Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere: Difference between revisions
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Lichens, cyanobacteria and molds growing in humidity of simulated Martian atmosphere (edit)
Revision as of 02:55, 23 September 2018
, 5 years ago→Humidity observations of the Mars atmosphere by Curiosity
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[[Image:Curiosity humidity measurements.gif|thumb|Upper chart shows the humidity, lower chart shows the volume mixing ratio in parts per million, both measurements taken at the same time, height 1.6 meters above the ground]][[Image:Curiosity temperature measurements.gif|thumb|Upper chart shows the average temperature, lower chart shows the range, the warm orange and red colours are Curiosity annual readings, the blue and green dcolours are for the Viking landers and the gray colours are for the Phoenix lander]]
This section is based on the survey article by Martinez et al, "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity."<ref>Martínez, G. M., C. N. Newman, A. De Vicente-Retortillo, E. Fischer, N. O. Renno, M. I. Richardson, A. G. Fairén et al. [https://link.springer.com/article/10.1007/s11214-017-0360-x "The modern near-surface martian climate: A review of in-situ meteorological data from Viking to Curiosity."] Space Science Reviews 212, no. 1-2 (2017): 295-338.</ref>
The humidity variations on Mars are mainly due to the daily and seasonal variations of temperature of the air. Colder air has a higher relative humidity for the same water content.
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So, it's 10ppm (approx) for 70% RH in winter, and 70 ppm for 10% RH in summer (by a strange coincidence the numbers are reversed).
Curiosity has measured relative humidity readings of up to 70% in winter, measured at a height of 1.6 meters above ground level (see Sect 14<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Sec14 Sec 14]</ref>. This is in winter with a temperature range of around 50 C and mean temperature around -63 C, so lowest temperature around -88 C (see their figure 5<ref>[https://link.springer.com/article/10.1007/s11214-017-0360-x#Fig5 Fig5]</ref>), and the highest humidity is normally reached between 04:00 and 06:00 Local Mean Solar Time (LMST).. The lowest humidity readings are between 10:00 and 18:000 LMST, when they are typically less than 5%.
The Viking landers didn't have humidity sensors. But the humidity can be estimated indirectly, with maximum l volume mixing ratio of water vapour of 200 ppm for both spacecraft.
The Viking 2 observed frosts for 250 sols of the year (frost usually suggests a high relative humidity close to 100%).
Viking 1 and Curiosity didn't observe them directly. But there is indirect evidence that frosts may form at times at lower latitudes, including imaging of mists in the Valles Marineres, and possible observation of frost on deck and calibration target of Opportunity.
This article uses some text developed for Touch Mars?<ref>[http://robertinventor.com/booklets/If_humans_touch_Mars.htm#salt_pillar_oases Touch Mars? Salt pillar oases] - Touch Mars? by Robert Walker</ref>.
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