September 27, 2021

NASA’s Oceans Melting Greenland Mission Leaves for Its Last Field Trip

2 min read

A Greenland glacier meets the ocean. Credit: NASA/JPL-Caltech

NASA’s airborne Oceans Melting Greenland (OMG) mission begins its final survey of glaciers that flow from Greenland into the ocean. OMG is completing a six-year mission that is helping to answer how fast sea level is going to rise in the next five, 10, or 50 years.

Greenland’s melting glaciers currently contribute more fresh water to sea level rise than any other source does. The glaciers are melting six or seven times faster today than they were only 25 years ago, and OMG is the first NASA mission to focus solely on what the ocean contributes to this ice loss. That’s a critical part of helping improve calculations of future melt rates so that coastal communities worldwide can take timely precautions to limit the damage from higher seas.

Ice melts faster in warmer water than it does in colder water, but before the OMG mission, the temperature of the ocean water touching Greenland’s more than 200 coastal glaciers was largely unknown. Simply measuring the temperature at the ocean surface isn’t enough. The upper layer of the ocean around Greenland consists largely of Arctic meltwater, and it’s very cold – sometimes even below freezing temperature. About 600 or 700 feet (200 meters) down is a layer of warmer, saltier water carried northward from less-frigid latitudes. Many glacier fronts extend down into the warmer-water zone, where they melt more rapidly.

This visualization explains how a glacier melts from below. Credit: NASA’s Scientific Visualization Studio

No satellite instrument can peer deep into the ocean to measure temperature. The only way scientists have found to do that is to drop a probe into the water and let it sink. That’s what the OMG team has been doing every summer since 2016.

This year, Principal Investigator Josh Willis of NASA’s Jet Propulsion Laboratory in Southern California and OMG Project Manager Ian McCubbin, also of JPL, will fly around the entire coast of Greenland with a crew of pilot and engineers in a specially modified DC-3 aircraft. From early August through early or mid-September, they’ll drop probes out of the belly of the plane into the ocean at about 300 target locations in front of glaciers. As the probes sink, they transmit temperature and salinity readings by radio waves to the plane overhead until they reach the ocean floor.

The article is published courtesy of NASA’s Jet Propulsion Laboratory

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