Global seasonal variations of the near-surface relative humidity levels on present-day Mars

Pal, Bernadett ✉ [Pál, Bernadett, szerző] Konkoly Thege Miklós Csillagászati Intézet (CSFK); Kereszturi, Akos [Kereszturi, Ákos (Planetológia, bol...), szerző] Konkoly Thege Miklós Csillagászati Intézet (CSFK); Forget, Francois; Smith, Michael D.

Angol nyelvű Tudományos Szakcikk (Folyóiratcikk)
Megjelent: ICARUS 0019-1035 1090-2643 333 pp. 481-495 2019
  • SJR Scopus - Astronomy and Astrophysics: Q1
We investigate the global seasonal variations of near-surface relative humidity and relevant attributes, like temperature and water vapor volume mixing ratio on Mars using calculations from modelled and measurement data. We focus on 2 AM local time snapshots to eliminate daily effects related to differences in insolation, and to be able to compare calculations based on modelling data from the Laboratoire de Meteorologie Dynamique Mars General Circulation Model with the observations of Mars Global Surveyor Thermal Emission Spectrometer. We study the seasonal effects by examining four specific dates in the Martian year, the northern spring equinox, summer solstice, autumn equinox, and winter solstice. We identify three specific zones, where the near-surface relative humidity levels are systematically higher than in their vicinity regardless of season. We find that these areas coincide with low thermal inertia features, which control surface temperatures on the planet, and are most likely covered with unconsolidated fine dust with grain sizes smaller than similar to 40 mu m. By comparing the data of relative humidity, temperature and water vapor volume mixing ratio at three different heights (near-surface, similar to 4 m and similar to 23 m above the surface), we demonstrate that the thermal inertia could play an important role in determining near-surface humidity levels. We also notice that during the night the water vapor levels drop at similar to 4 m above the surface. This, together with the temperature and thermal inertia values, shows that water vapor likely condenses in the near-surface atmosphere and on the ground during the night at the three aforementioned regions. This condensation may be in the form of brines, wettening of the fine grains by adsorption or deliquescence. This study specifies areas of interest on the surface of present day Mars for the proposed condensation, which may be examined by in-situ measurements in the future.
Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSLMásolásNyomtatás
2021-07-28 13:36