Science Seminars

Wave Coupling in the Upper Atmospheres of Earth and Mars

Speaker: Federico Gasperini (Utah State University)
Date: Thursday, Feb 01, 2018
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

There is now convincing evidence that the structure and dynamics of the upper atmosphere of Mars is driven by a combination of solar and wave forcing effects, very similar to Earth. Atmospheric tides are the driving force of short-term temperature and wind changes throughout the planet’s atmosphere. In addition to tides, global-scale waves of longer periods are excited in the lower atmosphere and propagate upward before depositing their momentum and energy in the upper atmosphere when they dissipate. While in the last decade our understanding of the processes responsible for this coupling has considerably improved, largely driven by the deployment of new missions, there are many unresolved questions regarding the impacts of the entire spectrum of these waves on Mars’ upper atmosphere. In this work, we extend the techniques that we developed to diagnose waves in Earth’s thermosphere from TIMED-SABER and GOCE satellite data to investigate the effects of upward propagating waves on Mars’ middle and upper atmosphere. Using concurrent temperature and neutral density measurements taken by the MRO/MCS and MAVEN satellites during 1 November 2014 – 31 April 2017, we demonstrate that, similar to the dynamical signatures observed at Earth, a strong quasi-3 day ultra-fast Kelvin wave (UFKW) is a dominant global feature of the low-latitude thermosphere of Mars. We furthermore show that secondary waves generated by nonlinear interactions between the UFWK and solar tides add to the complexity of thermospheric dynamics at both planets.