Radar survey offers new insights into Martian climate change

"In the 3D radar volumes, we can identify and map bowl-shaped features that appear to be buried impact craters," said researcher Nathaniel Putzig.
By Brooks Hays  |  Sept. 26, 2017 at 10:15 AM
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Sept. 26 (UPI) -- Scientists have used thousands of 2D radar scans to create 3D subsurface profiles of Mars, revealing new insights into the geologic features of Mars' polar regions.

The new 3D radar images have revealed the location of buried impact craters, as well as the distribution of CO2 and water ices.

The thousands of 2D scans were collected by the Shallow Radar sounder on NASA's Mars Reconnaissance Orbiter, which has passed over the Martian poles more than 2,000 times since it began orbiting the Red Planet in 2006.

Researchers used the new 3D profiles to build more accurate maps of Mars' polar CO2 ice deposits. Their efforts -- detailed this week in the journal Icarus -- suggest there is a great mount of CO2 ice than previously estimated.

"Sublimation of that CO2 ice into the atmosphere -- which is thought to have occurred at various times in Martian history -- would more than double the current atmospheric pressure," Nathaniel E. Putzig, a senior scientist at the Planetary Science Institute in Tucson, Arizona, said in a news release. "That in turn would allow liquid water to be stable at the surface in many more locations than it is today."

Scientists already knew the poles were peppered with CO2 and water ice deposits, but until now, researchers had never before detected or mapped subsurface impact craters on Mars' poles.

"In the 3D radar volumes, we can identify and map bowl-shaped features that appear to be buried impact craters, many of them at the base of the icy layers," Putzig said. "To estimate the age of planetary surfaces, scientists combine information about the number, size, and distribution of craters and knowledge of cratering rates over time within the Solar System."

Researchers estimated the age of the craters at the base of the northern ice cap at roughly 3.5 billion years old. The estimate is in agreement with the age of similar craters on the Martian plains to the south.

By combining 2D scans into 3D profiles, researchers are able to perform their analysis much more efficiently. They were also able to create more detailed maps.

"The 3D makes these types of investigation much more efficient than our work in the past, and some things that were formerly impossible are now done quickly." said PSI research scientist Isaac B. Smith. "This new way of using the radar data saves us from painstakingly mapping every feature in thousands of 2D profiles. With the 3D volumes, we can see things immediately that took months or years to map with the 2D dataset."

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