Tag Archives: Newfoundland

Shots of Airborne Lasers at Petermann Gletscher, Greenland

If shots of whiskey make you dizzy, shots of laser stun. NASA stunned me this week, when I discovered that they provide millions such shots of Greenland from which to construct detailed images of the landscape. The shots are free, no age-limit. This is better than the usual remote sensing or photography of “just” brightness. The laser gives us height, and not just the perception of it by shadows and fake angles of illumination, but hard and direct measurements of, well, height above sea level. Have a look at several million such shots of Petermann Gletscher taken in 2010 before the glacier broke to Manhattan-sized pieces:

Petermann Glacier surface elevation from laser shots on Mar.-24, 2010 at the site where the Manhattan-sized ice island formed Aug.-6, 2010. The background shows the same scene at the same time at 250-m resolution from MODIS (see below). Colors along the 350-m wide laser track line show height above sea level in meters.

Petermann Glacier on March 24, 2010 as seen from MODIS satellite at 250-m resolution with two flight tracks along which laser data are collected. The black box shows the site of the figure above. The color figure on the right shows the slope or gradients of the data shown on left. It emphasizes regions where brightness changes fast. Multivariate calculus is useful!

We see two tracks: the one on right (east) has the ice stick more than 20-m above sea level (yellow colors) while about a mile to left (west) the ice’s surface elevation is only 10-m above sea level (light blue). Since the ice is floating and densities of ice and water are known, we can invert this height into an ice thickness. Independent radar measurements from the same track prove that this “hydrostatic” force balance holds, the glacier is indeed floating, so, multiply surface elevation by 10 and you got a good estimate of ice thickness. The dark blue colors of thin ice show meandering rivers and streams, ponds and undulations, as well as a rift or hairline fracture from east to west. This rift is visible both in the right and left track, it is the line along which the glacier will break to form the 2010 ice island. All ice towards the top of this rift has long left the glacier and some of it has hit Newfoundland as seen from the International Space Station by astronaut Ron Garan:

Last remnant of Petermann Ice Island 2010-A as seen from the International Space Station on Aug.-29, 2011 when it was about 3.5 km wide and 3 km long [Photo credit: Ron Garan, NASA]

Both are images of Petermann ice. The photo measures the brightness that hits the lens, but the laser measures both brightness and ice thickness. The laser acts like flash photography: When it is dark, we use a flash to provide the light to make the object “bright.” Now imagine that your camera also measures the time between the flash leaving your camera and brightness from a reflecting object to return it. What you think happens at an instant actually takes time as light travels fast, but not infinitely fast. So you need a very exact clock to measure the distance from your camera to the object. Replace the flash of the camera with a laser, replace the lens of your camera with a light detector and a timer, place the device on a plane, and you got yourself an airborne topographic altimeter. So, what use is there for this besides making pretty and geeky pictures?

The laser documents some of the change in “climate change.” Greenland’s glaciers and ice-sheets are retreating and shrinking. Measuring the surface and bottom of the ice over Greenland with lasers and radars gives ice thickness. The survey lines above were flown in 2002, 2003, 2007, 2010, and 2011. These data are a direct and accurate measure on how much ice is lost or gained at Petermann Gletscher and what is causing it. My bet is on the oceans which in Nares Strait and Petermann Fjord have increased the last 10 years to melt the floating glacier from below.

There is more, but Mia Zapata of the Gits sings hard of “Another Shot of Whiskey.” What a voice …

ResearchBlogging.org

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

Krabill, W., Abdalati, W., Frederick, E., Manizade, S., Martin, C., Sonntag, J., Swift, R., Thomas, R., & Yungel, J. (2002). Aircraft laser altimetry measurement of elevation changes of the greenland ice sheet: technique and accuracy assessment Journal of Geodynamics, 34 (3-4), 357-376 DOI: 10.1016/S0264-3707(02)00040-6

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

Thomas, R., Frederick, E., Krabill, W., Manizade, S., & Martin, C. (2009). Recent changes on Greenland outlet glaciers Journal of Glaciology, 55 (189), 147-162 DOI: 10.3189/002214309788608958

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

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.

Nares Strait 2012: Grounded in St. John’s, Cod, and Crossing of Lines

Hurry-up and wait: The rushed 5 am arrival at St. John’s airport this morning turned into a six-hour wait and a canceled departure for Thule, Greenland. Crew, officers, and scientists are all grounded and spend an extra night waiting. There is lots of talk about screeching-in and uncertainty if membership in the “Order of the Blue Noses” or the “Order of the Gold Dragons” substitutes the more mundane “screeching-in.” Let me explain:

Canadian authorities aboard CCGS Henry Larsen.

The CCGS Henry Larsen originates from St. John’s and most of its officers and crew are local to the town, island, and icy waters offshore where cod once ruled supreme until mis-managed industrial-scale offshore trawling almost wiped the cod out and destroyed much of the local economy that was based on cod for centuries.

Time series of (a) catch of cod (in 106 tonnes) over the Newfoundland and Labrador shelf (b) the total abundance of Gadidae over the southern Newfoundland shelf (c) the catch of shrimp and (d) crab over the Newfoundland and Labrador shelf (e) the greenness index from the Continuous Plankton Recorder (CPR) over the southern Newfoundland Shelf (f) bottom temperature from inshore on the southern Newfoundland shelf and (g) the North Atlantic Oscillation (NAO) index. The heavy solid lines in panels (f) and (g) represent low-pass filtered smoothed curves of the plotted data. [From DeYoung et al, 2004: Detecting regime shifts in the ocean, Prog. Oceanogr., 60, 143-164.]

The CCGS Henry Larsen has two crew who rotate on and off the ship every 4-8 weeks. Over the years I have met many crew who hailed from families who had worked the cod on smaller, inshore boats. They are superb and experienced sailors who know how to handle and run ships and all attached to it in harsh and icy waters. But how does this relate to screech and cod? Let me digress a moment by comparing US and Canadian Coast Guards:

The U.S. Coast Guard’s ice breaker operates 24-hours/day under military rules without alcohol or overtime to be had. In contrast, the civilian Canadian Coast Guard operates less hours at full strength with some alcohol and some overtime served in moderation. The cultures aboard US and Canadian vessels differ: US ships are permanently in training with young crew on 6-month deployments moving to a new assignment each year, while Canadian ships are working with an older, more experienced, and steady crews. The Canadian crews do the same amount of work in 12-18 instead 24 hours with 1/3 the staff. Ironically, US ships have more “unclassified” electronic capabilities with many more advanced sensor systems. Both ships also have “classified” sensors and missions that I know nothing about, but I digress. Cod and screech are potentially aboard Canadian ships operating out of Newfoundland only.

CCGS Henry Larsen crew at work: Deployment of a tide gauge (subsurface pressure sensor) in Alexandra Fjord. This is one of the instruments we will recover from Nares Strait that was deployed in 2009.

Our small motley crew of eight scientists this year consists of 4 Canadians from British Columbia, 3 Americans from Delaware, and 1 Dutch from England. Yesterday night we all converged at a fine restaurant on Ducksworth Street in downtown St. John’s, Newfoundland. A dispute is still raging among us on what is valid proof of earlier”screeching-in?” I learnt the hard way, that “laminated certificates” are invalid, but what about “un-laminated certificates?” The former are easily obtained in the vibrant port city of St. John’s with its many bars and pubs. The “un-laminated certificates” may be valid, if signed and authenticated by an officer of the CCGS Henry Larsen aboard said ship, but enforcement has been selective.

There are also arguments, that a crossing of the Arctic Circle (certified by a Commanding Officer of a Canadian Coast Guard ship) or the crossing of the International Dateline north of the Arctic Circle (certified by a Commanding Officer the CCGS Henry Larsen) may supersede the more common “screeching-in” ceremonies and certificates. I am the main person making these arguments facing authorities with powers that exceed mine by far.

Our failure to leave for Thule, Greenland today may give some of us a chance to get potentially needed “screeching-in” certificates, but I very much doubt that these “laminated certificates” carry much weight. Time will tell. It will also tell if we get to Thule tomorrow. Hurry-up and wait.

Nares Strait 2012: First Challenges and Petermann Ice Island Coming

Petermann Glacier’s 2012 ice island is heading south, the Canadian Coast Guard Ship Henry Larsen is heading north, and my passport went through the washer. Ticket agents at Philadelphia airport refused to accept my worn passport to get into Canada. My journey appeared at a dead-end, but ticket agents, U.S. State Department employees in downtown Philadelphia, and a Jordanian cab driver got me to Canada with a new passport, a new ticket, and a new lesson learnt in 4 hours. I did not believe it possible, but it was. I arrived in Canada with an entire day to spare.

Over the years I learnt to plan and budget generously for Arctic research, and then improvise with what is available. I was taught to bring spares of all critical equipment to prepare for loss and failure. I learnt to allow for extra time as missed planes, weather, and who knows what always make tight schedules tighter, like passports going through washers. I learnt that patience, civility, co-operations, and seeing the world through other people’s eyes and responsibilities get me farther than fighting. After I got my PhD in 1992, I learnt that the very people who cause troubles by enforcing rules and regulations are often also the most likely to know the way out of trouble. The ticket agent who denied my passport was also critical to help me get a new one. Thank you, Beth.

Our science party of eight from Delaware and British Columbia and the ship’s crew of 30-40 from Newfoundland will meet on the tarmac of St. John’s tomorrow at 4:30am, fly to and refuel at Iqaluit, Nunavut, and arrive at the U.S. Air Force Base at Thule, Greenland. The crew who got the ship from St. John’s to Thule will return with the plane home. It usually takes two days sailing north by north-west to reach Nares Strait from Thule, but this year the ice will be a challenge far greater than getting a new passport in 4 hours.

Western North-Atlantic and Arctic regions with Greenland in the west (top right) and Canada (left). Blue colors show bottom depth (light blue are shelf areas less than 200-m deep) and grey and white colors show elevations. Nares Strait is the 30-40 km wide channel to the north of Smith Sound, Baffin Bay is the body of water to the south of Thule.


The ice island PII-2012 is moving rapidly towards the outer fjord at a rate that increased from 1 km/day last week to 2 km/day over the weekend. I expect it to be out of the fjord an in Nares Strait by the weekend when we were hoping to recover the moorings with data on ocean currents, ice thickness, and ocean temperature and salinities that we deployed in 2009. The ice island is threatening us from the north: Without a break-up, it is big enough to block the channel as another large ice island did for almost 6 months in 1962.

Petermann Glacier, Fjord, and Ice Island on July 31, 2012 at 08:05 UTC. Nares Strait is to the top left. Petermann Glacier, Greenland is on bottom right. PII-2012 is at the center.


At the southern entrance to Nares Strait, lots of multi-year ice is piling up near the constriction of Smith Sound. Winds and currents from the north usually flush this ice into Baffin Bay to the south, however, the same winds and currents will move the ice island out of Petermann Fjord and into Nares Strait. We will need patience, humility, and luck to get where we need to be to recover our instruments and data. A challenge that cannot be forced, we will likely wait and go with the flow rather than fight nature. We will have to play it smart. We are the only search and rescue ship for others. I am nervous, because this year looks far more difficult than did 2003, 2006, 2007, or 2009. In 2005 we were defeated by the winds, but that is a story for a different day.

The currents and winds of Nares Strait

[Editor’s Note: Undergraduate Allison Einolf of Macalester College in Minnesota summarizes her work at the University of Delaware that was supervised by Andreas Muenchow as part of an NSF-funded summer internship.]

I’m about to fly to Thule, Greenland for a research expedition into the Nares Strait. We had planed to survey Petermann Fjord, but our proposed cruise track is facing an obstacle twice the size of Manhattan.

We’re heading up north to pick up instruments that have recorded current velocities, salinity, temperature, and ice thickness in Nares Strait since 2009. I’ve been working all summer on data retrieved on a similar cruise three years ago, focusing on what effects the ice arches have on currents north of the ice arches.

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

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.

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