Soil Moisture at Meridiani

(Christopher M. Jones) wrote in message . com...
(Pedro Rosa) wrote in message . com...
The underground water is mostly concentrated on the Polar regions and
above 40 latitude.

This is an incorrect assumption based on incomplete
data. We know that the permafrost (or, if you like,
the high concentrations of underground Hydrogen, most
likely as H2O) extends some distance away from the
polar caps, but we do not yet know how far. The
data that points to this conclusion comes from the
Mars Odyssey Neutron Spectrometer, which measures
properties of the Martian surface only down to a
certain depth. We don't yet know how deep the
permafrost layers near the poles are and therefore we
do not know if there are permafrost layers deeper
than can be detected via the neutron spectrometer
below much of the rest of the surface of Mars.
There is a strong possibility that the permafrost
layers are deep, and that there exist permafrost
layers over most of the Martian surface with an
upper boundary at a depth corresponding to a
similar temperature as for the upper boundary of
the polar deposits (which would be deeper on
regions farther from the poles).

This is, of course, merely speculation, but the key
here is that the data we have is only a lower limit,
not an upper limit.

Myabe you have a point here. Still I didn't read the Odyssey's data on
that. I based my observations on the distribuion of streaks with a
clear signal that the agent is a fluid. Also I took into attention
data on the presence of water on the Polar caps.

Now I have a question. I made an assumption that water layers in
Arabia are mostly in a range 5-50 meters deep underground. Note that I
think they are mostly remnants of the surface water that once existed
in Mars, the density of the streaks suggests that. They are mostly
concentrated near the 5 meter level, going deeper due to local
specificities of the rocks or due to the presence of craters (in the
latter they may be a lot deeper). Can Odyssey sniff such level?

And note, as I said they are remnants. They can be only seen in some
regions and not in others. Janssen's crater is one of the biggest hot
spots for the presence of water. Maybe because that central crater
there seems quite recent.