Tag Archives: Nares Strait

Land-Fast Ice Cover off North Greenland: Will NASA bite?

Posted on May 17, 2013 by | 6 Comments

When a large outlet glacier of North Greenland (Petermann Gletscher) discharged an ice island four times the size of Manhattan in August of 2010, the United States’ Congress held formal inquiries on its cause within days of the event. Congressmen, scientists, and the global media speculated that this event and concurrent severe droughts in Russia and floods in Asia were tied to record-breaking air temperatures and global warming. Reviewing available data, Johnson et al. (2011) cautioned that most melting of floating ice shelves such as Petermann Gletscher is dominated by physical ocean processes below, not above the ice (Reeh, 2001, Rignot and Steffen, 2008). The National Journal asked me to write an essay to answer the question: “Is Climate Change Causing Wild Weather?” which I answered with a nerdy No, but …. Motivated by questions asked during the congressional hearing, I showed that waters in Petermann Fjord (a) originate from the Arctic Ocean to the north, (b) contain heat of Atlantic origin, and (c) have warmed significantly since 2003 (Muenchow et al., 2011).

Petermann Gletscher from MODIS Terra. Repeat NASA along-glacier flight tracks are shown in the left and middle panels. White line across the glacier are ICESat tracks. Thick black line across the glacier near y = 0 km is the grounding line location from Rignot and Steffen (2008). Dark areas within 2 km off the western wall are mountain shadows.

Petermann Gletscher from MODIS Terra. Repeat NASA along-glacier flight tracks are shown in the left and middle panels. White line across the glacier are ICESat tracks. Thick black line across the glacier near y = 0 km is the grounding line location from Rignot and Steffen (2008). Dark areas within 2 km off the western wall are mountain shadows.

When I reported here that the same glacier discharged yet another ice island in July 2012, this one “only” twice the size of Manhattan, I was not so sure anymore, that this was merely another extreme event caused by natural processes. Furthermore, only 4 weeks later I was aboard the CCGS Henry Larsen working in Petermann Fjord and Nares Strait to recover instruments that we had deployed in 2009. Witnessing dramatic change off North Greenland from my first visit in 2003 to my last in 2012, I will send NASA a proposal on monday. If suported, it would enable me to test the idea, that a changing sea ice cover off North Greenland over the last 30 years or so relates to the retreat and decay of glaciers north of 76 N latitude. Most of these glaciers connect the Greenland Ice Sheet to the ocean via floating ice shelves as does Petermann.

This is an image that shows land-fast ice in Nares Strait next to Petermann with the large ice-arch blocking all flow of ice to the south where we see open water or thin ice:

June-10, 2012 MODIS-Terra image showing location of moored array that was deployed in Aug. 2009 to be recovered in Aug. 2012.

June-10, 2012 MODIS-Terra image showing location of moored array that was deployed in Aug. 2009 and that we recovered in Aug. 2012.

Contrast the conditions in June 2012 above with in April of 2009 below. The southern ice-arch failed to form in 2009, there is much open water and loose, thin ice next to Petermann Fjord, but a northern ice-arch formed and prevented all flow of thick ice from the Arctic Ocean into Nares Strait or Petermann to glue it all together as it did in 2012 (or right now for that matter):

Largely ice-free Nares Strait on April 2009 with concurrent ocean velocity.

Largely ice-free Nares Strait on April 2009 with concurrent ocean velocity.

My main question is this: Has the changing sea ice cover next to glaciers anything to do with the break-up of many large glaciers all around North Greenland that we have observed the last few years? Is the removal of the summer sea ice from the many fjords of North Greenland a normal occurrence or is this a new regime that flushes many fjords free of ice in summer? Does the available record of air and ocean observations allow us to explain observed change? I believe that the public has all the data (MODIS, SSM/I, ICESat, etc) to answer these questions, but it will need a little work to actually provide quantifiable answers with error bars to pass academic peer review. Anyone is more than welcome to help and maybe even learn or apply skills for a graduate degree and well-paying jobs in physics or engineering.

ADDENDUM (16:33 EDT): As a result of Greenland losing so much mass and ice, the geographic North Pole started in 2005 to move abruptly towards Greenland. This was reported earlier this week by Nature after the research was accepted for publication at Geophys. Res. Let.

Johnson, H., Münchow, A., Falkner, K., & Melling, H. (2011). Ocean circulation and properties in Petermann Fjord, Greenland Journal of Geophysical Research, 116 (C1) DOI: 10.1029/2010JC006519

Münchow, A., Falkner, K., Melling, H., Rabe, B., & Johnson, H. (2011). Ocean Warming of Nares Strait Bottom Waters off Northwest Greenland, 2003–2009 Oceanography, 24 (3), 114-123 DOI: 10.5670/oceanog.2011.62

Reeh, N., H. H. Thomsen, A. K. Higgins, and A. Weidick (2001). Sea ice and the stability of north and northeast Greenland floating glaciers Annals of Glaciology, 33, 474-480

Rignot, E., & Steffen, K. (2008). Channelized bottom melting and stability of floating ice shelves Geophysical Research Letters, 35 (2) DOI: 10.1029/2007GL031765

→ 6 Comments

Posted in Global Warming, Greenland, Ice Cover, Ice Island, Petermann Glacier

Tagged , , , , , ,

Petermann Photos, Places, and People

Posted on May 2, 2013 by | 5 Comments

Petermann Gletscher sent off Manhattan-sized islands of ice in 2010 and 2012 that now litter the eastern seaboard of Canada from its farthest northern Ellesmere Island to its farthest eastern Newfoundland. The ice is streaming south along thousands of miles within icy Arctic waters. Petermann Gletscher itself is flat, hard to grasp by the naked eye, its endless expanse of white vanishes into the horizon when we look towards the Greenland Ice Sheet ALONG the glacier:

North-eastern section of Petermann Glacier on Aug.-11, 2012, the meandering river is the centerline, view is almost due east. [Photo Credit: Canadian Coast Guard Ship Henry Larsen.]

North-eastern portion of Petermann Glacier on Aug.-11, 2012, the meandering river is the centerline, view is almost due east with Kap Fulford and Kap Agnes on the left center and Daugaard Jensen Land in the background on the right. [Photo Credit: Canadian Coast Guard Ship Henry Larsen.]

Next, lets look ACROSS Petermann from roughly the same latitude. This perspective is more dramatic as vertical cliffs give shape, cliffs are cut by smaller side-glaciers. More specifically, we see the CCGS Henry Larsen helicopter flying down Belgrave Glacier as we look across Petermann which flows from the Greenland Ice Sheet on the left out to sea on the right. On the other (south-western) side we see Faith Glacier in the background about 10 miles away.

Seaward front of Petermann Glacier Aug.-11, 2012. View is from a small side-glacier towards the south-east across Petermann Fjord with Petermann Gletscher to the left (east). [Photo Credit: Erin Clarke, Canadian Coast Guard Ship Henry Larsen]

Seaward front of Petermann Glacier Aug.-11, 2012. View is from a small side-glacier (Belgrave Gl.) towards a similar glacier (Faith Gl.) across Petermann Fjord with Petermann Gletscher flowing from the left out to sea on the right. [Photo Credit: Erin Clarke, Canadian Coast Guard Ship Henry Larsen]

Contrasting large Petermann Gletscher, the many smaller glaciers on both its sides evoke drama as ice plunges down from 3000 feet above in a rage of forms, colors, and shapes. These side glaciers have their own side glaciers that sometimes rival the Alpine glaciers in Europe, Asia, and the Americas that most of us are more familiar with.

Some side glaciers have names, but they are rarely seen on maps and charts. The side glaciers are mapped, but photos are hard to find. Flying over them last year, I was utterly lost. Reviewing photos now, I remember people, smells, computer troubles, and exciting ocean discoveries. Nevertheless, I am hard pressed to place the places we saw on a map or name them. Distances are deceiving, the air is clean and 50-80 miles of visibility are common. A moment later, I cannot see the other side of the ship as we are suddenly in clouds and fog. Everything is always in motion, the ice, the water, the ship, the clouds, all of this without strong reference points like the exit or distance signs on a Turnpike, Interstate, or Autobahn.

Northern Kennedy Channel near the entrance to Petermann Fjord with Kap Morton in cloud banks. [Credit: Andreas Muenchow]

Northern Kennedy Channel near the entrance to Petermann Fjord with Kap Morton in cloud banks. [Credit: Andreas Muenchow]

And along comes Espen Olsen, a frequent contributor to Neven’s Arctic Sea Ice blog and forums, and discovers a plethora of names that I can check, google, and use to remember expeditions to Petermann over the last 10 years with many good friends. So with his help and that of other explorers like Lauge Koch, Tony Higgins, and the collected wisdom of the U.S. Defense Mapping Agency, I labeled some prominent glaciers and capes on an Aug,-21, 2012 MODIS-Terra image that I constructed from data that NASA provide to anyone free of charge. I chose this image and time, because the 2012 ice island is already in Nares Strait and thus out of sight:

Names of glaciers, capes, islands in Petermann Region over MODIS of Aug.-21, 2012.

Names of glaciers, capes, islands in Petermann Region over MODIS of Aug.-21, 2012.

Espen tells me that his Danish sources are protected by copyright (I still like to cite them), but the aviation maps of the U.S. military are in the public domain and can be downloaded from the University of Texas in Austin Library, e.g.,

Petermann Gletscher and surroundings extracted from U.S. Defense Mapping Agency Chart ONC A5 (January 1991).

Petermann Gletscher and suroundings extracted from U.S. Defense Mapping Agency Chart ONC A5 (January 1991).

while the modified version of Figure-2 from Dr. Tony Higgins 1990 publication is available at the Alfred Wegener Institute. Nevertheless, it should only be used for non-profit educational purposes or as a reference:

Petermann Gletscher extend and topography from 1953 through 1978 (from Higgins, 1990) with 2012 terminus position drawn in by hand.

Petermann Gletscher extend and topography from 1953 through 1978 (from Higgins, 1990) with 2012 terminus position drawn in by hand.

With all these details out-of-the-way, we can now start placing photos into places and add names to them. Perhaps others like Espen Olsen can write or edit Wiki entries or correct the false latitude and longitudes that populate the many databases that provide such information on the web. Over the next weeks and months I will try to post as many photos of Petermann’s natural beauty along with an evolving MODIS map that names and shows places. Here are just a few teasers without further comment except what’s in the captions.

The merging of Sigurd Berg and Hubert Glaciers which discharge into Petermann Gletscher on its eastern wall. The view is landward towards the north-east as the helicopter flies in from Petermann. [Credit: Barbara O'Connell, Canadian Coast Guard]

The merging of Hubert (left) and Sigurd Berg (right) Glaciers which discharge into Petermann Gletscher on its eastern wall. The view is landward towards the north-east as the helicopter flies in from Petermann. [Credit: Barbara O'Connell, Canadian Coast Guard]

Petermann Gletscher and Fjord in Aug.-2012. View is to the north-west with Faith Glacier (top left) and Kap Lucie Marie (top right) showing the western wall of Petermann. [Photo Credit: CCGS Henry Larsen]

Petermann Gletscher and Fjord in Aug.-2012. View is to the north-west with Faith Glacier (top left) and Kap Lucie Marie (top right) showing the western wall of Petermann. [Photo Credit: CCGS Henry Larsen]

Looking down Belgrave Glacier discharging into Petermann Gletscher at its terminus in Aug. 2012 [Credit: CCGS Henry Larsen]

Looking down Belgrave Glacier discharging into Petermann Gletscher at its terminus in Aug. 2012 [Credit: CCGS Henry Larsen]

Higgins, A.K. (1990). Northern Greenland glacier velocities and calf ice production Polarforschung, 60, 1-23 Other: 0032-2490

→ 5 Comments

Posted in Greenland, Ice Island, Nares Strait 2012, Petermann Glacier

Tagged , , , , , ,

Shades of White as the Sun Rises over Nares Strait

Posted on March 5, 2013 by | 5 Comments

After four months of total darkness the sun is back up in Nares Strait. It transforms the polar night into thousand shades of white as mountains, glaciers, and ice take in and throw back the new light. Our satellites receive some of the throw-away light as the landscape reflects it back into space. During the long dark winter months these satellites could only “see” heat, but this will change rapidly as Alert atop of Arctic Canada receives 30 minutes more sun with each passing day.

Surface temperature in degrees centigrade over northern Baffin Bay on March-4, 2013 16:20 UTC from MODIS Terra.

Surface temperature in degrees centigrade over northern Baffin Bay on March-4, 2013 16:20 UTC from MODIS Terra. Warm colors (reds) show thin and/or ice while cold colors (blues) suggest thick ice stuck in place.

A very strong ice arch at the southern entrance to Nares Strait separates thick (and cold) ice to north from thin (and warm) ice to the south. The thick and cold ice is not moving, it is stuck to land, but the ocean under the ice is moving fast from north to south. The ocean currents thus sweep the newly formed thin ice away to the south. This ice arch formed way back in early November just after the sun set for winter over Nares Strait.

Now that the sun is up, we can also “see” more structures in the ice by the amount of light reflected back to space. A very white surface reflects lots while a darker surface reflects less. We are looking at the many shades of white here … even though I color them in reds and blues:

Surface reflectance at 865 nm in northern Baffin Bay on March-4, 2013 16:20 UTC from MODIS Terra.

Surface reflectance at 865 nm in northern Baffin Bay on March-4, 2013 16:20 UTC from MODIS Terra. A true color image (which this is not) would show only white everywhere. Hence I show the very bright white as red and the less bright white as blue. This artificial enhancement makes patterns and structures more visible to the eye.

Zooming into the area where the ice arch separates thick ice to the north that is not moving from thin ice in the south that is swept away by ocean currents, I show this image at the highest possible resolution:

Surface reflectance at 865 nm at the southern entrance to Nares Strait on March-4, 2013. Contours are 200-m bottom depth showing PII2012 grounded at the north-eastern sector of the ice arch.

Surface reflectance at 865 nm at the southern entrance to Nares Strait on March-4, 2013. Contours are 200-m bottom depth showing PII2012 grounded at the north-eastern sector of the ice arch.

Note, however, that the sun is far to south and barely peeking over the horizon. This low sun angle shows up as shadows cast by mountains. And since the sun is still far to the south, the shadows cast are to the north. This “shadow” makes visible the ice island from Petermann Gletscher that anchors this ice arch as it is grounded. I labeled it PII2012 in the picture.

From laser measurements we know that the ice islands stands about 20 meter (or 60 feet) above the rest of the ice field. This height is enough to cast a visible shadow towards the north (slightly darker = less red) as well as a direct reflection off its vertical wall facing south (brighter = more red) towards the sun. At its thickest point, PII2012 is about 200 meters (~600 feet) thick. For this reason, I also show the 200-m bottom contour that moves largely from north to south along both Ellesmere Island, Canada on the left and Greenland on the right.

The sun brings great joy to all, especially those hardy souls who live in the far north. The sun’s rise also shows the delicate interplay of light and shadows that we can use to solve puzzles on how ice, oceans, and glaciers work. At the entrance of Nares Strait the playful delights of the sea ice, ocean currents, and ice islands gives us a large area of thin ice. The thin ice will soon melt and perhaps has already started to set into motion a spring bloom of ocean plants. Ocean critters will feed on these to start another cycle of life. Whales, seals, and polar bears all depend on it for 1000s of years now.

Sketch of the biological pieces that a large area of open water near a fixed ice edge like that of a polynya may support. [From Northern Journal>/a>]

Sketch of the biological pieces that a large area of open water near a fixed ice edge like that of a polynya may support. [From Northern Journal]

→ 5 Comments

Posted in Ice Arch, Ice Cover, Ice Island, Oceanography, Uncategorized

Tagged , , , ,

Did I ever see a Polar Bear?

Posted on February 9, 2013 by | 2 Comments

When people hear that I have worked as a physical oceanographer in the Arctic for almost 20 years, their first question is often: “Did you ever see a Polar Bear?” The answer is a yes, but when we see bears, it is usually as a tiny moving speck of yellowish white near the white, icy, and hazy horizon. Only twice was it different. The first time was in October 2003 to the north-west off Arctic Alaska when a young bear swam towards and around the U.S. Coast Guard Cutter Healy doing station work:

Polar Bear seen Oct.-10, 2003 from aboard the USCGS Healy to the north-east of Alaska [Credit: Andreas Muenchow, University of Delawarel]

Polar Bear seen Oct.-10, 2003 from aboard the USCGC Healy to the north-east of Alaska [Credit: Andreas Muenchow, University of Delaware]

The second close encounter was last year as the Canadian Coast Guard Ship Henry Larsen was about to leave Nares Strait on Aug.-12. Out of the 100+ pictures snapped of this bear, the ship’s Steward Kirk McNeil of Labrador probably took the best shot:

Polar bear as seen in Kennedy Channel on Aug.-12, 2012. [Photo Credit: Kirk McNeil, Labrador from aboard the Canadian Coast Guard Ship Henry Larsen]

Polar bear as seen in Kennedy Channel on Aug.-12, 2012. [Photo Credit: Kirk McNeil, Labrador from aboard the Canadian Coast Guard Ship Henry Larsen]

This bear approached the drifting ship leisurely over a 10 minutes period from a large piece of ice that also drifted with the tides and currents. My PhD student Pat Ryan captured the last 2 minutes of this visit with her iPhone. The voice is hers (I also discern the voice of Ice Specialist Erin Clarke). Greenland is in the background to the east:

ADDENDUM Feb.-13, 2013: I just found this map of the spatial distribution of polar bears from a Dec.-23, 2012 article in the Washington Post by Juliet Eilperin entitled “Polar bear trade, hunting spark controversy.” Writing for the Wall Street Journal Feb.9, 2013, Zac Unger commented with the question “Are polar bears really disappearing?”

Polar bear population and their trends. [Source: Polar Bear Specialist Group. Laris Karklis/The Washington Post. Published on December 23, 2012, 5:24 p.m.]

Polar bear population and their trends. [Source: Polar Bear Specialist Group. Laris Karklis/The Washington Post. Published on December 23, 2012, 5:24 p.m.]

Addendum Feb.-25, 2013: A very funny bear commercial.

→ 2 Comments

Posted in Ice Cover, Nares Strait 2012, Wild Life

Tagged , , ,

Nares Strait Ice Arches and Petermann Ice Island 2012

Posted on November 13, 2012 by | 2 Comments

Arching barriers of ice locked solidly to land are presently closing off Nares Strait for all ice leaving or entering this ocean passage from the Arctic to the North Atlantic Oceans. Gothic cathedrals have flying buttressing to hold them in place while ice arches have buttressing land that keeps them stable. The sea ice becomes land-fast until these ice arches collapse in June or early July. As the ocean under the ice is still moving, generally from north to south, one often finds very thin ice or even open water to the immediate south of these ice arches. Some of these temperature signals let us “see” large ice structures even in the dark of night which in Nares Strait lasts from early October to late March.

Surface temperature in degrees Celsius for Nares Strait on Nov.-10, 2012 from MODIS Terra. Thick ice is blue (cold) while thin ice is red (warm).

Surface temperature at the northern entrances to Nares Strait with the Arctic Ocean to the north.

Surface temperature at the southern entrance of Nares Strait with the North Atlantic Ocean to the south.

Southern entrance of Nares Strait as seen from RADARSAT showing ice arch formation in more spatial detail than MODIS temperatures do. Note the embedded ice island PII-2012 from Petermann Gletscher at the north-eastern edge of the ice arch. [Credit: Luc Desjardins, Canadian Ice Service]

These ice arches usually form in December or January, but this year they form a little earlier than usual. In some years such as 2006/07 or 2009/10 and 2010/11 they did not form at all and thick multi-year ice left the Arctic via a passage that is now closed. This leaves only Fram Strait to the east of Greenland for such export this year.

It appears that the large ice island that broke free from Petermann Gletscher earlier this year provides some stabilizing support to the southern ice arch as it is anchoring its north-eastern corner where it is possibly grounded. The depth of the ice island PII-2012-A1 is about 180 to 200 meters thick. I derived this estimate from both NASA’s Airborne Topographic Mapper (ATM) and the University of Kansas’s Radar Depth Sounder both flown concurrently on a DC-8 plane that surveyed Petermann Gletscher on May-7, 2011 with PII-2012-A1 still attached:

Profile of Petermann Glacier from laser (red) and radar (black) measurements on May-07, 2011. The 2012 break-up is indicated by a spike of the red under-ice topography near km-22. Bottom profiles from laser assume hydrostatic balance of floating ice.

The ATM is a scanning laser that measures the distance from the DC-8 to the surface within 0.2 meters (about 6-7 inches). If I know both the true sea level surface (I do, it’s called the geoid) and if the ice is floating undisturbed, then I can convert the surface elevation into a bottom draft. The red curve outlines the “theoretical” bottom of the glacier. This curve is masked by a thicker black curve that is a radar-derived image of the under-side of the glacier. Nothing theoretical about that one. These radar measurements agree closely with the red curves indicating an almost perfectly balanced floating glacier. This “balance” breaks down at two important points: (1) Near -20 km the glacier bottom is shallower than the red draft curve and it is here that the glacier sits on land as it is not floating. (2) Near +22 km we see a large red spike. This is the location of the 2012 break-up.

So, the 2012 ice-island that is anchoring the ice arch in southern Nares Strait is the piece of the glacier to the right of the red spike and with these data I can now conclude that PII-2012 was 11 km long, 15 km wide, and about 200 m deep. This Manhattan-sized ice-cube weights about 30 gigatons (10^12 kg), but “… that doesn’t mean much — who goes to the store and buys a gigaton of carrots? For a sense of perspective, a gigaton is about twice the mass of all people on earth …” [James Fallows writing for The Atlantic]. Hence this little ice-cube weights 50 times as much as do all people living on earth today. Incidentally, it is also the amount of CO2 that all humanity adds each year to the atmosphere. Coincidence.

Front of Petermann Glacier Aug.-11, 2012. View is from a small side-glacier towards the south-east across Petermann Fjord with Petermann Gletscher to the left (east). [Photo Credit: Erin Clark, Canadian Coast Guard Ship Henry Larsen]

→ 2 Comments

Posted in Ice Arch, Ice Cover, Petermann Glacier

Tagged , , ,

Petermann and Ryder Glacier Ice Island

Posted on October 22, 2012 by | 5 Comments

Ice island from 2010 and 2012 calvings litter Nares Strait and northern Baffin Island, Canada. All these glacier fragments originate from Petermann and Ryder Gletscher in north-west Greenland. The image below is a composite that Luc Desjardins of the Canadian Ice Service compiled from RadarSat imagery. He painstakingly identified 25 segments in these imagery.

Ice Islands and fragments from Petermann and Ryder glacier 2010 and 2012 calvings. [Credit: Luc Desjardings, Canadian Ice Service]

The largest piece is PII-2012-A1 and it covers an area a little less than 2 Manhattans (100 km^2). We see it in Kane Basin for several weeks now as it pivots back and forth with the tides around the point where it is stuck to the bottom of the ocean. The second largest piece is RII-2012 roughly half the size of Manhattan (33 km^2) and it originates from Ryder Gletscher which is to the north by north-east of Petermann Gletscher. Trudy Wohleben identified this piece when it was entered Nares Strait from the north about 4 weeks ago and together we traced it back to Ryder Gletscher where it had lingered for several years. RII-2012 is now moving rapidly south and is about exit Nares Strait to enter Baffin Bay:

Two of these ice island send their position several time each day with the data made available at for PII-2010-B-a (9 km^2) and for PII-2012-A2 (13 km^2). The last piece broke off from Petermann on July 16, 2012 and it entered Nares Strait in August when we passed it during our explorations of Petermann Fjord on Aug. 10/11, 2012 aboard the CCGS Henry Larsen:

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.]

→ 5 Comments

Posted in Ice Island, Petermann Glacier

Tagged , , , , , ,

CCGS Henry Larsen: More on People, Places, and Services

Posted on September 13, 2012 by | 2 Comments

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.

→ 2 Comments

Posted in Nares Strait 2012, Polar Exploration

Tagged , , , ,

CCGS Henry Larsen: People, Places, Services

Posted on September 10, 2012 by | Leave a comment

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.

→ Leave a comment

Posted in Ice Island, Nares Strait 2012, Polar Exploration

Tagged , , ,

Petermann Ice Island 2012 Breaking Up

Posted on September 2, 2012 by | 4 Comments

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 career in physical oceanography or physics or mathematics or electrical or mechanical or civil engineering. These are fields where jobs and careers are plentiful and people live long and happy lives: Preben chose Electrical Engineering 70 years ago in Denmark, I chose physical oceanography 30 years ago in Germany, and Allison chose physics 3 years ago in the U.S. of A. Sadly, few American students chose to compete for these jobs and lives, because they need to take a “difficult” undergraduate major. Allison did, she picked physics and oceanography, and so can you.

University of Delaware summer intern Allison Einolf from Macalester College, Minnesota in Nares Strait in Aug.-2012 aboard CCGS Henry Larsen. Allison studies physics. [Photo Credit: Jo Poole, British Columbia]

→ 4 Comments

Posted in Ice Island, Nares Strait 2012, Oceanography, Petermann Glacier

Tagged , , , , , ,

Ice Thickness in Nares Strait 2008 and 2009

Posted on August 28, 2012 by | 1 Comment

[Editor's Note: Undergraduate Julie Jones of the University of Delaware summarizes her work that was supervised by Helga Huntley as part of an NSF-funded summer internship.]

Three years ago in 2009 Andreas Muenchow left from Delaware for Greenland with students Pat Ryan and Berit Rabe to recover instruments that recorded salinity, temperature, current velocities, and ice thickness in Nares Strait since 2007.  This summer, I used those observations to estimate ice thickness for April through June in 2008 and compare them to estimates for the same spring period in 2009.  An ice bridge had formed in 2008 but not in 2009.  Working as a group, we wanted to investigate the effect of ice arches on the ice thickness.  Allison Einolf, another summer intern who focused on ocean currents during the same time periods and Andreas produced these maps that introduce the study area, spatial ice cover, and mean ocean currents:

Image

Nares Strait MODIS satellite imagery of the study area and ice arch April 21, 2008. Red dots are instrument locations. Arrows show current velocities.

Image

Nares Strait MODIS satellite imagery of the study area and ice arch April 22, 2009. Red dots are instrument locations. Arrows show current velocities. Note the lack of the southern ice arch, but the presence of one north of the study area.

I used Matlab for most of the data processing, more specifically the Ice Profiling Sonar (IPS) Processing Toolbox for Matlab provided by the manufacturer of the instrument that collected the data: ASL Environmental Sciences, Inc. First I transformed the data from the IPS instrument into a range time series.  I then manually “despiked” the data, taking out any data points that were likely due to bubbles or fish within the acoustic path from the sensor system to the ice above and back.  In a second step I wrote a function using sound speed data from Andreas, atmospheric pressure from Dr. Samelson at Oregon State University, and pressure (depth) data from the IPS instrument to get a time series of the thickness of the ice.  In a third step I applied a Lanczos raised cosine filter that was taught as part of a 2012 Summer Intern Page Workshop. Hence I finally had some nicely filtered data for the periods of the April-June of 2008 and 2009.

Now the results:  Just as we expected, there was much thicker ice in the 2008 spring with a southern ice arch present than there was in the spring of 2009 when no such ice arch was present:

Histogram for April – June 2008 ice. There is a peak at 3 meters, with almost 25% of the ice that thick.

Histogram for April – June 2009 ice. The ice does not get thicker then 2 meters with most of the ice thinner than one meter.

The histograms show thicker ice in 2008, about 2-6 meters on average and with some ice even reaching 10 meters.  In 2009, the ice doesn’t get thicker than 2 meters with most of the ice being thinner than 1 meter.  More specifically, the mean ice thickness for April – June 2008 (2009) is 3.8 (0.58) meters with a standard deviation of 1.8 (0.29) meters.  This further shows that there was thicker ice in 2008 than there was in 2009.  I attributed the cause for the thin 2009 ice to ice flowing freely through Nares Strait all winter and spring as no ice arch in the south blocked such flow.  The ice, thus, did not spend enough time in the high Arctic to thicken.

I noticed something else in my histograms when the 2008 ice bridge collapsed.

April 2008 ice thickness

May 2008 ice thickness

June 2008 Ice Thickness

The monthly histograms show that the ice in April and May is thicker than the ice in June.  We know that the 2008 ice bridge collapsed near June 6th, so it is interesting and it makes a lot of sense that the ice in June would be thinner than the ice two months earlier.

The mean ice thickness for April 2008 was 4.6 meters with a standard deviation of 2.40 meters.  In May 2008 the mean ice thickness was 3.5 meters with a standard deviation of 1.40 meters.  Lastly, in June the mean ice thickness was 3.5 meters with a standard deviation of 1.30 meters.  The ice thickness decreased after April and the variability decreases in June, which helps detect the bridge collapse in the data.

Lastly here are the filtered time series of April – June of 2008 and 2009.

Filtered time series for April – June 2008

Filtered time Series for April – June 2009 with the same scale as 2008 (above figure)

Filtered time series for April – June 2009 with a different scale to see the variability over time more clearly.

Hopefully we can see more interesting and exciting results from the instruments that the Nares Strait team picked up this summer even though they were hit hard by the 2010 Petermann Ice Island!

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

→ 1 Comment

Posted in Ice Arch, Ice Cover, Oceanography

Tagged , , , , , ,