Responses of dust loading on ozone, winds and heating rates in the southern hemisphere of Mars' atmosphere: Climatology and SPICAM observations
Abstract
We have used SPICAM observations for four Martian Years (MY27-MY30) to study the seasonal variability of column abundances of ozone and dust opacity at low latitudes (10$ ^{o}$-30$ ^{o}$N, 10$ ^{o}$-30$ ^{o}$S), mid-latitudes (30$ ^{o}$-50$ ^{o}$N, 30$ ^{o}$-50$ ^{o}$S) and high latitudes (50$ ^{o}$-70$ ^{o}$N, 50$ ^{o}$-70$ ^{o}$S). In these observations, year-to year seasonal variability of column ozone at the latitude of ~ 25$ ^{o}$S were nearly the same except in MY28 at Ls~280$ ^{o}$-310$ ^{o}$ when a global dust storm occurred. The altitude profiles of ozone heating rates are calculated in presence of dust storm at latitudes 2$ ^{o}$N-S, 25$ ^{o}$N-S, 45$ ^{o}$N-S and 70$ ^{o}$N-S for Ls~7.5$ ^{o}$, 47.5$ ^{o}$, 87.5$ ^{o}$, 127.5$ ^{o}$, 167.5$ ^{o}$, 207.5$ ^{o}$, 247.5$ ^{o}$, 287.5$ ^{o}$ and 327.5$ ^{o}$. At low and mid-latitudes the ozone heating rates increased until Ls~47.5$ ^{o}$. Afterwards it decreased until Ls~ 127.5$ ^{o}$ and then disappeared between Ls~ 167.5$ ^{o}$ and 327.5$ ^{o}$. In the presence of dust storm ozone heating rates increased by a factor of 2.5-3 up to 10 km at Ls~280$ ^{o}$. We have also used MCD datasets (https://hal.archives-ouvertes.fr/hal-01139592) to study the seasonal variability of zonal, meridional and vertical winds in the tropical atmosphere of Mars during MY28 and MY29. It is found that the density of ozone, wind speeds and ozone heating rates were severely affected by the global dust storm at latitude ~25$ ^{o}$S and Ls ~ 280$ ^{o}$.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.383H