Three-dimensional structure of thermal waves in Venus' mesosphere from ground-based observations

TL;DR

This study uses high-resolution ground-based infrared observations to map Venus' mesosphere, revealing a planetary-scale thermal wave pattern consistent with a thermal tide propagating upward from the clouds.

Contribution

First three-dimensional temperature maps of Venus' mesosphere obtained from ground-based observations, showing thermal wave structures and their characteristics.

Findings

Thermal wave with zonal wavenumber 2--4 identified

Wave fronts tilt eastward with altitude at 8--15 degrees per km

Wave pattern strongest in Venus' mid-latitudes

Abstract

High spectral resolution observations of Venus were obtained with the TEXES instrument at NASA's Infrared Telescope Facility. These observations focus on a CO$_2$ absorption feature at 791.4 cm$^{-1}$ as the shape of this absorption feature can be used to retrieve the vertical temperature profile in Venus' mesosphere. By scan-mapping the planet, we are able to build up three-dimensional temperature maps of Venus' atmosphere, covering one Earth-facing hemisphere and an altitude range of 60--83 km. A temperature map from February 12, 2019 clearly shows the three-dimensional structure of a planetary-scale thermal wave. This wave pattern appears strongest in the mid-latitudes of Venus, has a zonal wavenumber of 2--4 and the wave fronts tilt eastward with altitude at an angle of 8--15 degrees per km. This is consistent with a thermal tide propagating upwards from Venus' upper cloud decks. Ground-based observations provide the opportunity to study Venus' temperature structure on an ongoing basis.