Observations of Ultrafast Kelvin Wave Breaking in the Mars Thermosphere

TL;DR

This study presents the first observations of ultrafast Kelvin waves in Mars' thermosphere, revealing their vertical structure and wave breaking phenomena using MAVEN and MRO data.

Contribution

It provides the first altitude-dependent characterization of UFKWs on Mars, including evidence of wave breaking at around 170 km.

Findings

UFKWs observed at multiple altitudes up to 170 km

Wave energy dissipation indicative of wave breaking

Vertical propagation characteristics of UFKWs

Abstract

Ultrafast Kelvin Waves (UFKWs) have been recently discovered at Mars using measurements by the Mars Atmosphere and Evolution (MAVEN) Accelerometer (ACC) instrument and the Mars Reconnaissance Orbiter (MRO) Mars Climate Sound (MCS) instrument [1]. UFKWs are eastward propagating, have a 2-3 sol period with sufficiently long vertical wavelengths to propagate into the thermosphere, and are predicted by classical wave theory to be equatorially trapped. These prior measurements characterized UFKWs at two relatively narrow altitude bands, with one measurement altitude near 80 km and a second near 150 km. Thermospheric density profiles from solar occultation (SO) measurements made by the Extreme Ultraviolet Monitor (EUVM) onboard MAVEN [2] provide a means to characterize multi-sol period waves, including UFKWs, as a function of altitude. In this study, we present first-ever observations of UFKWs as a function of altitude, including observations of rapid wave energy dissipation near 170 km indicative of wave breaking.