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

Abstract

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 Météorologie 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 less than ∼ 40µm. By comparing the data of relative humidity, temperature and water vapor volume mixing ratio at two different heights (near-surface, ∼ 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 ∼ 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 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.

Cryogenic origin of fractionation between perchlorate and chloride under modern martian climate

“…The LMD GCM simulates water and dust transport, including the microphysics and radiative effects of water ice clouds, dust/ice sedimentation and condensation/ sublimation of water/ice at the surface [63][64][65][66][67] . The model has also been used to predict and analyze the night-time near-surface relative humidity on Mars 68 . The model is continuously confronted with available observations to validate its results.…”

A Mars bolygó kutatása • Studying Planet Mars

“…Egy marsi év leforgásának illusztrációja, rajta az északi félteke évszakainak jelentős fordulóival (ezekkel egy időben a déli féltekén ellentétes évszak van), valamint a napközel (perihélium), naptávol (aphélium) és a porviharos időszak megjelölésével. A marsi év előrehaladtát általában az ábrán is feltüntetett, szoláris hosszúságban (Ls°) mérik (Pál et al, 2019) szatér. A két félteke ily módon eltérő évszakait a Mars erősen elnyúlt, excentrikus pályájával (1. ábra), illetve a keringési sebesség ezzel járó változásaival lehet magyarázni -ugyanakkor a déli pólussapka nyáron is megmaradó szén-dioxid fedőrétege magas albedójának (fényvisszaverő képességének) kialakulása még pontosan nem tisztázott.…”

Insights into the Survival Capabilities of Cryomyces antarcticus Hydrated Colonies after Exposure to Fe Particle Radiation

“…(i) the low thermal inertia and temperature, which allow the increment of humidity level or by (ii) movements on the Martian surface [17].…”

“…It has been demonstrated that deliquescence in specific Martian regions could be provided by: the low thermal inertia and temperature, which allow the increment of humidity level or by movements on the Martian surface [ 17 ]. …”