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Mars Reconnaissance Orbiter Data Reveals Belts of Water Ice Glaciers On Mars

posted by mrcoolbp on Thursday April 09 2015, @03:20AM   
from the belt-driven dept.

NotSanguine writes:

phys.org is reporting that researchers working with radar data from the Mars Reconnaissance Orbiter (MRO) [flash required] have determined that belts of glaciers away from the poles are primarily composed of water ice.

What is more, researchers from the Neils Bohr Institute have been able to use the radar data and ice flow modelling to calculate the volume of water ice present in the glacier belts.

From the Phys.Org article:

Mars has distinct polar ice caps, but Mars also has belts of glaciers at its central latitudes in both the southern and northern hemispheres. A thick layer of dust covers the glaciers, so they appear as surface of the ground, but radar measurements show that underneath the dust there are glaciers composed of frozen water. New studies have now calculated the size of the glaciers and thus the amount of water in the glaciers. It is the equivalent of all of Mars being covered by more than one meter of ice. The results are published in the scientific journal, Geophysical Research Letters.

Several satellites orbit Mars and on satellite images, researchers have been able to observe the shape of glaciers just below the surface. For a long time scientists did not know if the ice was made of frozen water (H2O) or of carbon dioxide (CO2) or whether it was mud.

Using radar measurements from the NASA satellite, Mars Reconnaissance Orbiter, researchers have been able to determine that is water ice. But how thick was the ice and do they resemble glaciers on Earth?

A group of researchers at the Niels Bohr Institute have now calculated this using radar observations combined with ice flow modelling.

Data combined with modelling

"We have looked at radar measurements spanning ten years back in time to see how thick the ice is and how it behaves. A glacier is after all a big chunk of ice and it flows and gets a form that tells us something about how soft it is. We then compared this with how glaciers on Earth behave and from that we have been able to make models for the ice flow," explains Nanna Bjørnholt Karlsson, a postdoc at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

• Re:snow day (Score: 5, Informative) by takyon on Thursday April 09 2015, @04:10AM

  by takyon (881) <takyonNO@SPAMsoylentnews.org> on Thursday April 09 2015, @04:10AM (#168159) Journal

  https://en.wikipedia.org/wiki/Water_on_Mars#Ice_ages [wikipedia.org]

  Mars has experienced large scale changes in the amount and distribution of ice on its surface in its relatively recent geological past, and as on Earth, these are known as ice ages. Ice ages on Mars are very different from the ones that the Earth experiences. During a Martian ice age, the poles get warmer, and water ice then leaves the ice caps and is redeposited in mid latitudes. The moisture from the ice caps travels to lower latitudes in the form of deposits of frost or snow mixed with dust. The atmosphere of Mars contains a great deal of fine dust particles, the water vapor condenses on these particles which then fall down to the ground due to the additional weight of the water coating. When ice at the top of the mantling layer returns to the atmosphere, it leaves behind dust which serves to insulate the remaining ice.

  https://en.wikipedia.org/wiki/Glaciers_on_Mars#Climate_Changes [wikipedia.org]

  It is now widely believed that ice accumulated when Mars' orbital tilt was very different from the present (the axis the planet spins on has considerable "wobble," meaning its angle changes over time). A few million years ago, the tilt of the axis of Mars was 45 degrees instead of its present 25 degrees. Its tilt, also called obliquity, varies greatly because its two tiny moons cannot stabilize it like our moon... Studies have shown that when the tilt of Mars reaches 45 degrees from its current 25 degrees, ice is no longer stable at the poles. Furthermore, at this high tilt, stores of solid carbon dioxide (dry ice) sublimate, thereby increasing the atmospheric pressure. This increased pressure allows more dust to be held in the atmosphere. Moisture in the atmosphere will fall as snow or as ice frozen onto dust grains. Calculations suggest this material will concentrate in the mid-latitudes. General circulation models of the Martian atmosphere predict accumulations of ice-rich dust in the same areas where ice-rich features are found. When the tilt begins to return to lower values, the ice sublimates (turns directly to a gas) and leaves behind a lag of dust. The lag deposit caps the underlying material so with each cycle of high tilt levels, some ice-rich mantle remains behind.

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