Walking in Iceland.
Team Oceans Melting Greenland (OMG) stands on the Greenland Ice Sheet. Notice the long shadows made by small rocks on the ground.
Albedo is part of what has stabilized Earth’s climate for millennia, because under normal conditions, the white of the polar ice reflects light energy back to space, keeping average global temperature stable. The more area covered by ice, the more heat reflected back to space.
I stood for a moment, looking at the ground– a hard, dry, crusty mixture of ice and snow that made an exceptionally satisfying crunch noise as our boots marched through it– and tried to figure out the color: 50 shades of white. I settled on white/light blue/silvery sparkle. Due to the low angle of the sun, the tiniest rough edge the size and shape of a pebble on the ground’s textured surface left a long, dark shadow.
Albedo is part of what has stabilized Earth’s climate for millennia, because under normal conditions, the white of the polar ice reflects light energy back to space, keeping average global temperature stable. It was the extraordinarily low angle of the sunlight that bounced right off the stunning bright whiteness of the ice. The sunlight was not absorbed by the ice and snow and instead was reflected away. And although the sun would never be directly overhead up here, it would be high enough to begin melting the ice.
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I ‘d been wondering why the meter-thick sea ice hadn’t yet begun to melt. Even though it was the end of March, even though the equinox had passed, the sun was out and the days were getting longer. On March 23, just three days after the equinox, we were already having 14-hour days with sunsets lasting past 9 p.m. That’s because in these high latitudes, the day length can increase by as much as 40 minutes per day.
As we turned around to go, I was struck in the face by the sun’s rays reflecting off the ice-covered ground. The brightness was astounding. And in that instant the meaning of “albedo” was seared into my brain in a way that went beyond reading about the science or looking at animations and illustrations.
It was the extraordinarily low angle of the sunlight that bounced right off the stunning bright whiteness of the ice. And although the sun would never be directly overhead up here, it would be high enough to begin melting the ice.
No matter how much a person studies Greenland, or the northern latitudes, or albedo, or Earth in general, going into the field to experience those things can change your entire understanding of the world and how it works. I stood there for a moment, just allowing the high-latitude sun’s cold rays to glance off the snowy ice and shine straight into my face.
NASA’s Oceans Melting Greenland (OMG) team is here in Greenland; here to find out specifically how much ice the island is losing due to warmer ocean waters around the coastline. There is almost no ocean data in remote places like this, but OMG is busy working to change that, studying the complex ocean processes that affect Greenland’s coastline because gathering data is critical to understanding Earth’s complex climate. This information will help us understand the amount of sea level rise we’re going to have around the world.
It was 11:30 in the morning and instrument engineer Jase Mickelin and I were in northern Greenland at the Thule Air Base pier looking over the frozen Salamanca Bay. And even though over the past week we ‘d somehow gotten used to the cold and I was wearing a big parka, my legs were starting to get cold after walking for an hour.
NASA’s Oceans Melting Greenland (OMG) team is here in Greenland; here to find out specifically how much ice the island is losing due to warmer ocean waters around the coastline.
The sun sits low in the sky even during midday. This iceberg calved off one of Greenland’s coastal glaciers, floated into the Fjord and then became trapped in sea ice.
Just the other day in fact, a group of us walked about 3 miles (5 kilometers) across the frozen ocean into the middle of the Fjord to visit icebergs trapped in the frozen seawater. We hadn’t worried at all about breaking through.
Why, with all this extra sunshine, was the sea surface still so frozen? And why did that hard, dry, crusty mixture of ice and snow still remain on the ground?
There was something special about the experience of having the rays of the sun, which was sitting low in the high latitude sky, hit the ice surface at that extremely low angle and reflect off into my eyes.
Low on the horizon.
Albedo is a measure of how reflective a surface is, how much light energy bounces off and reflects away and how much light energy gets absorbed. (Think hot asphalt on a sunny day. Black asphalt has a low albedo and absorbs light energy, while the brightest white has the highest albedo and reflects the light.).
By mid-April the meter-thick layer of frozen seawater that covers the sea surface and fills the fjords will completely melt and expose the dark blue ocean underneath. Today, even in this brilliant sunshine, even on this day of 14-hour sunlight, the ocean was still completely frozen over.
No matter where we were or how we stood or what time of day, all day, every day, there were always long shadows– crazy long shadows. I know that seems unbelievable, but even during the summer solstice, when Earth’s North Pole is tilted toward the sun, or during the four summer months of 24-hour daylight, the sun is always low, low, low at this latitude.