MAVEN observes upper level Martian winds over the course of about two years.
MAVEN is the first spacecraft specifically designed to study the Mars upper atmosphere, in order to better understand the evolution of its climate. These visualizations show MAVEN measuring the Martian upper level wind direction and magnitude over a series of thirty-three campaigns. In order for MAVEN to make these in-situ measurements, the spacecraft must be close to the upper atmosphere. The closest point of MAVEN's orbit to Mars (periapsis) dips into the tenuous upper reaches of the Martian thermosphere. The orbit also precesses over time to acquire measurements from different regions on the planet.
Now, scientists have used MAVEN data to map high-altitude wind currents on Mars for the first time. The data show that the Martian upper atmosphere is relatively independent of the daily rotation of Mars. On a day-to-day basis, high-altitude wind currents have a relatively fixed location with respect to the Sun, while Mars rotates underneath. Over the course of the Martian year, however, the currents follow the Sun north to south with the seasons.
MAVEN has also found that higher-elevation regions, such as the Tharsis plateau, cause small gravity waves that perturb the upper level winds and make them alter course. This means that certain topographic features on the Martian surface are detectable by MAVEN high above, as it skims the edge of space.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 18.104.22.168.0