loading page

Planet Four: Derived South Polar Martian Winds Interpreted Using Mesoscale Modeling
  • +3
  • Ganna Portyankina,
  • Klaus-Michael Aye,
  • Megan E Schwamb,
  • Candice J Hansen,
  • Timothy I Michaels,
  • Chris J Lintott
Ganna Portyankina
University of Colorado in Boulder

Corresponding Author:[email protected]

Author Profile
Klaus-Michael Aye
University of Colorado in Boulder
Author Profile
Megan E Schwamb
Queen's University Belfast
Author Profile
Candice J Hansen
Planetary Science Institute
Author Profile
Timothy I Michaels
SETI Institute
Author Profile
Chris J Lintott
University of Oxford
Author Profile


For the first time, model-derived and imagery-derived wind directions and speeds have been compared in Mars’ south polar region. Seasonal fan-shaped deposits are routinely observed by HiRISE in the polar regions. They are widely accepted to result from CO 2 gas jet eruptions. Fan lengths, sizes, and shapes can provide information about wind directions and strengths at the times such eruptions occur. We utilize a catalog of those fan-shaped deposits, marked by citizen scientists within the framework of the Planet Four (P4) project, at 27 regions of interest (ROIs) for two spring seasons (Mars Year 29 and 30). Fans change considerably from one HiRISE image to another at most of these ROIs as wind direction changes over the spring season. Leveraging this characteristic, intraseasonal variations in near-surface wind speeds and directions were retrieved and compared to near-surface winds predicted by a mesoscale atmospheric model (MRAMS) at the same ROIs. At most ROIs P4-inferred wind directions are consistent with those from MRAMS. The P4-derived wind speeds are less constrained, but are consistent with MRAMS wind speeds at the majority of ROIs. The overall consistency between the P4-inferred and MRAMS wind directions supports the underlying assumption that fan formation is controlled by the wind, and is not simply due to ballistic trajectories of material exiting suitably non-vertical vents. Measurements of seasonal fan-shaped deposits in HiRISE imagery can thus provide important intraseasonal information about near-surface winds-invaluable for both validating climate modeling and quantitatively investigating Mars polar processes.