Tag Archives: oden

Preparing for Petermann One Day At a Time

Glaciers, Greenland, Adventure, Expedition, Ice, Polar Bears, Narwhales, oh the fun to go to Greenland.

Swedish icebreaker I/B Oden 22 July 2015 on its way to Thule. [Photo Credit: https://twitter.com/SjoV_isbrytning]

Swedish icebreaker I/B Oden 22 July 2015 on its way to Thule. [Photo Credit: https://twitter.com/SjoV_isbrytning%5D


This romantic notion is false and pretty pictures always lie. To prove my point, I just list what one scientist does 4 days before shipping out to Greenland for 5 weeks. [My wife left last week to visit our grown son in California. She knows the drill, focus, and strain that does not make good company. We have gone through such 4-8 weeks of separation many times during our 20+ years of marriage; her leaving a week before I do works rather well for us]:

04:45 Wake up
05:00 Check e-mail on iPhone in bed
05:05 Read Twitter feed: Canadian research ship diverted to break ice in Hudson Bay
05:10 Check references to outreach-related news
05:15 Read Wilson Quarterly article “The Race to the Arctic” on Arctic developments with global policy impacts
05:30 Shower and Dress
05:45 Check Iridium data collection to Oden, fix minor problem
06:00 Check Hans Island weather, winds still from the north at 10 kts
06:15 Clean up mess cat made, make coffee
06:30 Check latest satellite imagery on Nares Strait, beautiful Arctic lead (upwelling) and sediment plumes from streams and glaciers
07:00 Bicycling to work
07:15 Brief hallway meeting with new grant specialist
07:30 Checking news on Arctic Sea Ice Forums
07:35 Downloading and reading peer-reviewed papers for proposal writing
08:00 Distracted by Tamino’s post about Five signs of denial regarding climate change
08:00 NSF Proposal writing
08:30 Distracted, responding to international e-mails
09:00 Passing links and photos for future press release

My littered office with 2 (of 10) drums of cable to connect ocean sensors through 300 m thick ice to Iridium satellite phone at the surface.

My littered office with 2 (of 10) drums of cable to connect ocean sensors through 300 m thick ice to Iridium satellite phone at the surface.

I am falling behind and feel the tension to get this NSF proposal finished by saturday. NSF stands for National Science Foundation, the proposal is asking for $500,000 to conduct a 3-year experiment with German and Norwegian scientists in the summers of 2016 and 2017. If successful, it will support two graduate students full time for two (MS) and three (PhD) years as well as two technicians for five months total. Peer-review of these proposals is brutal with perhaps a 1:7 success rate on average.

09:15 NSF proposal writing
09:40 Respond to former collaborator on an underwater acoustic communication project
09:45 Back to NSF proposal writing
10:00 Studying Sutherland and Cenedese (2009) on dynamics of the East Greenland Current interacting with canyons as explored by laboratory study
10:30 Converting Latex files to .pdf for uploads to NSF server
11:00 Read and edit UDel Press Release
11:15 Giving university administrators full access to current version of NSF proposal after uploading files to NSF servers
11:20 Heading to coffee shop for short bicycle break
12:00 UNAVCO gear arrived at office
12:05 Re-design the mechanics of the surface mount of the automated weather station to be deployed on Petermann Glacier

UNAVCO GPS systems for deployment on Petermann Gletscher.

12:45 Checking ice and weather in Nares Strait, Arctic Forecast
13:00 Back to proposal, writing/thinking about buoyant coastal currents interacting with canyons
16:00 Meet with PhD student on physics of GPS
16:15 Back to proposal writing
17:30 Graphical layout of proposal
18:15 Bicycle to Main Street for steak + margarita dinner
19:30 Home; set-up overdue MODIS processing
19:45 Edit this list, add links, and photos
19:55 Check Nares Strait weather and DMI Greenland ice
20:15 Daily Iridium data download from Oden works (equipment testing)


20:30 Posting this post
20:45 Editing and updating this post
21:00 Finished processing and posting on my web serverNares Strait MODIS imagery for the week

Oceanography of Nares Strait Ice Flushing

I need the ice out of Nares Strait, a 20 mile wide and 300 miles long pathway to the North Pole between northern Canada and Greenland. The ice blocks our way to Petermann Fjord where a large glacier pushes thick ice out so sea as a floating ice shelf. We plan to drill through the floating section of the glacier that is about as thick as the Empire State Building is high. The ship to get us there is the Swedish icebreaker Oden (Location Map). She is passing the Faroe Islands to the north-west of Scotland and will arrive in 2 weeks at Thule Air Force Base where we will meet her.

Image of northern Greenland (top right) and Ellesmere Island (center) showing open water as black, land as gray, and sea ice as gray/white. The two red dots are Thule Air Force Base in the south and Petermann Glacier in the north. Note the bands of black water along the coast of Ellesmere Island that result from east to west blowing winds that move ice offshore.

Image of northern Greenland (top right) and Ellesmere Island (center) showing open water as black, land as gray, and sea ice as gray/white. The two red dots are Thule Air Force Base in the south and Petermann Glacier in the north. Note the bands of black water along the coast of Ellesmere Island that result from east to west blowing winds that move ice offshore and reduce the southward flow in Nares Strait.

The voyage from Thule to Petermann usually takes about 2-3 days, but if the sea ice does not flush out with the generally southward currents, then it may take a week or two wrecking havoc to our busy science schedule. So, why is the ice still lingering in Nares Strait this year?

Nares Strait ice cover in July of 2015 (left), 2014 (center), and 2013 (right) from MODIS Terra.

Nares Strait ice cover in July of 2015 (left), 2014 (center), and 2013 (right) from MODIS Terra.

There are three parts to the answer: First, a sturdy ice arch at the southern entrance of Nares Strait has to break. It has done so only last week. Second, a strong and perhaps oscillating flow has to thoroughly collapse the large pieces of ice at a narrow choke point that is Smith Sound. This has not happened yet. And third, a persistent flow to the south has to flush out ice into Baffin Bay to the south faster than it enters from the Arctic Ocean in the north. This flow is much weaker at the moment than is normal, because winds in the Arctic Ocean have been from east to west right now. These winds moved water (and ice) offshore to the north, so sealevel along northern Greenland and Canada drops. We can see this in today’s satellite imagery as prominent black bands of open water along the coast of northern Canada.

Lets take a closer look of this same image and zoom in on the southern part of Nares Strait as it looked this morning.

Collapsing ice arch at the southern entrance to Nares Strait on 13 July 2015 from MODIS AQUA.

Collapsing ice arch at the southern entrance to Nares Strait on 13 July 2015 from MODIS AQUA.

What used to be a solid frozen mass of ice along the Greenland coast (bottom right) has become a broken and loose mass of smaller ice floes. The larger blocks farther from the coast are now sliding southward as the loose ice along the coast reduces friction or lubricates the edges. The sides lose their grip on the ice and the entire construction fails and collapses. A most beautiful video on the stability of arches is posted by Open University here about lines of action or thrust.

All we now need for the ice to flush out of Nares Strait is a weakening or reversal of the winds at the other northern entrances to Nares Strait. Much of the generally southward flow is caused by the ocean’s surface being higher in the north than it is in the south. There are details that I am skipping, but basically much of the flow rolls downhill like a ball. And with the winds up north being from east to west, there is not much of a hill that the water can flow down, so we got somewhat stagnant waters. I have actually measured the height of this “hill of water” many times over the many years with ocean sensors that measure how much water is above them. This figure summarizes 3 years of data collected every 3 hours or so

Graph showing how water flow (called “volume flux”) varies with the steepness of the hill (called “pressure gradient”). The “hill” is at most 10 centimeters or 3 inches) high. [Adapted from Muenchow, 2015]

Now there is more to the “hill” story that is modified near the surface by the earth’s rotation in a fluid that has different densities at different depths. In a nutshell, the surface flow is 2-3 times as strong as the depth averaged flow. Furthermore, the surface flow on the Canadian side of Nares Strait is often twice as strong as that closer to Greenland, but all these spatial variations in flow actually help to smash large pieces of ice by moving and rotating them different sides of the same large piece of ice differently.

So, lets all hope that we get a few days of strong winds from the north flowing south, that should clear Nares Strait quickly before Oden arrives there in 2 weeks time. Those winds from the north not only flush out ice from Nares Strait, they also keep it nicely on one, the Canadian side. Earth rotation does wonderful and magical things to fluids such as water and air.

Muenchow, A, 2015: Volume and freshwater flux observations from Nares Strait to the west of Greenland at daily time scales from 2003 to 2009. J. Phys. Oceanogr., re-submitted July 2015, .pdf