Category Archives: Nares Strait 2012

Rules of Engagement: Ships, Science, and Democracy

The FS Polarstern will leave port tomorrow night for scientific work between Greenland and Spitsbergen near 79 degrees north latitude about 1200 km or 770 miles from the North Pole. It will be hard work, as there is more ice in Fram Strait than any other area that I sailed into the past 20 years. The early June departure date is the cause not a changing climate. I am usually home during the birthday of my wife this week and our wedding anniversary next week as usually my work does not get me into the Arctic until the end of July, but this year is different.

As on all ships everywhere, the rules of engagements, the daily cycle of life, the access to friends, family, and the news cycle change once at sea. Some things one leaves gladly behind such as dirty laundry, washing dishes, and cutting the lawn, while others are a little harder to let go such as a blooming garden, growing children, riding bicycles, and open internet connectivity. The latter does not fit romantic notions of life at sea, but a button on my jumper says “Geek” for a reason. Furthermore, I found the button in an ammunition box in the woods near my hometown while geocaching with my wife of 20 year; Mary Ann, I miss you.

The ship is afloat, loaded, and a new set of rules now applies about how one lives aboard. This is my last post that will not be approved by the Captain, the Chief Scientist, and/or one of their designated representatives. This is a perfectly acceptable, reasonable, and normal way to do business, because the ship represents more that just one perspective of one writer with one national or one educational background. Every ship has a mission and there are formal ways to report on those. Blogging is not one of them, but public outreach, education, and perhaps serving a greater public good is. Once at sea, the Captain’s rules of engagement are absolute on any ship anywhere for good reason.

Hence ships are not democratic institutions, but authority, command, and accountability are all vested in one person, the Captain. Ships such as the FS Polarstern do represent democratic societies, cultures, and values rather well on a time scale longer than a news or blog cycle. Furthermore, fun stuff happens anyway and may not need reporting in gory detail: over breakfast today, we had six scientists sitting together from six countries with divergent perspectives on issues ranging from ice algae and ocean currents to gun and tax laws. Most of us had never heart of each other, because we all represent diverse disciplines such as biology, chemistry, meteorology, or physics. Diversity is both fun and strength; nothing is more boring than everyone looking or thinking the same about religion, politics, or science.

There exists, I believe, an analogy between the non-democratic character of ships and the non-democratic character of science. On ships as in science the majority does not rule or decide what is right and what is wrong; a committee may vote and advise on how monies are allocated, but no committee decides on what is and what is not accepted truth. The data we collect, the though experiments we codify, the observations we simulate, and the predictions we make, all these are facts that test our ideas, that scrutinized our theories, and that show what is most likely to happen from a multitude of scientists of diverse training and background. Yet an essential part of this process is that the data must be shared, the results must be published, the publication must withstand scrutiny all according to democratic rules such as fair play, checks and balances, and transparency, however, the process itself is not democratic.

So, where does this leave me now? I move my mind towards being at sea where a different set of rules applies. Uncertainty exists on what can and what cannot be written and published on what schedule. There need not be a design to limit or censure communication, but Ocam’s Razor applies: People aboard work tirelessly at almost all hours of the day, those with command authority are burdened with multiple, often contradictory demands, or internet access off Greenland is so severely limited that only ice-charts and data for navigation reach the ship.

I love to write, share, edit, and think. And if the blogging does not work the next few weeks, some other form to share excitement and results will eventually find its way, as it always does. The path is the goal.

P.S.: Happy Birthday and Anniversary, Mary Ann und einen wunderschoenen Achtzigsten, Vati. Ich denke an Euch all, I am thinking of you all ;-)

Measuring Ice Thickness From The Ocean

Ice floats and moves abouts. It melts in summer, it freezes in winter, but it moves from here to there driven by winds and currents. Some ice leaves the Arctic Ocean via Fram Strait to the east of Greenland and some leaves via Nares Strait to the west of Greenland. For the last 11 years I worked with Canadian friends in Nares Strait, but this summer I will work on the other side of Greenland with German, Polish, and perhaps Norwegian colleagues in Fram Strait. This opportunity already helps me solve puzzles in Nares Strait and more generally how ocean currents around Greenland impact ice cover, thickness, and flux.

Jonathan Poole in 2012 with ice profiling sonar hit by ice.

Jonathan Poole in 2012 with ice profiling sonar that was hit by ice.

One of our many instruments measures the thickness of ice. Our sensor package is moored on the ocean floor and quietly sends out a single ping every few seconds. Think of this ping as the sound you make when you tap your desk with a finger. The sound travels from the desk to your ear where you hear it, because your inner ear has a drum that picks up the vibrations that the taping makes when it hits your ear-drum. Well, our ice-profiling sonar sends out this ping that travels through the water to the ice above, bounces off the ice, and returns to our sensor. We then measure the time it takes for our ping to travel to the ice and back. If we know the speed of sound in the water, if we know the density of the water, if we know the pointing direction of the sonar, and if we know how much water is above our sensor, then we can estimate the thickness of the ice. The sketch below shows design details that go into keeping such a sensor system in the ocean recording data for 2-3 years at a time.

Sketch of ice-profiling sonar mooring deployed on the bottom of the ocean. Design by Dr. Humfrey Melling of Fisheries and Oceans, Canada.

Sketch of ice-profiling sonar mooring deployed on the bottom of the ocean. Design by Dr. Humfrey Melling of Fisheries and Oceans, Canada.

There are lots of challenges to deploy such a sensor system, there are more challenges to find and recover it in later years, and then there are the challenges to analyze and interpret the data writing the software that does it all. None of the many parameters such as speed of sound, ocean density, atmospheric pressure, and amount of water above the sensor are known very well, all of them change with time from day-to-day and sometimes even hour to hour. In order to measure ice thickness within a few inches (10 centimeters, say), we need good estimates of these things. I work with PhD student Patricia Ryan on this and we are almost done to untangle these many data strands for all of 3,300 days that we have observations in Nares Strait. Lets start with a random day exactly 10 years ago:

Ice draft below sea surface for May 30, 2004 in Nares Strait. Data shown are 15 second averages.

Ice draft below sea surface for May 30, 2004 in Nares Strait. Data shown are 15 second averages.

The bottom of the ice is about 1 meter (~ 3 feet) below the surface, but at about 6 pm (18:00) it becomes 0.2 meter thinner to return to its original thickness near midnight. A thicker piece of ice must have moved in and out of the “view” of our sensor. So far, so good, but you can already see that ideally I also would want to know the motion of the ice in addition to its thickness, but that is another story. Also, please recall that we got about 9 years of such data or about 3,300 plots, so, let me show you a second one, but this one is really bad:

Ice draft below sea surface for April 18, 2005 in Nares Strait.

Ice draft below sea surface for April 18, 2005 in Nares Strait.

The ice here is a little thicker, but not by much. What stands out are three funky looking, abrupt jumps every 6 hours precisely. How can this be? Well, it cannot and I must have done something bad to the data. Recall that we need speed of sound and water density estimates to convert acoustic travel time to ice draft. On April 18, 2005 my estimates perhaps were off. But why? And how can this be fixed?

The first clue is revealed in a month-long series of speed of sound that I estimated from a different mooring that measures temperature, salinity, and pressure along a string. Using some fancy math that a prior PhD student of mine developed (Dr. Berit Rabe), I estimate the vertical sound speed averaged from 100-m depth where the ice-profiling sensor is located to the surface where the ice is located. The plot below shows how this speed varies during the month of April 2005. It has some wild undulations near April-18:

Vertically averaged sound speed for the month of April 2005. Black curve is for 6-hourly and blue curve is for 24-hourly estimates.

Vertically averaged sound speed for the month of April 2005. Black curve is for 6-hourly and blue curve is for 24-hourly estimates.

For most of the month the speed of sound is about 1440 meters per second (m/s), but it spikes to almost 1446 m/s on April-18. It is this unrealistic spike that causes the estimated draft of the ice to go up and down by 20 to 30 centimeters.

The second clue and likely fix to my “ice offset problem” is the blue curve in the above plot. Using the same fancy math, I there come up with an estimate of the speed of sound only once a day rather than once every six hours. There are still fluctuations, but they are much smaller without a big spike. So, to conclude, I pushed my fancy math too far and it crashed the same way that a flashy muscle car driven too fast will crash as either the car or the driver cannot handle the road anymore. I here crashed the car as physicists are prone to do. Ideally we do it in a safe environment such as crunching numbers on a computer … as I did here.

Hansen, E., Gerland, S., Granskog, M., Pavlova, O., Renner, A., Haapala, J., Løyning, T., & Tschudi, M. (2013). Thinning of Arctic sea ice observed in Fram Strait: 1990-2011 Journal of Geophysical Research: Oceans, 118 (10), 5202-5221 DOI: 10.1002/jgrc.20393

Rabe, B., Johnson, H., Münchow, A., & Melling, H. (2012). Geostrophic ocean currents and freshwater fluxes across the Canadian polar shelf via Nares Strait Journal of Marine Research, 70 (4), 603-640 DOI: 10.1357/002224012805262725

Arctic Heart Beat and Disappearing Old Ice

Have a look at this beautiful movie that shows how the Arctic Ocean moves its oldest and thickest ice around from 1987 through 2013:


[Credits: Dr. Mark Tschudi, University of Colorado and NOAA's climate.gov.]

The Beaufort Gyre moves ice off western Canada and Alaska clockwise while the Fram Strait outflow between eastern Greenland and Spitsbergen exports much of the ice into the North Atlantic Ocean with the East Greenland Slope Current. The dividing line between the westward flux (into the Beaufort Gyre) and the eastward flux (into Fram Strait) stretch out to the north of the Canadian Archipelago and Greenland.

My only quibble is that, according to the movie, no old ice exits via Nares Strait or the Canadian Archipelago which is not true. During our field work in Nares Strait from 2003 through 2012 we always met rather heavy, thick, and old ice streaming south:

A graduate student in our oceanography program, Autumn Kidwell, is credited with directing me to this movie. Oh, and the Norwegian Ice Service in Tromso has a job opening for a smart remote sensing person ;-)

Petermann Photos, Places, and People

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

Did I ever see a Polar Bear?

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.