  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.
