Giant glacial belts that hide under Mars' surface dust contain enough water to cover the entire planet.
The Red Planet has distinct polar ice caps, but glaciers buried at its central latitudes in both the southern and northern hemispheres have remained relatively elusive, the University of Copenhagen, Niels Bohr Institute reported.
Radar measurements allowed scientists to study the size of these glaciers, and estimate how much water they are composed of. These measurements, made by the NASA satellite, Mars Reconnaissance Orbiter, were combined with ice flow modeling to reveal the nature of the mysterious features.
"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," said Nanna Bjørnholt Karlsson, a postdoc at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.
The researchers were able to obtain solid high-resolution data for some regions of Mars, but only sparse data was available for other areas. To get around this they supplemented the lacking data with information about ice flow taken from better-studied areas of the Red Planet. This method allowed them to calculate how "thick and voluminous" the ice is across the glacial belts. The fact that the ice has not evaporated suggests the layer of dust acts as protection.
"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," Karlsson said.
The findings were reported in a recent edition of the journal Geophysical Research Letters.
