Evolution of the cracks within the Pine Island Glacier
Rising cracks within the Pine Island Glacier
The Copernicus Sentinel-1 and Sentinel-2 satellites have revealed new cracks, or rifts, within the Pine Island Glacier – one of many major ice arteries within the West Antarctic Ice Sheet. The 2 giant rifts had been first noticed in early 2019 and have every quickly grown to roughly 20 km in size.
Mark Drinkwater, Head of the Earth and Mission Sciences Division at ESA, says, “These new rifts appeared very quickly after final yr’s main calving of iceberg B46. Sentinel-1 winter monitoring of their progressive extension indicators that a new iceberg of comparable proportions will quickly be calved.”
Pine Island Glacier, together with its neighbour Thwaites glacier, join the centre of the West Antarctic Ice Sheet with the ocean – collectively discharging vital portions of ice into the ocean.
These two glaciers have been dramatically dropping ice over the past 25 years. Owing to their extraordinarily distant location, satellites play a crucial position in measuring and monitoring Antarctic glaciology – revealing the timing and tempo of glacial retreat in Antarctica.
Because the early 1990s, the Pine Island Glacier’s ice velocity has elevated dramatically to values which exceed 10 m a day. Its floating ice entrance, which has a mean thickness of roughly 500 metres, has skilled a collection of calving occasions over the previous 30 years, a few of which have abruptly modified the form and place of the ice entrance.
These modifications have been mapped by ESA satellites because the 1990s, with calving occasions occurring in 1992, 1995, 2001, 2007, 2011, 2013, 2015, 2017 and 2018. The final of which, named B46 by the US Nationwide Ice Heart, was roughly 226 sq. km in measurement.
The ERS-1, ERS-2, Envisat and Copernicus Sentinel-1 satellites have beforehand supplied photographs with to observe modifications in these glaciers. With routine, year-round Copernicus Sentinel-1 photographs, it’s attainable to trace modifications within the pace of the ice movement, to observe the migration of the grounding line, and the event of fractures and rifts which finally result in iceberg calving occasions.
Importantly, Copernicus Sentinel-1’s superior artificial aperture radar (SAR) can picture Earth’s floor via rain and cloud, day or night time. That is significantly helpful for monitoring Antarctic areas all through the extended durations of winter darkness.
Lately, the frequency of Pine Island Glacier calving occasions has elevated. At present, the glacier is noticed to be dropping mass by a mixture of calving occasions along with robust basal melting, the place heat ocean currents erode the underside of the floating ice shelf. Because the ice shelf each thins and calves huge icebergs, the glacier discharge is unable to replenish the ice misplaced and the ice shelf entrance recedes from its earlier place.
“Lengthy-term measurements of West Antarctic Ice Sheet glaciers comparable to Pine Island are crucial to understanding modifications to the speed of lack of ice mass into the ocean, and thus Copernicus Sentinel-1 has change into elementary to gauging Antarctica’s contribution to rising sea ranges,” says Mark Drinkwater.