Space Science Institute

The Dynamical Importance of Atmospheric Gravity Waves (GWS) at Mars Has Long Been Recognized. Modeling Suggests That Drag Due to GW Saturation Can Slow the Winter Westerly Jets in the Middle Atmosphere and Generate a Downwelling Circulation That Adiabatically Heats the Winter Polar Atmosphere Above Radiative Equilibrium a Phenomenon Particularly Notable in Dust Storms. the Temperature Fluctuations Generated by GWS Also Are Implicated in Creating Cold Pockets in the Middle Atmosphere in Which CO2 Can Condense and Form Clouds. in the Upper Atmosphere GWS Generate Large Density Fluctuations That Affect Aerobraking or Deep Dipping Spacecraft and Strongly Heat/cool the Thermosphere by Mechanical Dissipation. Mechanical Stirring by GWS Also Homogenizes Atmospheric Composition in the Upper Atmosphere Potentially Affecting Atmospheric Escape Rates. Better Understanding GWS at Mars Therefore Will Lead to Better Understanding of Applied Problems Such as Reliable Aerocapture at Mars as Well as Basic Scientific Questions Regarding the Dynamics and Evolution of Mars S Atmosphere. Modeling Has Been Quite Successful at Understanding the Potential Impact of GWS But It Has Proceeded With Few Observational Constraints on the Sources/activity of GWS in the Lower and Middle Atmosphere. Existing Constraints Mainly Come From Radio Occultations Which Are Sensitive to Gravity Waves With Wavelengths Greater Than a Few Hundred KM and Tend to Have Much Sparser Observational Patterns Than Mapping Instruments. However Potential Constraints With Higher Data Density and Different Sensitivities to GWS Exist (such as Small-scale Temperature Variances in On-planet Infrared Soundings) But Are Still Mostly Unexploited. This Proposal Uses Multiple Publicly Available Spacecraft Instrument Datasets From Mro MGS and Ody to Better Understand GW Activity at Mars (a Phenomenon of Wide Theoretical Interest in Atmospheric Dynamics and the Subject of Ongoing Modeling) and Thereby Enhance the Science Return From These Instruments. Modeling Will Be Primarily Focused on Understanding the Sensitivity of the Observations to GW Activity and So the Vast Majority of the Project's Activities Will Be Analysis of Radiance and Image Data. It Is Therefore Within the Scope of Mdap. the Pi Frequently Collaborates With the Mro-mcs Science Operations Team But Has No Formal Status on the Team and Currently Receives No Funding From Mro. Thus the Proposed Work Does Not Overlap With Work Supported Through the Mro Project.