A team of planetary scientists led by Dr Nanna Bjørnholt Karlsson from the University of Copenhagen, Denmark, has calculated the total volume of water ice present in massive belts of glaciers at the mid-latitudes of Mars using radar observations in combination with ice flow modeling.

“We have calculated that the ice in the glaciers is equivalent to over 150 billion cubic meters of ice,” said Dr Bjørnholt Karlsson, the first author on the study published in the journal Geophysical Research Letter.

“This corresponds to a global ice cover of 1.1 m. Thus, the water ice found at mid-latitudes is an important Mars’ water reservoir.”

Recent studies have identified more than 1,300 glacier-like forms in both the planet’s southern and northern hemispheres, and revealed that these features are mainly composed of water ice.

Dr Bjørnholt Karlsson and her colleagues at the University of Copenhagen’s Niels Bohr Institute looked at radar measurements spanning 10 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,” Dr Bjørnholt Karlsson said.

“We then compared this with how glaciers on Earth behave and from that we have been able to make models for the ice flow.”

“From some locations on Mars we have good detailed high-resolution data, while we only have more sparse data from other areas. But by supplementing the sparse data with information about the flow and form of the glaciers from the very well studied areas, we have been able to calculate how thick and voluminous the ice is across the glacier belts.”

“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 vapor. But the glaciers are well protected under the thick layer of dust.”

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Karlsson NB et al. Volume of Martian mid-latitude glaciers from radar observations and ice-flow modelling. Geophysical Research Letters, published online March 18, 2015; doi: 10.1002/2015GL063219