater rim and planetary boundary layer, but higher altitude clouds were primarily predicted in the morning. Results are compared to ice extinction data from the Mars Climate Sounder (MCS) and a shadow movement across Aeolis Mons through a Cloud Height Movie (CHM). Pairing a ZM with a CHM allows direct measurement of the altitude of clouds for the first time from the surface.