As ESA’s SMOS satellite tv for pc celebrates 10 years in orbit, one more consequence has been added to its checklist of successes. This outstanding satellite tv for pc mission has proven that it may be used to measure how the temperature of the Antarctic ice sheet adjustments with depth – and it’s a lot hotter deep down.
The Antarctic ice sheet is, on common, about 2 km thick, however in some locations the bedrock is nearly 5 km beneath the floor of this big polar ice cap.
Most of us would in all probability suppose that the temperature of ice, irrespective of how thick, stays just about the identical all through: mainly very chilly
Nonetheless, though the floor of the ice sheet is chilly, the temperature will increase with depth primarily due to the basal geothermal heating from beneath Earth’s crust. In locations, it’s heat sufficient to soften the ice, which accounts for the presence of lakes and an unlimited hydrological community on the bedrock.
However, there may be little correct info on precisely how temperature varies with depth aside from from ice core borehole places.
Because the large white ice sheets that blanket Antarctica and Greenland replicate incident photo voltaic radiation again out into area, they’re extraordinarily vital regulators within the local weather system and, subsequently, play a key position within the well being of our planet.
However, ice sheets are additionally victims of local weather change. For instance, this yr scientists found that warming ocean waters have induced the ice to skinny so quickly that a quarter of the glacier ice in West Antarctica is now unstable.
With melting ice sheets largely chargeable for rising sea ranges, which, in flip, threaten hundreds of millions of people all over the world, it’s vital that extra is known about how temperature influences ice-sheet dynamics.
Satellite tv for pc information are used, specifically, to measure adjustments within the peak of ice sheets and consequently their ‘mass steadiness’, the place the ice sheet ends and the floating ice cabinets start – their grounding strains, their floor temperature and how briskly ice streams move.
Nonetheless, temperature is without doubt one of the issues that determines ice viscosity and the way ice flows and slides over the bedrock beneath. In flip, ice move impacts the temperature profile by way of pressure heating – so it’s a sophisticated course of.
Temperature info can be elementary for understanding the presence of aquifers inside or on the backside a part of ice sheets. This may be related for indicating the presence of sub-glacial lakes, for instance, which, in flip, affect ice-sheet dynamics.
How temperature varies in line with the depth of the ice will not be one thing that could possibly be measured from area till now – however in line with a paper printed not too long ago in Science Direct, SMOS is opening up new alternatives to take action.
Giovanni Macelloni from the Institute of Utilized Physics ‘Nello Carrara’ of the Nationwide Analysis Council (IFAC-CNR) in Italy, mentioned, “We usually get ice-sheet temperature profiles from fashions, or from in situ measurements taken in boreholes – however these are clearly pretty sparse.”
Data on temperature from area has, up to now, been restricted to the floor or simply beneath the floor from thermal-infrared sensors and microwave sensors.
The researchers from IFAC-CNR and the Institute of Environmental Geosciences in France, subsequently used ESA’s SMOS satellite tv for pc to see if there’s a approach of gaining this info fairly than counting on fashions and boreholes.
“We mixed SMOS’ L-band passive microwave observations over Antarctica with glaciological and emission fashions to deduce info on glaciological properties of the ice sheet at numerous depths, together with temperature,” continued Dr Macelloni.
“With temperature enjoying such an vital position in ice-sheet dynamics, we’re blissful to say that our analysis, in comparison with fashions, exhibits a greater estimation of temperature improve with depth, with the most important variations near the bedrock.
“SMOS is clearly opening up extra potentialities that we ever thought when it was launched 10 years in the past.”