[meteorite-list] Phoenix Observes Ice and Fog Near Surface on Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 24 Mar 2011 15:12:47 -0700 (PDT)
Message-ID: <201103242212.p2OMClPV018843_at_zagami.jpl.nasa.gov>

http://www.eurekalert.org/pub_releases/2011-03/agu-hia031711.php

Public release date: 17-Mar-2011

Contact: Kathleen O'Neil
koneil at agu.org
202-777-7524
American Geophysical Union


AGU journal highlights -- March 17, 2011

[snip]

2. Martian weather report: ice and fog near surface

A pair of cameras mounted on the back of the Phoenix Mars Lander
captured how laser light, emitted by the Lander's light detection and
ranging (lidar) system, was scattered by water ice in the red planet's
thin atmosphere. Moores et al. used the technique over four nights in
2008 to give the first detailed profile of the ice water content in the
Martian near-surface atmosphere.

The authors find that the icy fog was thickest around 50 meters (164
feet) above the surface, with maximum concentration of 1.7 milligrams
per cubic meter (0.000002 ounces per cubic foot). They also find that
the fog was not uniform but tended to decrease in thickness toward the
surface. As the Martian night wears on, the surface of the planet cools
below the frost point and water vapor in the atmosphere gets deposited
on the ground. As the atmosphere is mixed by turbulence, more water is
brought to lower altitudes, adding to the growing frost layer.

Ice crystals also form in the air and precipitate to the ground from
successively higher altitudes. The researchers estimate that by the time
the Sun started to rise in the morning, 2.5 micrograms (0.000000088
ounces) of snow and frost would have coated the surface of Mars in the
northerly region around the Phoenix Lander.

Source:
/Geophysical Research Letters,/ doi:10.1029/2010GL046315, 2011
http://dx.doi.org/10.1029/2010GL046315

Title: Observations of near-surface fog at the Phoenix Mars landing site

Authors: John E. Moores, L?once Komguem and James A. Whiteway: Centre
for Research in Earth and Space Science, York University, Toronto,
Ontario, Canada;

Mark T. Lemmon: Atmospheric Sciences Department Texas A&M University,
College Station, Texas, USA;

Cameron Dickinson: MacDonald Dettwiler and Associates Space Missions,
Brampton, Ontario, Canada;

Frank Daerden: Division of Planetary Aeronomy, Belgian Institute for
Space Aeronomy, Brussels, Belgium.

[snip]

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Received on Thu 24 Mar 2011 06:12:47 PM PDT