Visibility and Line-of-Sight Extinction Estimates in Gale Crater During the 2018/MY34 Global Dust Storm

Abstract

Northern line-of-sight extinction within Gale Crater during the 2018 global dust storm was monitored daily using Mars Science Laboratory's Navcam. Additional observations with Mastcam (north) and Navcam (all directions) were obtained at a lower cadence. Using feature identification and georeferencing, extinction was estimated in all possible directions. Peak extinction of >1.1 km−1 was measured between sols 2086 and 2090, an order of magnitude higher than previous maxima. Northern and western directions show an initial decrease, followed by a secondary peak in extinction, not seen in column opacity measurements. Due to foreground topography, eastern direction results are provided only as limits, and southern results were indeterminable. Mastcam red and green filter results agree well, but blue filter results show higher extinctions, likely due to low signal-to-noise. Morning results are systematically higher than afternoon results, potentially indicative of atmospheric mixing.