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Arctic Sea Ice Cover and Extreme Weather Explained

Posted on September 19, 2012 by Andreas Muenchow | Leave a comment

Addendum Sept.-24, 2012: A New Climate State, Arctic Sea Ice 2012 (video by Peter Sinclair).

I just discovered an outstanding interview that Dr. Jennifer Francis of Rutgers University gave to a non-profit community radio station out of Vancouver, British Columbia.

Jennifer Francis Interview 20120910

She connects and explains global warming, its much amplified signal in the Arctic, the extreme record minimal Arctic sea ice cover this summer, and how the warming Arctic and its disappearing sea ice impacts our weather in the northern hemisphere by slowing down the atmospheric jet stream separating polar from mid-latitude air masses. She explains all of this in non-technical language without loss of accuracy.

Dr. Jennifer Francis, Rutgers University [Photo Credit: ARCUS]

If this program piques your interest and you want to read more, Andrew Revkin of the New York time has led an informed discussion at his New York Times blog Dot Earth. And finally, Climate Central presented and illustrated Dr. Francis’ observations and ideas rather well with graphics and videos.

The Canadian Coast Guard Ship is powered by such a diverse and talented group of women and men from Newfoundland, Labrador, and beyond, that one or even two posts here hardly do justice to describe how well they run their ship and its many facilities that many mid-sized cities do not have. Monday I wrote about the people who run the power plant and electric departments as well as the seamen who fight fires and run fishing fleet and port facilities. Today I want to show the airport and talk a little about the civil administration that oversees and manages all aboard the ship.

Landing deck of the CCGS Henry Larsen with aircraft preparing for take-off to survey the ice conditions ahead. Shown are Chief Officer Brian Legge (far right) who is in command of the airport and is talking to Pilot Don Dobbin (2nd from right), scientist Renske Gelderloos (3rd from right), Ice Services Specialist Erin Clarke (4th from right), and Helicopter Engineer Pierre Autran performs last checks inside the helicopter. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

The airport consists of hangar, landing pad, helicopter, traffic control, and fire fighting stations. Don Dobbin was our pilot and Pierre Autran his engineer who was pulled out of retirement for this trip. Incidentally, Pierre and I had sailed together on the same ship in 1993 more than 200 miles north of eastern Siberia. Then all flights were prohibited by Russian aviation authorities: Politics were different 20 years ago, one hopes. No such threat of being shot down existed this year between Greenland and Canada, but for severe ice conditions and poor internet connections, the airport was very busy almost every day for both ice surveys ahead and behind the ship. It also supported landing parties to set up and/or service 4 weather stations.

Helicopter pilot Don Dobbin with scientist Dave Riedel on Hans Island servicing a weather station in the center of Nares Strait. Ellesmere Island in the background. [Photo Credit: Allison Einolf, Minnesota]

The air traffic control takes place both on the flight deck where Chief Officer Brian Legge is in charge and from the bridge where the officer-of-the-deck is in overall command as either First Officer Chris Steward or Second Officer Rebecca Acton-Bond place the ship, alert the entire ship, and often oversee other science operations as well. All of these are demanding jobs, all these jobs need precision in the concise communication of orders and permissions granted or denied as well as execution of all operations, because helicopter operations are probably one of the most dangerous and critical operations possible on the ship.

Attention to detail, clear communication, and calm execution lower the risk of death and destruction that helicopters can and often do cause. The National Science Foundation sent me to a 4-day course in helicopter safety and what to do if accidents happen over water or on land. It was a sobering course. For this reason, perhaps, Captain Wayne Duffett is almost always on the deck during flight operations, but as all good chief executives, he lets his officers and navigators run the operations but is available for help on consultation should it be needed.

Second Officer and navigator Rebecca Acton-Bond on a sunday on the bridge of the CCGS Henry Larsen in August of 2012 in Nares Strait. [Photo Credit: Canadian Coast Guard, Kirk McNeil, Labrador]

Leading Seaman and helmsman Melvin Cobb on the bridge. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

The navigator always works with a helmsman or quartermaster who steers the ship following instructions of the officer of the deck, they are on the look-out for ice and bergs to find the best routes. “Best” here refers to the route that requires the least amount of ice breaking. So, if there is one thing that icebreakers like the Larsen are really good at, it is how to avoid ice, because it is a violent and high-energy activity. Fuel is not cheap and less ice is broken, the faster and more efficient the tasks at hand can be accomplished.

And as all people on the ship, everyone has more than one job and this includes the helmsmen and quartermasters like Melvin Cobb or firefighters like Derick Stone, Carl Rose, Paul Gillingham, and Rueben Hillier. They are often members of the deck crew that help landing parties to get ashore and stay save while ashore. This involves the zodiac as well as guns to protect from polar bears:

Seamen Paul Gillingham and Rueben Hillier in the zodiac steered by Chief Officer Brian Legge in Alexandra Fjord, Ellesmere Island on Aug.-13, 2012. A tide gauge was recovered and re-deployed near this site. [Photo Credit: Canadian Coast Ship Henry Larsen, Barbara O'Connell]

Zodiac launched for a landing part to dismantle a weather station at Cape Baird, Ellesmere Island. Chief Officer Brian Legge at the helm with Melvin Cobb and Derick Stone in the back and center left of the boat filled with scientists Humfrey Melling, David Riedel, Andreas Muenchow, and Renske Geldeloos. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

Landing party at Cape Baird, Ellesmere Island to dismantle a weather station. Scientists David Riedel (foreground) and Humfrey Melling (background) are protected by Melvin Cobb (with gun) from polar bears. View is towards the north-west across Lady Franklin Bay to the west of Nares Strait. [Photo Credit: Renske Gelderloos, Oxford University]

Taking down a weather station on Cape Baird, Ellesmere Island, view is to the south-west. People from right to left, the author, David Riedel (kneeling), Melvin Cobb, and Humfrey Melling (covered). [Photo Credit: Renske Gelderloos, Oxford University]

Polar bear on an ice floe in Kennedy Channel as seen from the bridge as the ship was approaching a station a day’s polar bear walk from Cape Baird. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

There is still more to describe such as the hospital, the restaurant and bar, as well as the superior fishing of sailors and fishermen from Newfoundland to find and hook valuable items such as sensors and computers that some scientists left unattended for 3 or 5 or 9 years at the bottom of the unspoiled seas that border Arctic Greenland and Canada. There will be more … as there are more great people who make great science possible.

The Canadian Coast Guard Ship Henry Larsen sailed this summer on a challenging science mission to Nares Strait, Petermann Glacier, and beyond. It reached its farthest North ever at 82 degrees and 15 minutes North latitude. This week I like to focus on the 39 people who make this ship what it really is: a complex community with all the functionality of a city. Captain Wayne Duffett is in overall command. His job will overwhelm lesser minds as he has to manage an airport, a fire department, a power plant, a sanitation department, a hospital, a restaurant, a hotel, a supermarket, a weather station, a port facility, a civil administration, etc., etc. Oh yeah, The CCGS Henry Larsen is also a ship that he moves through ice in uncharted waters to support 8 scientists from 3 countries. All of this is done with only 22 crew and 17 officers who work around the clock on a variety of schedules.

CCGS Henry Larsen next to the Petermann Ice Island PII-2012 on Aug.-10, 2012. The south-western tip of PII-2012 at the bottom right of the image was used by Captain Wayne Duffett as a reference point for the motion of PII-2012. The exact place of this point was monitored at hourly intervals via helicopter while the ship was operating inside the fjord landward of the ice island. [Photo Credit: Canadian Coast Guard Ship Henry Larsen/Jo Poole]

Canadian Coast Guard Ship Henry Larsen at the entrance to Petermann Fjord on Aug.-10, 2012. The ice island PII-2012 is in the background with puddles on sea ice in the foreground. Polaris Bay, Greenland is in the far back. [Photo Credit: CCGS Henry Larsen and Jo Poole.]

The ship may occupy an area of only 2,000 m^2 (100 meters long and 20 meters wide), but it functions as a self-contained universe at sea. Perhaps the most important and largest department with 13 people is the power plant that produces energy to move the ship and to provide electricity and heat to make all other departments’ work possible. The 13 members are quiet and thoughtful men often working in the background in cramped, hot, and dirty spaces below decks. It is very hard to get good pictures of them, but here are two, one of Chief Engineer William Derraugh and Second Electrical Officer Anatoly Eltsov:

Chief Engineer William Derraugh on the bridge of the CCGS Henry Larsen in Aug.-2012 with Senior Scientist Dr. Humfrey Melling. [Photo Credit: Barb O'Connell, Canadian Coast Guard.]

Electrical Officer Anatoly Eltsov during a thoughtful moment on the bridge of the Canadian Coast Ship Henry Larsen in Nares Strait. [Photo Credit: Kirk McNeil, Canadian Coast Guard]

The second-largest department is the fire department that also run the port facilities, the fishing fleet, and provide general support on deck, on the bridge, on the water, and on land to a range of activities. There are nine men in this department that are led by the boatswain or bosun Don Barnable with Chief Officer Brian Legge in command. The men of this department are perhaps the most vocal and visible on the ship as they work so many jobs wearing many hats, uniforms, and arms. I can and will fill entire picture galleries of their work, here are just three images that barely serve as teasers, perhaps:

Boatswain Don Barnable and Seaman Derick Stone working at the airport aboard the CCGS Henry Larsen as traffic control and fire fighter, respectively. [Photo Credit: Jo Poole, British Columbia]

Zodiac of the CCGS Henry Larsen recovering a mooring in Kennedy Channel on Aug.-6 with Chief Officer Brian Legge at the helm. Ellesmere Island, Canada is in the background. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

Deck crew of CCGS Henry Larsen led by boatswain Don Barnable (white helmet) recovering a mooring over the side where the zodiac delivered it to the crane. Two scientists in the background waiting for the deck to be secure. [Photo Credit: Canadian Coast Guard Ship Henry Larsen]

I will have to stop here for now, and will report tomorrow and thursday about the logistics, communication, aviation, hospital, and civil administration departments. There is just too much going on aboard a ship that acts like a complex, advanced, and very mobile city. And with mobile I do not just mean a structure of steel, but a structure made of sailors, navigators, scientists, and engineers.

Dr. Preben Gudmandsen pioneered some of the early micro-wave remote sensors 30-40 years ago that are now used routinely to monitor sea ice, snow, and glaciers. Despite being “retired” for over 20 years, this Danish professor of Electrical Engineering is still very active in all things related to Nares Strait from sea ice, oceanography, glaciers, and winds. He is one of the main instigators to set up the automated weather station at Hans Island.

Nares Strait bottom depth (in meters) according to the International Bathymetric Chart of the Arctic Ocean (IBCAO, version 2, 2008). The black dot in the center of Nares Strait indicates Hans Island.

He also instigated the latest round of exchanges among “Friends of Nares Strait” about the fate of the ice island that broke off earlier this summer from Petermann Gletscher. He asked yesterday what may happen if PII-2012 reaches the sill separating northern Nares Strait and the Arctic Ocean from southern Nares Strait and the Atlantic Ocean. This sill is the deepest connection between the Arctic Ocean to the north and Baffin Bay in the south. The sill is in western Kane Basin off Ellesmere island and is about 220 meters deep.

So, to answer that question one needs to know three things: Where is the ice island, how deep is the water where it is, and how thick is the ice island. Before I could assemble these three things, however, the ice island has already broken into at least three pieces. Luc Desjardins of the Canadian Ice Service answered first by pointing this out. He has access to the commercial RadarSat data that few others have. So, here is the latest from MODIS which answers the first two questions:

Petermann ice island 2012 (PII-2012) breaking apart on Sept.-1, 2012 near the sill of Nares Strait. Faint black lines are bottom contours of 200, 150, 100, and 50 meter depth (IBCAO-2). Bottom left has clouds, top right is the mountainous terrain of Ellesmere Island. The most southerly part of PII-2012 is the thickest as it was attached to the glacier earlier this year. The most northerly section connected to PII-2010 which passed a moored array in place near Hans Island on Sept.-22, 2010.

Petermann Ice Island 2012 as one piece on Aug.-30, 2012 19:20 UTC in Kane Basin over contours of bottom topography.

From the above two MODIS images over contours of bottom topography, the shallowest water that PII-2012 has seen is the 150-m contour to the east towards Greenland. It is possible, however, that PII-2012 may also have hit some shallow topographic feature not properly charted in IBCAO-2008 (there is a 2012 version, I just learnt) or not properly contoured by me. Lets move on the next question, how thick is this ice island?

From data we recovered 3 weeks ago I can say, however, that PII-2012 is thicker than 144 meters. I base this estimate on the ice island that formed in 2010 and that passed over our moored array on Sept.-22, 2010. It hit two ice profiling sonars at 75 meters and damaged the stainless steel guard cage designed to protect the sensors (which they did), e.g.,

Two Ice Profiling Sonars (IPS) aboard the CCGS Henry Larsen in Aug.-2012. The bent stainless steel protective frame was bent by the 2010 ice island that hit both instruments in Sept.-2010. [Photo Credit: Andreas Muenchow]

Another instrument moored deeper at ~360 meter depth sends out acoustic pings and measures how much sound comes back. A weak scatter like some microscopic plankton or grain of mud or sand in the water reflects little energy, but a hard surface like the ice floating atop reflects lots. And here is how a time series of this backscattered energy looks like when an ice island passes over:

A 24-hour segment of acoustic backscatter from a bottom-mounted acoustic Doppler current profiler is show to vary with time and height above the bottom. The dark red represents the sea surface and/or the bottom of ice floating on it. Vertical resolution is 8 meters, temporal resolution is 30 minutes for a 3-year deployment. The main purpose of this instrument is to measure ocean currents at the same spatial and temporal resolution as shown here for backscatter. PII-2012-B passed over the instrument on Sept.-22, 2010 and is here estimated to be about 144 meters thick.

The exact place of the mooring and the time that PII-2010-B was on Sept.-22, 2010 is shown in this MODIS image of that day:

Location of ADCP mooring site (red square) with Petermann Ice Island 2010 segment B overhead on Sept.-22, 2010.

If you like puzzles, then you will like physical oceanography or any field of science or engineering. If you like puzzles, you will correctly notice, that the flat segment of PII-2010-B oriented parallel to the shores of Ellesmere Island fits the flat segment of PII-2012 that also has a hook to the north. These two segments were indeed connected before they separated from the glacier in 2010 and 2012. This is the reason, that the thickest part of the 2010 ice island is the shallowest part of the 2012 ice island, because the ice gets thicker towards the grounding line of Petermann Gletscher.

And finally, if you like puzzles, then you should consider a care

Arctic Sea Ice Cover and Extreme Weather Explained

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