The Curious Case of Greenland’s Melting Ice Sheets
Climate change continues to make the world warmer than usual resulting to the rapid increase in the melting of ice caps. There have been previous reports about the alarming rate of melting occurring in the coastal region of Greenland but surprisingly, about 40 percent of ice sheets in the central region of Greenland show no sign of melting at all.
Baffled by this phenomenon, researchers were determined to understand why ice sheets in the coastal region of Greenland experience severe melting while some of the more central regions are unharmed by the warming climate.
Observing Greenland inner ice sheets is difficult due to heavy snowfalls and heavy winds; this is why researchers instead shifted their focus on the atmosphere above the island.
The researchers then measured the water isotopes in the water vapor in the atmosphere.
According to their findings, published in the journal Science Advances, Greenland's inner ice sheets have a very stable weather system in its atmosphere. Just a few meters above the surface and, the air is very stagnant and is very cold and dry. Meanwhile, about 100 meter up from the cold and dry layer, the air tends to be more variable and warmer.
"There was a high content of the oxygen isotope 18O both in the lowest layer of air near to the ice and in the higher layer of air. But in between the two air layers at a height of 2-4 meters there was a layer with a lower content of 18O. So there was a boundary layer that separated the two layers in the atmosphere. We were thus able to see a direct disconnection between the surface of the ice and the atmosphere above it - it would not have been possible to discover this if we had only looked at the water vapour amount in the air," explained Hans Christian Steen-Larsen from the Centre for Ice and Climate at the Niels Bohr Institute said in statement.
With this discovery, researchers then concluded that lower precipitation due to the boundary layer serves as protection against melting in the inner regions of Greenland. The air above the boundary level can form fog but it is not dense enough to precipitate causing it to evaporate again. Also, this thin layer of fog serves as a layer of protection preventing evaporation from the surface of the ice.