Supercooled liquid water above Meridiani?

[exoscientist]

Posted to sci.astro:<br /><br />==================================================<br /><br />This page shows the air temperatures 100 meters above Meridiani:<br /><br />PIA07103: Seasonal Air Temperatures Above Opportunity <br />http://photojournal.jpl.nasa.gov/catalog/PIA07103<br /><br />The graph shows late afternoon air temperatures exceed -40 C even into the current Winter season at Meridiani. <br />Recent imaging at Meridiani also shows water condensing to ice on the surface which proves the presence of atmospheric water vapor there. <br />It is well known that liquid water can form in air at temperatures below 0 C. Even down to -40 C some proportion of condensed water will be in liquid form. Down to -20 C the majority of condensed water is in liquid form:<br /><br />Super-cooled Clouds (1 of 3) <br />"At temperatures below -20 degs. C, clouds consist mostly of ice particles, <br />while below -40 degs. C they are composed entirely of ice particles. <br />However, between 0 degs. C and -20 degs. C, a significant number of clouds may <br />be primarily composed of water droplets. Water droplets below 0 degs. C are <br />supercooled, and clouds containing large, supercooled droplets can pose <br />an extreme hazard to aviation. During day-time, 3.9 um imagery can be used to <br />infer droplet phase at cloud top because of differences in reflection between <br />ice particles and water droplets, as discussed earlier in the section on <br />emission and reflection. By using the 3.9 um imagery to <br />identify phase, and the 10.7 um imagery to determine cloud top temperature, <br />cloud tops consisting of supercooled water droplets may be located." <br />http://www.cira.colostate.edu/ramm/goes39/sprcool1.htm<br /><br />So the difference in reflectivity at these different infrared wavelengths <br />could help in distinguishing ice <div class="Discussion_UserSignature"> </div>