Humidity observations and column simulations for a warm period at the Mars Phoenix lander site : Constraining the adsorptive properties of regolith
| Autor: | E. Fischer, Nilton O. Renno, Aaron P. Zent, Ari-Matti Harri, Hannu Savijärvi, L. K. Tamppari, German Martinez |
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| Přispěvatelé: | Institute for Atmospheric and Earth System Research (INAR) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Ground frost
010504 meteorology & atmospheric sciences Mars CURIOSITY Atmospheric sciences 01 natural sciences 0103 physical sciences surface H2O Relative humidity WATER CYCLE meteorology EXCHANGE 010303 astronomy & astrophysics climate 0105 earth and related environmental sciences Morning Moisture ICE Humidity Astronomy and Astrophysics Mars Exploration Program 115 Astronomy Space science Regolith TRANSPORT 13. Climate action Space and Planetary Science Environmental science Water vapor |
| Popis: | Two recalibrated sets of Phoenix (PHX) near-surface TECP air humidity measurements were compared with results from adsorptive single column model simulations during a warm clear-sky polar midsummer period, PHX sols 50-60. The model's 2 m temperatures were close to the observed values. Relative humidity (RH) is very low during the day but at night RH at 2 m reaches nearly 100% by the Zent et al. (2016) recalibration (Z), and 60-70% by the Fischer et al. (2019) recalibration (F). Model values of RH2m are close to Z and F at night and to F during the day. All three imply low water vapor pressures near the surface at night, 0.03-0.05 Pa, with a rapid increase each morning to 0.3-1 Pa and a decrease in the evening by both F and the model simulation. The model's daily adsorbed and desorbed water is in balance for regolith porosity of 16% (instead of 35% for lower latitudes). The depleted layer of nighttime air moisture extends to only about 200 m above the surface; hence the model's precipitable water content stays around the observed similar to 30 mu m throughout the sol. The model's moisture cycle is not sensitive to tortuosity of the regolith but the in-pore molecular diffusivity should be at least 5 cm(2)/s for fair agreement with the observations. In the adsorption experiments there is no fog and just a hint of ground frost, as observed during this period. Strong night frosts appear if adsorption is made weak or absent in the model. |
| Databáze: | OpenAIRE |
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