More on "Frost on the rover solar panels".

From: Robert Clark (rgregoryclark_at_yahoo.com)
Date: 12/25/04 

Date: 25 Dec 2004 12:58:34 -0800

Imaging at the Opportunity rover landing site in Meridiani Planum
confirms observations using the HEND instrument on Mars Observer that
water/ice is deposited near the equator seasonally on Mars:

Space Sciences
Whoa! Frost on the solar panels?
Posted by Robert Clark on 12/14/2004 7:32:38 AM
In Reply to: Sabkha or playa, take your pick... posted by Nick Hoffman
on 12/13/2004 6:23:08 PM
http://habitablezone.com/space/messages/360805.html

However, the HEND instrument shows the greatest amount is deposited
during southern Summer:

47 - EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER IN THE SURFICIAL
MARTIAN REGOLITH BASED ON ANALYSIS OF THE HEND MAPPING DATA.
R.O. Kuzmin, E.V. Zabalueva, I.G. Mitrofanov, M.L.Litvak, A.V.
Parshukov,
V.Yu.Grin'kov, W. Boynton, R.S. Saunders.
"As it well seen from fig.1b,c,d, two distinctive "hollows" of
neutrons flux reduction have been appeared in the northern hemisphere
during northern summer at Ls=130°-170° and in first half of northern
winter at Ls=270°-330°, being extended from high to low latitudes. At
that, later "hollow" (Ls=270°-330°) is characterized by much
stronger reduction of the neutrons flux and it traces from northern
polar region up to low latitudes in the southern hemisphere. The first
"hollow" is related with periods of the northern middle summer,
while the second one - with of the southern middle summer. In both
case the residual polar caps serve as main source of the water in the
Martian atmosphere."
p. 2
http://www.geokhi.ru/~planetology/theses/47_kuzmin_et_al.pdf

Opportunity landed just barely after this time in southern Summer at
about LS 340° (LS stands for solar longitude and indicates Mars
position in its orbit.)
However, it is notable that Spirit did land near the end of the time
period of Ls=270°-330°. Spirit is closer to the southern pole and
this may explain how could experience deposition during this period
while apparently not during the current northern Summer. Then the
controversial indications of mud at the Spirit landing site early in
the mission may indeed have been indications of this summer-time water
deposition.
Opportunity has observed clouds during the current water deposition
period and since the amount of atmospherically deposited water is
greater during southern Summer, we would expect the cloud density to be
even greater then. Indeed it could be of sufficient density to allow
precipitation which could reach the ground as rain.
The next Ls=270°-330° period begins in August, 2005.

Come on Opportunity!

Bob Clark

Robert Clark wrote:
> Whoa! Frost on the Mars rover solar panels?
>
> >From the Mars rover press release:
>
> December 13, 2004
> Mars Rovers Spot Water-Clue Mineral, Frost, Clouds
> "A portion of Mars' water vapor is moving from the north pole toward
> the south pole during the current northern-summer and southern-winter
> period. The transient increase in atmospheric water at Meridiani,
just
> south of the equator, plus low temperatures near the surface,
> contribute to appearance of the clouds and frost, Wolff said. Frost
> shows up some mornings on the rover itself. The possibility that it
has
> a clumping effect on the accumulated dust on solar panels is under
> consideration as a factor in unexpected boosts of electric output
from
> the panels."
> http://marsrovers.jpl.nasa.gov/newsroom/pressreleases/20041213a.html
>
> Rover scientists had speculated that some of this frost may melt to
> liquid to contribute to the clumping. Note that actual SURFACE
> temperatures can exceed 0 C when the air temperature is below
freezing,
> when the surface is exposed to direct sunlight (it's southern winter
at
> the landing sites now.) This would be especially true of a dark
surface
> like the solar panels specifically designed to absorb sunlight.
> What is the expected temperatures of the solar panels during the
> hottest portion of the day? Do the cameras actually observe the frost
> on solar panels? If so then we may actually be able to observe the
> transition to liquid during late morning to early afternoon.
> Note that the accumulation of this frost confirms visually what has
> been found by the Mars Odyssey HEND hydrogen mapper that water
> accumulates on Mars in near equatorial locations during northern and
> southern Summer:
>
> Further evidence for current liquid water near the equator on Mars.
> Posted by Robert Clark on 11/25/2004 12:39:16 AM
> http://habitablezone.com/space/messages/358773.html
>
> This visual evidence from the rovers further supports the suggestion
by
> the authors of the HEND report that this increase is due to
atmospheric
> deposition. Of the various explanations offered by the authors, it
> supports the suggestion the water is in free form, not bound in
sulfate
> or other evaporite:
>
> 47 - EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER IN THE
SURFICIAL
> MARTIAN REGOLITH BASED ON ANALYSIS OF THE HEND MAPPING DATA.
> R.O. Kuzmin, E.V. Zabalueva, I.G. Mitrofanov, M.L.Litvak, A.V.
> Parshukov, V.Yu.Grin'kov, W. Boynton, R.S. Saunders.
> http://www.geokhi.ru/~planetology/theses/47_kuzmin_et_al.pdf
>
> The authors suggest frost or ice. My opinion is that during warm
> *surface* temperatures this frost can melt to liquid, particularly
for
> low albedo (dark), low thermal inertia (easy to heat up) materials,
> such as the solar panels.
>
>
> Bob Clark
>
>
>
> Robert Clark wrote:
> > In this post to the Habitablezone.com/space/ bbs I discuss seasonal
> > changes observed by the Gamma Ray Spectrometer on Mars Odyssey in
> near
> > equatorial water on Mars:
> >
> > Latest Mars Odyssey observations prove free water at equator.
> > Posted by Robert Clark on 6/27/2003 8:03:48 AM.
> > http://www.habitablezone.com/space/messages/286216.html
> >
> > A report presented to October, 2004 Vernasky/Brown Conference
> > provides further evidence of these seasonal changes:
> >
> > 47 - EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER IN THE
> SURFICIAL
> > MARTIAN REGOLITH BASED ON ANALYSIS OF THE HEND MAPPING DATA. R.O.
> > Kuzmin, E.V. Zabalueva, I.G. Mitrofanov, M.L.Litvak, A.V.
Parshukov,
> > V.Yu.Grin'kov, W. Boynton, R.S. Saunders.
> > http://www.geokhi.ru/~planetology/theses/47_kuzmin_et_al.pdf
> >
> > The authors note an increase in northern near equatorial regions
of
> > the water content during the northern Summer and southern Summer.
> They
> > argue this should be due to transport of water vapor to the equator
> > from northern polar regions during northern Summer and from the
> > southern polar regions during southern Summer. Evidence for this is
> > its seasonal nature but also the fact the highest increase is shown
> in
> > the measurements closest to the surface. These are figures 1d and
1c,
> > which show the water content within 10cm (4 inches) and 20-30cm
(8-12
> > inches), respectively. Note the highest increase in the
measurements
> > occurs within 10cm (4 inches) of the surface.
> > The authors suggest either the water vapor is deposited as frost
on
> > the surface or incorporated into clathrates or evaporates near
> > surface:
> >
> > "The observing maximum value of the reduction of the higher energy
> > fast neutrons flux (in the period with Ls=270°-330°) approaches ~
> > 20%.That is the abundance of the water (in form of water ice or
> > clathrate CO2·6H2O) in ~ 10 cm thickness surface layer could be
> > increased notably in the period on. As water source for this
> > apparently serves the water vapor mass transferred meridionally to
> > here from residual southern polar cap due to the significantly
lower
> > partial pressure of H2O over the cold surface of the northern
> seasonal
> > cap and its surrounding region. We suggest that the visible
reduction
> > of the neutrons flux outside of the seasonal cover of the CO2-ice
(up
> > to the equatorial regions), may to be associated with both
> > condensation of the H2O frost on the surface and hydration of a
salts
> > minerals (mostly sulfates and chlorides) contained in the surface
> > layer of the regolith. The neutrons flux reduction observing in the
> > period Ls=130°-170° is rather associated with hydration process
in
> the
> > surface regolith due to high atmospheric humidity in the period."
> > EVIDENCE OF THE SEASONAL REDISTRIBUTION OF WATER IN THE SURFICIAL
> > MARTIAN REGOLITH BASED ON ANALYSIS OF THE HEND MAPPING DATA, p. 2
> >
> > However, note that if it is frost then there are locations near
the
> > equator at low altitude and it would be expected to melt to liquid
> > water at these low elevations sites as seasonal daytime
temperatures
> > increased. (Temperatures near the equator can reach 80 degrees
> > Fahrenheit during daytime in Summer.)
> > Also important to realize is that either the clathrate or
evaporate
> > explanations would require liquid water for their formation and
> within
> > 4 inches of the surface and occurring currently and seasonally.
> >
> >
> > Bob Clark

Relevant Pages