Dust in the Wind: NASA Mars Global Surveyor Measures Dust Levels at MER Landing Sites

This graph made out of data from the thermal emission spectrometer onboard Mars Global Surveyor represents the atmospheric dust levels at the Mars landing sites in December 2003 and early January 2004. Measurements at Gusev Crater (red curve) and Meridiani Planum (black curve) suggest that a large regional dust storm beginning in mid-December raised significant dust near Meridiani. Smaller amounts of dust were spread globally by winds, the effects of which were seen at Gusev Crater. For comparison, an optical depth value of 1.0 corresponds to a very smoggy day in Los Angeles or Houston, and a value of 0.1 to a relatively clear day in Los Angeles.

Image credit: NASA/JPL/Arizona State University