Geometric Properties of Water-ice Clouds as Observed from Jezero Crater in the First 600 sols with the NavCam Instrument On Board the Mars2020 Rover, Perseverance

Abstract

In the first 600 sols of the Mars2020 mission, LS 5.6o – 316.8o, 46 cloud movies and 145 cloud surveys were collected to observe clouds at Jezero Crater, the landing site of the Perseverance Rover. Cloud movies were processed using the Mean-Frame Subtraction (MFS) method for revealing cloud structures, which were subsequently analyzed using digital-image processing. Two-dimensional Fast Fourier Transforms (2D-FFT) were used to compute cloud structure sizes ranging from 2.90 to 15.25 km for clouds between 30 and 50 km altitude, based on coincident Mars Climate Sounder vertical profiles of atmospheric water-ice. Same-value thresholding was used to detect the cloud structures in MFS-processed and projected cloud movies. The resolution dependence that was needed to resolve these structures over various thresholds was examined to find multifractal scaling of Mars clouds for resolutions between 0.1 and 1.6 km. We characterize the multiscaling observed in the images and its implications for the design of cloud-tracking cameras from the surface as well as for cloud-resolving models.

Five Mars Years of Cloud Observations at Gale Crater: Opacities, Variability, and Ice Crystal Habits

“…There is substantial evidence suggesting that Martian cloud formation is driven at least in part by thermal tides (e.g., Hinson & Wilson 2004;Szantai et al 2021), implying that we would expect to observe diurnal changes in opacity. Indeed, diurnal variability in Martian aerosols has been previously documented, e.g., over Tharsis (Madeleine et al 2012) and Jezero (Patel et al 2023;Smith et al 2023). The most frequently observed pattern is an enhancement in the early morning, attributed to fogs that form overnight, and a smaller enhancement in the early afternoon, potentially due to increased dust lifting activity delivering more cloud condensation nuclei to cloud-forming elevations (Tamppari et al 2003).…”

One Martian Year of Near‐Surface Temperatures at Jezero From MEDA Measurements on Mars2020/Perseverance

“…At L S 153°, a regional dust storm passed across Jezero, with this location being an active dust lifting location (Lemmon et al, 2022), while at L S ∼213°and ∼313°, the large A and C yearly storms (Kass et al, 2016) reached Jezero, respectively. In turn, clouds produced the greatest increase in the measured atmospheric opacity around L S ∼145°, during the Aphelion Cloud Belt season (Patel et al, 2023;Smith et al, 2023;Toledo et al, 2023). This increase in atmospheric opacity was accompanied by an apparent increase in daily mean air temperatures (Figure 4a).…”