Planet Four: Probing Seasonal Winds on Mars by Mapping the Southern Polar CO2 Jet Deposits

South polar regions of Mars show extensive spring activity every year. The polar regions have been routinely monitored by HiRISE for the last 6 Martian years with the aim, among others, to understand how the surface and atmosphere are influencing each other. The seasonal activity in spring stems from differential sublimation of the seasonal CO2 ice layer and culminates in cold CO2 jets that erupt at multiple locations. The jets are known to modify the surface and interact with the atmosphere. They lift dust and sand particles into the lower atmosphere while near-surface winds transport the airborne particles, which fall back to the surface in fan-shaped deposits. We posted HiRISE observations in the Citizen Science Project Planet Four (http://www. planetfour. org) where volunteers were asked to mark seasonal fan deposits in the images presented to them. The reduction pipeline was implemented to create a catalog …