NASA reports newest Greenland Maps Show more Glaciers at Risk of Accelerated Melting

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November three, 2017 |
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Written by Carol Rasmussen
NASA’s Earth Science News Team

NASA - National Aeronautics and Space AdministrationWashington, D.C. – New maps of Greenland’s coastal seafloor and bedrock beneath its large ice sheet present that two to 4 occasions as many coastal glaciers are susceptible to accelerated melting as beforehand thought.

Researchers on the University of California at Irvine (UCI), NASA and 30 different establishments have printed probably the most complete, correct and high-resolution reduction maps ever fabricated from Greenland’s bedrock and coastal seafloor. Among the various knowledge sources included into the brand new maps are knowledge from NASA’s Ocean Melting Greenland (OMG) marketing campaign.

Left: Greenland topography color coded color-coded from 4,900 feet (1,500 meters) below sea level (dark blue) to 4,900 feet above (brown). Right: Regions below sea level connected to the ocean; darker colors are deeper. The thin white line shows the current extent of the ice sheet. (UCI)

Left: Greenland topography colour coded color-coded from four,900 toes (1,500 meters) beneath sea degree (darkish blue) to four,900 toes above (brown). Right: Regions beneath sea degree related to the ocean; darker colours are deeper. The skinny white line reveals the present extent of the ice sheet. (UCI)

Lead writer Mathieu Morlighem of UCI had demonstrated in an earlier paper that knowledge from OMG’s survey of the form and depth, or bathymetry, of the seafloor in Greenland’s fjords improved scientists’ understanding not solely of the shoreline, however of the inland bedrock beneath glaciers that movement into the ocean.

That’s as a result of the bathymetry the place a glacier meets the ocean limits the probabilities for the form of bedrock farther upstream.

The nearer to the shoreline, the extra beneficial the bathymetry knowledge are for understanding on-shore topography, Morlighem mentioned. “What made OMG unique compared to other campaigns is that they got right into the fjords, as close as possible to the glacier fronts. That’s a big help for bedrock mapping.”

Additionally, the OMG marketing campaign surveyed mbadive sections of the Greenland coast for the primary time ever. In fjords for which there are not any knowledge, it’s troublesome to estimate how deep the glaciers prolong beneath sea degree.

The OMG knowledge are solely one in all many datasets Morlighem and his crew used within the ice sheet mapper, which is known as BedMachine. Another complete supply is NASA’s Operation IceBridge airborne surveys. IceBridge measures the ice sheet thickness straight alongside a aircraft’s flight path.

This creates a set of lengthy, slim strips of information slightly than a whole map of the ice sheet. Besides NASA, almost 40 different worldwide collaborators additionally contributed numerous kinds of survey knowledge on totally different components of Greenland.

No survey, not even OMG, covers each glacier on Greenland’s lengthy, convoluted shoreline. To infer the mattress topography in sparsely studied areas, BedMachine averages between present knowledge factors utilizing bodily ideas such because the conservation of mbad.

The new maps reveal that two to 4 occasions extra oceanfront glaciers prolong deeper than 600 toes (200 meters) beneath sea degree than earlier maps confirmed. That’s unhealthy information, as a result of the highest 600 toes of water round Greenland comes from the Arctic and is comparatively chilly. The water beneath it comes from farther south and is 6 to eight levels Fahrenheit (three to four levels Celsius) hotter than the water above. Deeper-seated glaciers are uncovered to this hotter water, which melts them extra quickly.

Morlighem’s crew used the maps to refine their estimate of Greenland’s whole quantity of ice and its potential so as to add to world sea degree rise, if the ice have been to soften utterly — which isn’t anticipated to happen throughout the subsequent few hundred years. The new estimate is larger by 2.76 inches (7 centimeters) for a complete of 24.34 toes (7.42 meters).

OMG Principal Investigator Josh Willis of JPL, who was not concerned in producing the maps, mentioned, “These results suggest that Greenland’s ice is more threatened by changing climate than we had anticipated.”

On October 23rd, the five-year OMG marketing campaign accomplished its second annual set of airborne surveys to measure, for the primary time, the quantity that heat water across the island is contributing to the lack of the Greenland ice sheet.

Besides the one-time bathymetry survey, OMG is ambading annual measurements of the altering top of the ice sheet and the ocean temperature and salinity in additional than 200 fjord places. Morlighem seems to be ahead to enhancing BedMachine’s maps with knowledge from the airborne surveys.

The maps and badociated badysis are in a paper titled “BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mbad conservation” in Geophysical Research Letters.

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Carol Rasmussen, Glaciers, Greenland, Greenland glaciers, NASA, NASA’s Earth Science News Team, National Aeronautics and Space Administration, University of California at Irvine, washington d.c.





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