Fjords of the High Arctic

A few weeks ago, I was reading a book about glaciology recently when a sentence caught my eye.  Many advances in our understanding of how glaciers developed and transformed our world during the last ice age came from studying the Canadian landscape.  In particular:

A benchmark example [of paleo ice sheet reconstruction] was the compilation of the first Glacial Map of Canada in 1959, followed by its update in 1968, by the Geological Survey of Canada, based on painstaking aerial photograph and field mapping by its officers on a map sheet by map sheet basis after the completion of the aerial photograph coverage for the whole country in the 1950s.

This caught my eye, because I knew that my Grandpa on my Dad’s side of the family was a pilot who flew a lot of aerial surveys for the Canadian government in the late 50s.  I mentioned this to my Dad, just thinking he’d say, “gee, that’s cool”, and move on.  Apparently that triggered something in him though, because a few days later my email inbox was filled with a treasure trove of old family photos that I had never seen before.  In recent years I have also developed an interest in Arctic coastal geomorphology, so this discovery scratched a couple of itches for me.

One of the photos was taken above Alexandra Fjord on Ellesmere Island, which is insanely far north (78°N!):

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Alexandra Fjord, Ellesmere Island.  Photo copyright B.G. Pearson.

The cool thing is that when I went into Google Earth, I was able to snoop around and actually to find the same vantage point.  To my surprise, it seems like the glaciers there haven’t changed much since my grandfather was there in 1957:

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Alexandra Fjord today, seen in Google Earth.

However, Dad pointed out that perhaps the glacier at the front hasn’t changed, but that the ice field behind it has shrunk.  He probably has a point there…

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So pristine!  Photo copyright B.G. Pearson.
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My Grandpa’s airplane on the right hand side.  Photo copyright B.G. Pearson.

Why was he actually up there, and what were they surveying?  A series of radar transponders were set up across northern Canada so that the airplanes could precisely triangulate their positions .  Based out of Ottawa, my Grandpa and his colleagues carried out many long flights between remote destinations A newspaper article from 1957 describes the tremendous undertaking that mapping the entire Canadian Arctic was, apparently the world’s most ambitious aerial survey operation at the time:

SEVEN-YEAR JOB: Rockcliffe Squadron to Complete Mapping
Monday, March 25, 1957

“Planes from the RCAF’s 408 Photo Squadron at Rockcliffe Airport will fly to within 450 miles of the North Pole this Spring to complete the geodetic survey of Canada which it started seven years ago.”

“Using the huge USAF base at Thule, Greenland, and RCAF’s own base at Resolute Bay, both well within the Arctic Circle, the planes will criss-cross approximately 400,000 square miles of Arctic wasteland to produce reference points for the accurate mapping of Canada.”

“This year’s aerial mapping mileage will bring over 3,000,000 square miles – approximately 90 percent – of Canadian territory accurately surveyed by the Air Force. When the 300 men of the squadron return to base here about July 1, they will have completed the world’s greatest aerial survey operation.”

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Survey points in the Canadian Arctic from the 1950s.  My Grandpa flew some of the northernmost missions.

While the mapping operation may have been motivated by a Cold War-era push to map Canada’s north for defense purposes, the operation was also of great scientific benefit.  In addition to providing a wealth of useful data for glaciologists, the measurements also provided important insights into other fundamental geophysical questions.  For instance, the earth is not a sphere, but rather an oblate spheroid, or something like a squashed rugby ball.  But even then, gravity is weird and complicated, so the rugby ball comparison only takes you so far, and precise measurements are necessary to figure out all of the actual irregularities in Earth’s shape.

Measurements like these have many applications, including for estimating sea level rise rates.  By understanding how the Canadian Arctic is rebounding in response to deglaciation, scientists can better answer Tricky Questions About Sea Level Rise there.

One of my favourite stories from the 1957 article involved some of the corrections that were made to previous maps:

“Throughout the … programme, many positions believed to be accurate were found to be in error. In 1956, for example, Prince of Wales Island (in which the North Magnetic Pole was then located) was found to be three miles further south than was indicated on the map.”

“Although they didn’t possess any supernatural strength to move mountains, from such discoveries as this, the members of the 408 Photographic Squadron did, facetiously, claim the ability to move islands.”

I would thus like to think that all my research on islands is simply carrying on a Pearson family tradition!  My Dad (a civil engineer) also worked in the Arctic during the 1980s, constructing artificial islands in the Beaufort Sea.  That’s a story for another time, though!

Speaking of Pearson family traditions, I can see that my Grandpa also had a clear eye for photographic composition, a gift that my Dad quite strongly inherited:

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Airship on some remote runway in the far Canadian north.  Photo copyright B.G. Pearson.

Another reasons I was so delighted by these photos is because one of my favourite painters, Lawren Harris, also spent a lot of time in the Canadian Arctic. I have always felt drawn to his dramatic mountain landscapes capped with snow, and nary a tree for thousands of miles.  The mountains of the far north have a particular shape to them, which seems unique compare to most of the mountains I have seen with my own eyes.

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Mount Thule, Bylot Island, by Lawren Harris, one of my favourite painters.  He had a very unique view of the same Arctic landscapes my Grandpa used to fly over.

I made it as far north as Lofoten in Norway (68°N), and have flown over parts of the Arctic on transatlantic summer flights, but have never actually set foot on those rugged and remote hills.  Something for my bucket list!

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One more of Alexandra Fjord from space, because I can’t get enough of the staggering beauty of these landscapes.  [Source: Sentinel 2 L1C on July 17, 2019]

Sand: Dunkirk Beach

Here is another sample brought back by my friend Claudia, from Dunkirk Beach in northern France.  Dunkirk is famous from the Second World War, when the Nazis had cornered Allied troops there and forced a major evacuation across the English Channel.

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This is where my inner history nerd and my inner sand nerd collided to ask an interesting question: is the sand on that beach now (and in the photograph below) the same sand that was on the beach during the famous evacuation?  There’s no easy answer to that question, but as it so closely relates to the main research questions of my PhD, I can’t resist indulging in such a thought experiment.  Shall we try together?

To answer this question, let’s ask ourselves a few things:

  1. What kind of sand is on the beach?
    The size of the sand grains will determine how easily it is moved around by the waves and tides.  Bigger particles require more energy to move, and are thus more likely to stay where they are.  In general, smaller sand grains are more likely to get picked up and transported far away*.  Based on the photo above, let’s assume that most of the sand grains are about 200 μm in diameter (that’s 0.0002 m).
    The sand also seems to be mainly made of clear or white-brownish grains, so we can probably make a safe guess that they are mainly made of quartz.  This will come in handy later if we need to make an assumption about how dense the particles are. Most of this sand comes from large sand banks offshore, which is moved to shore by waves during large storms [1].
  2. How do waves and tides shape the coastline here?
    To predict how sand moves around on a beach, we need to understand the behaviour of the water there.  The tidal range on this part of the French coast is quite large, between 5-8 m [1]. That large range means that a correspondingly massive volume of water is moved back and forth past the beach twice a day, which generates powerful tidal currents.  Waves here mainly come from the English Channel to the west or the North Sea to the northeast, and are generally at their strongest during occasional winter storms.
  3. In which direction does the sand usually move?
    There are several possible fates for our 1940 sand: (a) staying where it is, (b) moving offshore into the English channel, (c) moving westward towards Calais, (d) moving eastward to Belgium, or (e) moving onshore to build up the sand dunes there.
    At these beaches, the tidal currents moving eastward towards Belgium are slightly stronger than the ones moving westward back towards England [1].  This is eastward motion is reinforced by waves and wind-driven currents, which also tend to move eastward on average [2].  As a result, the sediment effectively takes two steps forward and one step back, gradually moving in an eastward direction (i.e. (d) rather than (c)).
    We also know that there is a regular supply of sand from offshore [2], so let’s rule out (b) for simplicity. The dunes in that area are also relatively stable [2], so let’s rule (e) out, too.  If most of the sand is then either moving east (d) or staying put (a), what is the likelihood that our 1940 sand is still there?
  4. Have humans intervened with the coast there?
    In 2014, the French government created the largest sand nourishment in the history of France on the beach at Dunkirk [3].  This is visible in Google Earth as the giant pile of sand near the red pin (below).  If there was still 1940 sand on the beach there, it is now likely buried underneath the nourishment.  Depending on where my friend collected her sand, there is a good chance that it is made up of this sand that was dredged from the nearby harbour, rather than sand that was on the beach in 1940.

    I had a similar issue with my tracer study: several months after our investigation, the Dutch government placed a huge nourishment right on top of our study site.  That means that even if some of our tracer sand is still out there, it is likely buried deep beneath a giant pile of sand, which means that we can’t go back there to take more samples.
  5. What is the likelihood of sand leaving the beach?
    After placing the nourishment at Dunkirk in 2014, scientists monitored how the beach changed, and found that it lost 9% of its volume in 2 years [3].  Most of this sand appeared to migrate eastward, as predicted by those other studies.  If we had similar data about how much the volume of the beach has changed in the past 80 years, we could estimate the rate at which sand is leaving, and hence how likely it is to still be there.  From that, we could come up with a sort of “residence time”: how long we expect sand to remain on the beach given the volumes that are coming in from offshore sandbars and leaving down the coast.  That would at least give us a ballpark idea of what to expect.  We could also use computer simulations to more precisely predict this transport, but that’s a lot of work for our little thought experiment!

Given all of this information, I would guess that most of the sand that was on the beach in 1940 is somewhere on its way to Belgium, or is still there but buried beneath the new nourishment.  Based on the assumptions that we made about this being quartz sand about 200 μm in diameter, we can estimate that in a handful of sand (say, 250-300 mL), there will be about 5 million individual grains!** If we scale this up to an entire beach, then I think the odds are good that at least a few grains have stuck around since then.

There are lots of different ways that you could go about this, though- how would you try to tackle it? Am I missing anything important?


* This “smaller-particles are more likely to get picked up by the waves and currents” rule only works for sand grains that are all more-or-less the same size. If your sand has both large and small particles, you can also have “hiding” effects where little grains of sand hide behind big grains and are harder to move. And don’t even get me started on mud! Mud particles (usually 10-100 times smaller than sand) obey a whole other set of complicated rules that are frankly a little absurd sometimes. But these are discussions for another time…

** Even though the grains in that picture are clearly a bit irregular in shape, we can pretend that they are spheres and calculate their volume Vgrain = 4/3π(0.0002/2)3 = 3.3×10-11 m3.  The volume of your hand Vhand is 300 mL = 3×10-4 m3, so we can calculate the number of grains as Vhand /Vgrain, which is about 9 million. But wait! We have to account for all the spaces in between the sand grains, since we’re not dealing with a solid block of quartz. This is usually about 40% for sand, so this is how we get our final number of about 5 million.


[1] Sabatier, F., Anthony, E. J., Héquette, A., Suanez, S., Musereau, J., Ruz, M. H., & Régnauld, H. (2009). Morphodynamics of beach/dune systems: examples from the coast of France. Géomorphologie: relief, processus, environnement15(1), 3-22.

[2] Anthony, E. J., Vanhee, S., & Ruz, M. H. (2006). Short-term beach–dune sand budgets on the north sea coast of France: Sand supply from shoreface to dunes, and the role of wind and fetch. Geomorphology81(3-4), 316-329.

[3] Spodar, A., Héquette, A., Ruz, M. H., Cartier, A., Grégoire, P., Sipka, V., & Forain, N. (2018). Evolution of a beach nourishment project using dredged sand from navigation channel, Dunkirk, northern France. Journal of Coastal Conservation22(3), 457-474.