Feature: Arctic Thaw

Measuring Change

The ‘Glory’ in Clouds and Other Amazing Sights!

by | 5.24.2012 at 4:04pm
Follow us on Facebook or Twitter

If you look carefully at the picture below you will see a small shadow of our plane completely encircled in a rainbow. This optical phenomenon, called a “glory,” can develop when the plane flies directly between the sun and a cloud below. Flying over the ice sheet in the far northeast of Greenland we saw this “glory,” the result of refracted water in the clouds appearing like a rainbow-colored halo when the observer is directly between the sun and cloud of refracting water droplets. Because our ATM laser and the DMS cameras rely on there being no clouds beneath us as they collect data, we don’t often see “glories.” The light cloud cover seen here doesn’t bother the instruments much – we can still see through it – so we get data and “glory” – a win-win situation.

The optical phenomenon called a "glory" can develop when the plane flies directly between the sun and a cloud below.

The rocks peeking up through the misty cloud layer show evidence of fluvial drainage, where running water has cut through the rock. We have seen lots of evidence of running water in the north, both here and in the large, long drainage channels that ran over the surface of Humboldt Glacier in the northwest. Beneath these channels the geology in this northeast section of Greenland shows a more complicated relationship than we have seen elsewhere. Here we see alternating bands of lighter and darker brown in the rock face, unlike the more regular rock bedding we have seen in other regions.
Humboldt

Icebridge flew the Humboldt glacier for the first time this season. Humboldt, a very wide but slow-moving and slow-changing glacier, lies just to the west of Petermann Glacier at the very northern edge of Greenland. Most of the ice flow in Humboldt glacier is concentrated on its eastern margin, but the very wide calving front is very impressive.

Surface meltwater channels on Humboldt Glacier – this is just inland of the calving front – you can make out icebergs in the sea ice in front of the glacier at the top of the frame.

The eastern margin of Humboldt Glacier: Again you can see the icebergs out to sea. The scalloped edge marks the eastern boundary between rock and ice, and the rocks here are the same metasediments (sedimentary rocks that have experienced some metamorphism) that we see exposed in the cliffs on the margins of Petermann Glacier, which we have flown for the last two years, but didn’t get to this year.

Humboldt Glacier: You can see the very slightly dipping strata exposed in the side of this channel carved into the rock just off the side of Humboldt.

NW fjords
The northwest fjords flight was designed for the gravity team to survey just offshore, measuring the gravity signal of the sea bed to determine the geometry of the fjords. This information will assist modelers in investigating why the loss of ice mass in the area is increasing, and how ocean current might be involved.

Kong Oscar Glacier with all the ice and icebergs that have broken off floating in front. This broken ice debris in front of a glacier is called mélange.

We flew another mission in this area along the NW glaciers, flying up and down the axis of a dozen glaciers in this area to look at the bed structure with radar and changes in elevation over time using the ATM laser.

I got interested in the erosive power of the glaciers looking at sediment deposits coming off the valley walls. Sediment piles up at the bottom of cliffs

Sediment that piles up at the mouth of valleys has a delta-like appearance.

Glacial "trim line" shows where the glacier has been in the past.

Ellesmere Island
For the Ellesmere Island flight, I sat in the cockpit and we had a bit of everything. Ellesmere Island is the northernmost island in the Canadian Arctic, lying just west of Greenland in the Territory of Nunavut (Inuit for “our land”). The island is known as the home of the furthest north permanently inhabited place on Earth, Alert.

Beautiful clouds seen as we transited over Ellesmere Island.

I enjoyed this glacier because it appears to be sticking its tongue out as the ice has retreated up the valley wall over time.

And then exposed rock showing the variability of rock type in the area.

I was glad to have been on this flight, because it turned out to be our last one of the season (there were 43 data flights in total this year). Routine maintenance on the plane when we got back turned up a part that needed to be replaced, and the logistics of that are taking time. So we are waiting in Thule for the part to get here (there are only a couple of flights a week that it can come on). Once everything is operational again, we will be heading home. We’ve packed our cargo, backed up all the data, and now we are catching up on blogs and reports and all the desk work that wasn’t done on the plane. The current plan is to fly home on Friday – contingent on the part arriving on Thursday and everything going perfectly from there. In the meantime, I can look out the window and see fox and hare tracks in the snow.

Follow us on Facebook or Twitter

Comment Using Social Media

Comment