Detections of Water Vapor Increase Over the North Polar Troughs on Mars as Observed by CRISM

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter has been observing the north polar layered deposits (NPLD) of Mars. Polar wind circulations are instrumental in shaping the NPLD. In particular, the downslope (katabatic) flows help carve the spiral-shaped geological depressions, known as the polar troughs, and appropriate environmental conditions develop katabatic jumps that favor substantial water abundance changes over the troughs. Utilizing CRISM retrievals, we report the first observational evidence of the sharp increase in the water vapor abundance over polar troughs on Mars at high resolution (similar to 320 m). This has a direct influence on the dynamic evolution of ice migration in the northern polar cap, the major source of atmospheric water on Mars.