Mesospheric vertical thermal structure and winds on Venus from HHSMT CO spectral-line observations

TL;DR

This study uses spectral-line observations from the HHSMT to analyze the vertical thermal structure and wind velocities in Venus's mesosphere, revealing temperature variations and circulation patterns.

Contribution

It provides new ground-based measurements of Venus's mesosphere, cross-calibrates with space data, and enhances understanding of atmospheric circulation.

Findings

Detected day-to-day temperature variations

Observed short-term mesospheric zonal flow fluctuations

Confirmed warm air layer at 90-100 km altitude

Abstract

We report vertical thermal structure and wind velocities in the Venusian mesosphere retrieved from carbon monoxide (12CO J=2-1 and 13CO J=2-1) spectral line observations obtained with the Heinrich Hertz Submillimeter Telescope (HHSMT). We observed the mesosphere of Venus from two days after the second Messenger flyby of Venus (on June 5 2007 at 23:10 UTC) during five days. Day-to-day and day-to-night temperature variations and short-term fluctuations of the mesospheric zonal flow were evident in our data. The extensive layer of warm air detected recently by SPICAV at 90 - to 100 km altitude is also detected in the temperature profiles reported here. These data were part of a coordinated ground-based Venus observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to contribute to a more thorough understanding of the global patterns of circulation of the Venusian atmosphere.