robertmcgrath posted: " Up Greenland way, in between the summer melt (and rain!) and the winter snowfall, there is a season of dust storms. We don't think of Greenland as a dusty place, but it has its own particular kind of dust: glacial silt, called "flour", the ground up r"
Up Greenland way, in between the summer melt (and rain!) and the winter snowfall, there is a season of dust storms.
We don't think of Greenland as a dusty place, but it has its own particular kind of dust: glacial silt, called "flour", the ground up rock grit from glaciers scraping rock. Eventually, this dust turns into soil. Mostly this grit is under the glaciers or snowpack.
But at the end of summer, with the glaciers at their minimum, large areas of rock and silt are exposed to the wind and streams. The glacial flour is blown into the sky and washed into the ocean.
This fall, NASA captured plumes of this dust from orbit.
NASA Earth Observatory images by Lauren Dauphin, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview and VIIRS data from NASA EOSDIS LANCE, GIBS/Worldview, and the Suomi National Polar-orbiting Partnership. (From [1])
Kathryn Hansen reports that this dust can be carried kilometers out to sea, where it falls as mineral rich fertilizer which can support algal blooms [1].
Dust on snow or ice makes the surface darker and absorbs more heat from the sun. Algae in the water is darker, and also absorbs more heat. So, increased dust storms potentially contribute at least a little to warming and melting the ice and snow.
As the ice recedes in Greenland, there will be more and more rock and silt exposed, which will result in larger and longer dust storms. I.e., this is another part of the positive feedback that is accelerating the melting of Greenland's ice.
WordPress.com
No comments:
Post a Comment