The Line-Of-Sight Extinction Record At Gale Crater As Observed By Msl'S Mastcam And Navcam Through Similar To 2,500 Sols

The Mars Science Laboratory rover (Curiosity) has monitored the line-of-sight extinction within Gale Crater since mission sol 100 (16 November 2012, MY 31 L-s 208 degrees) with Navcam and since mission sol 1,187 (8 December 2015, MY 33 L-s 79 degrees) with the color imager, Mastcam. This work reports 1,375 sols (>2 MYs) of line-of-sight extinction monitoring within Gale Crater with Mastcam and updates the Navcam line-of-sight extinction record to sol 2,556 (15 October 2019, MY 35 L-s 93 degrees). A cyclical pattern with one or more peaks in the dusty season (L-s similar to 180-360 degrees) and a trough in the less-dusty season (L-s similar to 0-180 degrees) was observed with both imagers and the results from Mastcam red and Navcam agree well. Green and blue filter Mastcam data show generally lower extinction than in the red filter data. Extinction as a function of azimuth and elevation angle were investigated and the extinction as a function of azimuth was generally found to be smooth and thus the dust well-mixed horizontally. The extinction as a function of elevation shows increased dust loading at lower elevations during dusty seasons, indicative of dust lifting from the base of the crater.