Observations of ubiquitous nighttime temperature inversions in Mars' tropics after large-scale dust storms

TL;DR

This study reveals widespread nighttime temperature inversions in Mars' tropics during dust storms, linked to dust, topography, and atmospheric tides, affecting thermal structure and climate understanding.

Contribution

It provides the first comprehensive observation of temperature inversions in Mars' tropical atmosphere during dust storms and links them to dust, topography, and tides.

Findings

Inversions are strongest around Tharsis and Terra Sabaea.

Inversions correlate with dust storm strength.

Inversions are observed over plains, influenced by atmospheric tides.

Abstract

We report the ubiquitous occurrence of nighttime temperature inversions in the tropical martian atmosphere during the dusty season, as observed by the Mars Climate Sounder. The inversions are linked to the occurrence of large-scale regional dust storms, with their strengths largely correlated to the strengths of the dust storms. Inversions strengthen between 2 am and 4 am, with the bases of the inversions getting cooler, and the tops of the inversions getting warmer. The inversions are strongest around Tharsis and Terra Sabaea, which are higher-elevation regions, suggesting they are forming due to a combination of topographically-excited tides and cloud radiative cooling. However, inversions are also observed over the flat plains, and are likely associated with stronger tides resulting from the increased dust abundance. These results highlight an important interplay between the dust distribution, water ice clouds and thermal tides.