TY - JOUR AU - Pál, Bernadett AU - Kereszturi, Ákos AU - Forget, Francois AU - Smith, Michael D. TI - Global seasonal variations of the near-surface relative humidity levels on present-day Mars JF - ICARUS J2 - ICARUS VL - 333 PY - 2019 SP - 481 EP - 495 PG - 15 SN - 0019-1035 DO - 10.1016/j.icarus.2019.07.007 UR - https://m2.mtmt.hu/api/publication/30810334 ID - 30810334 N1 - Funding Agency and Grant Number: NKFIH [COOP - NN - 116927]; EXODRILTECH project [4000119270]; National Research, Development and Innovation Office (NKFIH, Hungary) [GINOP-2.3.2-15-2016-00003]; Origins and evolution of life on Earth and in the Universe COST actions [TD1308, 39045, 39078] Funding text: This work was funded by the COOP - NN - 116927 project of NKFIH, EXODRILTECH (4000119270) project, the GINOP-2.3.2-15-2016-00003 grant of the National Research, Development and Innovation Office (NKFIH, Hungary) and the TD1308 Origins and evolution of life on Earth and in the Universe COST actions numbers 39045 and 39078. Special thanks to Vladimir V. Zakharov for his invaluable help with the NetCDF file handling. The NetCDF files were visualized with the NASA GISS Panoply viewer developed by Dr. Robert B. Schmunk. The thermal inertia map (Fig. 6.) was created by Vilmos Steinmann. Special thank you for Gerard Willinger and Laszlo Szabados for the improvement of the language of the manuscript. We also thank the referees for their valuable input which have greatly improved this manuscript. AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Pál, Bernadett AU - Kereszturi, Ákos TI - Possibility of microscopic liquid water formation at landing sites on Mars and their observational potential JF - ICARUS J2 - ICARUS VL - 282 PY - 2017 SP - 84 EP - 92 PG - 9 SN - 0019-1035 DO - 10.1016/j.icarus.2016.09.006 UR - https://m2.mtmt.hu/api/publication/3117302 ID - 3117302 AB - Abstract Microscopic liquid brines, especially calcium-perchlorate could emerge by deliquescence on Mars during night time hours. Using climate model computations and orbital humidity observations, the ideal periods and their annual plus daily characteristics at various past, current and future landing sites were compared. Such results provide context for future analysis and targeting the related observations by the next missions for Mars. Based on the analysis, at most (but not all) past missions’ landing sites, microscopic brine could emerge during night time for different durations. Analysing the conditions at ExoMars rover’s primary landing site at Oxia Planum, the best annual period was found to be between Ls 115 - 225, and in L o c a l T i m e 2 - 5, after midnight. In an ideal case, 4 hours of continuous liquid phase can emerge there. Local conditions might cause values to differ from those estimated by the model. Thermal inertia could especially make such differences (low TI values favour fast cooling and H2O cold trapping at loose surfaces) and the concentration of calcium-perchlorate salt in the regolith also influences the process (it might occur preferentially at long-term exposed surfaces without recent loose dust coverage). These factors should be taken into account while targeting future liquid water observations on Mars. LA - English DB - MTMT ER - TY - JOUR AU - Kereszturi, Ákos AU - Möhlmann, D AU - Bérczi, Szaniszló AU - Gánti, T AU - Kuti, A AU - Sik, András AU - Horváth, András TI - Recent rheologic processes on dark polar dunes of Mars: Driven by interfacial water? JF - ICARUS J2 - ICARUS VL - 201 PY - 2009 IS - 2 SP - 492 EP - 503 PG - 12 SN - 0019-1035 DO - 10.1016/j.icarus.2009.01.014 UR - https://m2.mtmt.hu/api/publication/159237 ID - 159237 LA - English DB - MTMT ER -