According to the new studies carried out by NASA’ Oceans Melting Greenland (OMG) campaign Greenland Ice Sheets are Melting From Below.
The interesting knowledge about the Greenland’s ice structures and its melting is being generated by NASA’s Oceans Melting Greenland (OMG) campaign. It’s a five year long mission started in 2015.
Ocean Melting Greenland (OMG) Campaign to Enhance the Knowledge on Melting of Greenland Ice Sheets
Greenland’s coastline is 27,000-miles long. The OMG campaign studies the glaciers and ocean along the coastline. The aim of the campaign is to know where and how fast the seawater is melting the glacial ice.
Both boats and aeroplanes are being used for the OMG campaign. Through the coastal channels the warm salty water of the Atlantic ocean reaches inside and melts ice sheets. The campaign is trying to make high resolution maps of the Greenland’s coast and pathways to get the detailed picture.
NASA’s G3 research plane is being used in the campaign. With the help of the sensors it reveals the temperature and salinity of the ocean up to the depth of 3000 feet. With the help of the GLISTIN radar it reveals the thinning and retreat of the glaciers from the below. These observations will help in bringing accuracy in the sea level rise projections.
As per the information provided by NASA referring two recent research publications that used OMG data, an understanding is being developed onhow glaciers and ocean currents are interacting along Greenland’s west coast.
The OMG campaign is also helping towards improvement on seafloor maps used to predict future melting and subsequent sea level rise.
Few very interesting observations have come out from this campaign. According to the observations the sea water that surrounds the Greenland consists of two layers. The topmost layer is around ~600 feet deep. This layer contains relatively fresh cold water coming from the arctic while the layer below is salty & around 3 to 4 degrees Celsius warmer than the top layer. It is also saltier than the upper layer.
This subsurface layer is formed by the oceanic water coming from the south. The top layer weighs way less than the saltwater layer and therefore the two layers don’t mix much. Together it appears as if there is a cold fresh water river flowing above the warm salty ocean.
There are many coastal glaciers in Greenland. The interaction between the glaciers and the circulating water decides the rate of the ice melt.
The data gathered from the OMG observations reveal that if the sea shore in front of the coastal glaciers is shallow glaciers interact only with the top frigid freshwater. This reduces the rate of ice melt. Contrary, if the seafloor in front of the glaciers is deep, the warm subsurface layers melt the glaciers relatively rapidly from below.
These are the initial findings. Once the refined sea floor maps become available lot many interesting happening will reveal themselves.
Why the knowledge about the melting of the Greenland Ice Sheets is important?
Greenland is the world’s largest island. Thick ice sheets cover 80% of the area of Greenland. More precisely 1,710,000 square kilometers area of Greenland is ice sheet covered. In most of the places the ice sheet is as thick as 2 km while it is ~3 km thick in the thickest areas.
Total 90% of the ice present in the earth is present as ice sheet in Antarctica and Greenland. As an estimate, the fresh water present as ice sheets in Greenland is so much that if all of it gets melted, it would lead to the rise in the oceans by more than 20 feet. But the relief is that it is not going to happen soon.
But the scientists are unanimously of the opinion that if it continues to melt at the present rate, by the end of this century it will lead to the sea level rise by 6-8 feet. The possible causes of the increased rate of Greenland ice sheets melting are rise in the sea and land temperatures, changing weather patterns etc.
The predicted sea level rise will have impacts on lives and livelihoods of billions of people live in the low land areas. Hence the melting of Greenland ice sheets is a phenomenon the scientists are keen to know more and more about.