150 billion cubic meters of water ice on Mars in glaciers covered by dust
Mars has polar ice caps, but also has belts of glaciers at its central latitudes in both 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 Letter.
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.
“We have calculated that the ice in the glaciers is equivalent to over 150 billion cubic meters of ice, that much ice could cover the entire surface of Mars with 1.1 meters of ice. The ice at the mid-latitudes is therefore an important part of Mars’ water reservoir,” explains Nanna Bjornholt Karlsson.
That the ice has not evaporated out into space could actually mean that the thick layer of dust is protecting the ice. The atmospheric pressure on Mars is so low that water ice simply evaporates and becomes water vapour. But the glaciers are well protected under the thick layer of dust.