March 1–5, 2010 ... rogram.pdf

Here's an interesting one I found:

A. Johnsson1, L. Johansson1, M. Zanetti2, D. Reiss2, E. Hauber3, H.
Hiesinger2, R. M. Ulrich4, M. Olvmo1, E. Carlsson5, R. Jaumann3, F.
Trauthan3, F. Preusker3, H.A.B. Johansson6, and S.

Near the end of their abstract, the authors do raise the possibility
that freeze-thaw cycles under the present atmospheric regime could be
possible and are the origin of these stripe-like patterns. But at the
beginning they state:

"Due to the current
temperature and pressure regime on Mars soil
moisture and active layer processes are not likely to
occur [4]"

which rather implies at the start they don't expect this to be the
likely answer.

However, I looked at the cited report by Kreslavsky and Head and found
what they calculate is the *average* temperature according to latitude
and obliquity on Mars:

M. A. Kreslavsky1,2, and J. W. Head1.
"Introduction: Estimation of the summer dayaverage
surface temperature on inclined surfaces on
Mars has been done in [1] with a global climate model
(GCM) for different obliquities. These calculations
showed that starting from ~35° obliquity, the maximal
day-average temperature reaches the ice melting point
at high latitudes; for even higher obliquity, the dayaverage
temperature exceeds 0°C at lower latitudes, up
to 40° latitude at 45° obliquity, but only at 20-30°-
steep pole-facing slopes."

This is a real sore point with me. I have found that quite often Mars
scientists when they want to argue against the possibility of liquid
water on present day Mars, they will always talk about the lowest
temperatures or the average temperature on Mars, when clearly it
should be the *maximum* temperature that should be mentioned. I
discussed this in a post to sci.astro copied below.
Then given the fact that several recent observations have shown
current ground ice, perhaps with a thin dust cover, from mid latitudes
down to even near equatorial latitudes on Mars, a more useful
calculation would be towards how long the temperatures stay above zero
at particular latitudes and how much liquid ground water would be
expected to be produced given the observed amounts of ground ice at
those latitudes. As a starting point towards that, here's an article
that did calculate when the maximum temperature is above the melting
point of water on present day Mars:

Use of spacecraft data to derive regions on Mars where liquid water
would be stable.
Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 5, 2132-2137, February 27,

Could the amount of current ground water generated produce *in current
times* the young gullies and larger channels found on Mars ?

Bob Clark

Newsgroups: sci.astro, alt.sci.planetary, alt.astronomy,
sci.geo.geology, sci.astro.amateur
From: (Robert Clark)
Date: 23 Mar 2002 06:08:57 -0800
Local: Sat, Mar 23 2002 9:08 am
Subject: Mars temperatures - they're doing it again!

Probably most regular readers of sci.astro know by now my view on the
temperatures on Mars and the possibility of liquid water on the Red
Planet, cf.,

From: Robert Clark (
Subject: NASA proving Levin's theory right about liquid water on Mars?
Newsgroups: sci.astro,, sci.astro.seti, sci.physics
Date: 2000-11-19 10:10:10 PST
[Expired link. Try instead:]

A real pet peeve of mine is that *usually* scientists cite the
lowest temperatures or average temperatures on Mars to conclude that
liquid water can not exist on Mars.
My view is that a more relevant temperature to give is the maximum
temperature on Mars. I'm fairly certain for example that the average
temperature in Fairbanks, Alaska is below zero Celsius, but would you
conclude then from that that liquid water can not exist in Fairbanks,
Alaska? (BTW, here's an image of the Chena River in Fairbanks: )
[Expired link. Try instead:]

This occurred again in regards to the recent announcement of the
results from Mars Odyssey indicating large amounts of water in the
southern hemisphere:

Odyssey Finds Large Concentrations of Water on Mars.
"The scientists know that the water is ice rather than liquid,
because the temperatures on Mars are well below freezing. The average
temperature of Mars is –63 C (–81 F) and the instruments of Odyssey
indicate the coldest temperature in the Southern Hemisphere right now
is -101 C (–150 F).
"It's just too darn cold for it to be liquid water,' says Boynton."
[Expired link. Try instead:]

What's interesting here is that they refer to Odyssey instruments
giving this coldest temperature. Yet there was an infrared image
released from the THEMIS infrared imager on Odyssey showing above
zero temperatures being reached in the southern hemisphere of Mars:

First THEMIS Infrared and Visible Images of Mars.

Also, the TES imager on Mars Global Surveyor has shown that
temperatures can exceed 20 C as far south as 60 S latitude:
[Expired link. Try instead:]

Since the Odyssey infrared imager has a better resolution than the
TES instrument, I presume the THEMIS instrument would confirm this as

Bob Clark