“Radar observations of the ice cap provide a detailed history of ice accumulation and erosion associated with climate change”, said Isaac Smith of the Southwest Research Institute (SwRI).
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With the aid of data from MRO’s Shallow Subsurface Radar (SHARAD), researchers have been able to analyse variations in the layer properties by producing images known as radargrams that are like vertical slices though the layers of ice and dust at the martian poles. Measuring this time delay between the signals along with tracing out the entire ice cap by the orbiter, Smith and his team got a profile of the entire ice cap down to 300 meters below the surface.
They reveal the planet looks to be experiencing the latest in a series of climate change swings which are believed to be caused by it tilting on its axis.
A science team led by Adrian Brown of the SETI Institute has measured the seasonal changes in Mars’ northern ice cap and finds a net deposition each year that’s slightly more than the thickness of a human hair.
That may seem counterintuitive, since Mars’ ice age is in retreat. The results will support modeling efforts to understand the martian climate, looking at the movement of ice from poles to mid-latitudes during climate cycles. Since then, roughly 20,872 cubic miles of ice has built up on the poles. “Its color would change”.
The climate on Mars … and Earth?
Ice ages on Mars are driven by similar processes responsible for ice ages on Earth, including changes in the planet’s orbit and tilt, which affects the amount of solar radiation each latitude receives. On Mars, the exaggerated tilt determines how much sunlight reaches certain regions.
“It will be whiter – it will be even brighter than it is now and it’s really bright right now”, he said. Eventually they will spread out over the continents, making an ice age. That’s why, when Smith and his colleagues observed an uptick in the rate of accumulation of ice near the surface of Mars’ north polar cap, they knew that an ice age had to have ended recently.
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Radar measurements of Mars’ polar ice caps reveal that the mostly dry, dusty planet is emerging from an ice age, following multiple rounds of climate change. With Earth possessing oceans and life, it complicates the model significantly. Researchers say that one of the most important findings of their study is the discovery of thick carbonate deposits across the popular Huygens basin than what was originally believed. “Previously those models … started with guesses”, Smith said.
