Category Archives: Greenland

Ice, ocean, and glacier change in northern Greenland

Steffen Olsen is a Danish physical oceanographer with a skill to present beauty to an artist like my wife and a scientist like me. Three days ago he posted a photo on Twitter with these words

Local hunters from Qaanaaq navigating our CTD system in the frozen ice mélange in front of Tracy Galcier 66W 77N to measure the ocean below. Heat loss to melting of glacial ice leaves the ocean at sub-zero temperatures down to 400m @arctic_passion @dmidk @ruth_mottram

Photo: Dogsled from Qaanaaq near the northern edge of Tracy Gletscher in Inglefield Fjord April 2022. [Credit: Dr. Steffen Olsen, Danish Meteorological Institute.]

Steffen’s photo shows his study area, research platform, and mode of transportation. There is a glacier in the background between the rocks on the left (north) and unseen mountains to the right (south). Equally unseen is the ocean under all this crushed and broken and piled up sea ice covered by fresh snow. We see tracks of people walking to the vantage point from where the photo is taken. The dogs rest on a small patch of level sea ice perhaps 3-5 feet (1 to 1.5 meters) thick.

There are boxes on the sled that contain gear to drill through the sea ice and then to send a probe down towards the ocean bottom to measure ocean temperature, saltiness, and oxygen during its decent. I did similar work with a snowmobile in 2017 based at Thule Air Base for 6 weeks. Steffen and I work together on such data. He collected these every year since 2011 both adjacent to Tracy Gletscher and along most of the ~120 km long and ~1000 meter deep fjord. I am grateful to Steffen to share this photo: It helps me to focus on my passions rather than my outrage at soldiers and leaders of the Russian Federation in their war to destroy Ukraine and its people building a free, vibrant, and democratic country for themselves. There is more, but I stop here now.

Let me start with a map of where in Greenland the photo was taken and where Steffen collected his data each since 2011. The red star in the insert top-right shows the location of the map between Canada and Greenland. I color ocean bottom depths in blue shades and land heights in green, yellow, and brown shades. The glacier in Steffen’s photo is at the north-eastern end of Inglefield Fjord where I placed the label Tracy. The label Qaanaaq shows where about 650 Inughuit live along the coast near the center of the fjord. It probaby took the dogs about 2-3 days to travel with their cargo from Qaanaaq to Tracy Gletscher. Red dots are stations served by a Danish Navy ship in the summer of 2015, but I here only talk about the blue dots.

Figure: Map of the study area with ocean sampling stations in Inglefield Fjord (blue dots) and adjacent northern Baffin Bay. [Unpublished own work.]

The blue dots are stations where Steffen and his companions drilled through the sea ice in 2018. Note that some of those ocean stations appear on land. This cannot be, but the glacier has retreated between the time the topographic data was collected and 2018 when Steffen collected the ocean data. Three LandSat satellite images below show how the glacier changed from 1973 to July and August of 2021. Icebergs are visible, too. A citizen scientist with the handle “Espen” at the Arctic Sea Ice Forum extracted these satellite photos from public U.S. databases. He is part of an online international community of Greenland and sea ice enthusiasts who posts at this forum for over a decade making daily discovers. These are people with regular jobs that in their spare time post satellite imagery and open data they found which they share openly often with insightful interpretations. It is citizen science at its very best. I go there often to read, ask, and learn. I even met a prominent member once for lunch when visiting Copenhagen on my way to Greenland. He gifted me LandSat imagery of my favorite glaciers printed on cloth that I framed for its scientific and artistic beauty. Thank you, Espen 😉

Gallery: Space photography (LandSat) of glaciers terminating from the Greenland ice sheet in Inglefield Fjord in 1973 (right), July 2021 (center), and August 2021 showing the retreat of Tracy but not Heilprin Gletscher. [Credit: Espen Olsen at Arctic Sea Ice Forum.]

So how does the ocean below all this ice next to a glacier look? Well, lets look at a set of station from Qaanaaq to Tracy Gletscher that shows how temperature, salinity, and oxygen of the water changes both with depth and along the fjord. We always find very cold, somewhat fresher, and highly oxygenated water near the ocean surface about 40 m (near glacier) to 100 m (near Qaanaaq) below the sea ice and warmer, saltier, and less oxygenated water below with a temperature maximum of 1 degree Celsius near 300 m depth. It is this warm water that melts the adjacent glacier. As Dr. Olsen says “… Heat loss to melting of glacial ice leaves the ocean at sub-zero temperatures …” In other words, the deeper waters 1. enter the fjord at temperatures above zero degrees Centigrade, 2. reach the glacier, 3. cool down as they melt the glacier, and 4. leave the fjord at temperatures below zero degrees Centigrade. This is why the two stations near the glacier show slightly fresher and cooler waters between 300 and 500 m depth. This water contains the glacial melt. The section represents the 10 year average from 2011 through 2020.

Figure: Section of salinity (bottom), temperature (center), and dissolved oxygen (top) along Inglefield Fjord as an average of data collected annually between 2011 and 2020. [Unpublished own work.]

Earlier this year I tried to visit Copenhagen to finish this work that places this emerging story into both a historical and spatial context, but Covid restrictions derailed this and other plans. Nevertheless, have excellent data from 1928 when this fjord was first surveyed by Danish oceanographers. At that time the waters had dramatically different temperatures (much colder) and salinities (a little fresher) both inside the fjord and in Baffin Bay adjacent to it. The changes are probably related to a much changed sea ice cover and perhaps ocean circulation that relates how the winds impact the ocean with and without sea ice. For the 1979 to present satellite record, we can quantify how much sea ice covers both the fjord and adjacent ocean. I made the graph below last week from 14073 almost daily satellite images whose data the U.S. National Snow and Ice Data Center distributes freely. I show annual averages for each of the 42 years that these SSM/I satellites have been measuring sea areal coverage from space.

Figure: Annual averages of sea ice cover 1979 through 2021 with linear trend lines for two 21-year subsets (blue) and the entire 42-year record (red). [Unpublished own work.]

Before the year 2000 the sea ice cover fluctuated between 26,000 and 39,000 km2 and if one for how these changes are trending between 1979 and 2002, one finds a slight increase in the blue line, however, this increase is not significantly different from zero at a high 95% level of confidence. For the second period after 2002, the ice covered area fluctuates much less, from about 22,000 to 28,000 km2 and the trend line in blue now indicates decreasing sea ice cover. As before, however, this blue trend line is no different from zero at the same high level of confidence. We also notice that there is a red trend line that I derive from using all 42 years of data. This line is very different and statistically significant, but it does not quiet do justice to the almost step-like change that appears to happen around 2000 through 2005. What happened then? I do not know, yet, but this is the fun of doing science: There is always more to discover. The sea ice cover in northern Greenland does not always follow a straight line. This is not different from our climate or life. Expect the unexpected, adjust, and keep moving. Or in Dr. Olsen’s words:

“… you have a number of years where conditions don’t follow the more linear track of (predicted) scenarios,” explained Dr. Olsen. “A warming tendency can be reversed for some years, for example.” [From https://phys.org, Oct.-13, 2021]

Rotations, Spin, and People

I hate to rotate. It makes me sick. And yet, every day I spin at 800 miles per hour, because living on a spinning earth does this to me. Why does the earth spin at all? [CalTech answer.] Did it always spin the way it does now? [No.] Could it spin in the other direction that would make the sun rise above the horizon in the West rather than the East? [No.] If not, why not? [Not sure yet.] I am pondering these questions as I will teach my first undergraduate class in ten days:

I plan to introduce how oceans and atmospheres circulate to distribute heat, water, and “stuff” like food and plastics across the globe. There is lots of rotation, lots of angular momentum, lots of torque and I am unsure, if a text book and lecture via Zoom will make much sense. So, today I discovered several fun and smart and insightful videos that I may even pose to my students as Homework or Exam questions 😉

The first set of videos I discovered today is Derek Muller’s Veritasium channel on YouTube. He covers a range of physics, math, and even biology topics, but I here focus on his wing nut problem. He entertains by explaining a strange and even bizarre observation made in space some 30 years ago. A Russian engineering astronaut noticed a rotating wing nut change its rotational axis repeatedly. Russia kept the observation top secret for over 10 years for reasons not entirely clear, but here is a modern attempt to explain what happened. It also applies to how tennis rackets rotate:

Now this reminded me of a problem that I encountered during my third year studying physics in Germany. I never solved or understood this so-called spinning-hard-boiled-egg problem that the Physics Girl describes so well. Her real name is Dianne Cowern and I use her videos in my graduate statistics class where her voice and physics shatters wine glasses via resonance. Today I discovered many more of her PBS Digital videos that all are filled with fun, beauty, and smart explanations. She plays with vortices in air and water and in between.

Now how does this relate to oceanography and meteorology? Well, we all live somewhere on the spinning top or egg or peanut that we call earth. Gravity keeps us grounded, but rotating objects can do strange things as the above two videos show. And when rotation becomes important we are not just dealing with linear momentum, but also angular momentum. When rotation becomes important, we must consider torques that generate angular momentum in ways similar to how forces generate linear momentum.

Rotation adds a strong and often counter-intuitive element because unlike a force that accelerates a car in the same direction that the force is applied, a force applied to a rotating system generates a torque perpendicular to both the force and the direction to the rotational axis. This can be confusing and one has to either watch the movies or go through advanced vector calculus. Furthermore, a rotating sphere acts differently than a rotating spheroid which acts differently from a rotating triaxial spheriod. Our peanut earth is the latter and thus has at least three axes of orientation (a and b and c) that all have different kinetic energy and angular momentum states. This makes for wobbly rotations which are sensitive to changes in both force balances and the distribution of masses like ice and water that can move to different locations at different times and stay there for a while.

For a perfect sphere three perpendicular lines from the center to the surface all have the same distance a (top) while for a spheriod only two of the three perpendicular lines have the same distance from the center (bottom right). If all three perpendiculars are different then we have something called a triaxial spheroid [Adapted from WikiPedia].

And how does this relate to climate science and my beloved glaciers in Greenland? Well, there is the “global wobbling” that caused ice ages and warm periods as the earth’s principal axis or rotation changes or wobbles. The “global wobble” was discussed in hilarious way a few years ago by the United States House of Representative’s “Committee on Science, Space, and Technology.” Closing this essay, I let Jon Steward of the Comedy Channel speak and hope you find his commentary and live experiment as funny as I do:

How big is Greenland?

Maps of Greenland were sketched with broken bones, frozen limbs, and starved bodies of men and dogs alike. On April 10, 1912 four men and 53 sled dogs crossed North Greenland from a small Inuit settlement on the West Coast where today the US Air Force maintains Thule Air Base. In 1912 Knud Rassmussen, Peter Freuchen, Uvidloriaq, and Inukitsoq searched for two explorers lost somewhere on Greenland’s East Coast 1200 km (760 miles) away. They returned 5 months later with 8 dogs without finding Einar Mikkelsen or Iver Iversen. These two arrived in North-East Greenland to find diaries, maps, and photos of three earlier explorers who had starved to death in the fall of 1908. Mikkelsen and Iverson found the records, but struggled to survive the winters of 1910/11 and 1911/12 alone stranded before a passing ship found them. I ordered their 1913 Expedition Report yesterday.

Dog sled teams drive across Greenland’s Inland ice in April 1912 from Clemens Markham’s Glacier in the west to Denmark Fjord in the east. All 4 explorers returned, but only 8 dogs did.
Map of Greenland as included in the Report of the First Thule Expedition 1912 by Knud Rasmussen.

I worked along these coasts in 2014, 2015, 2016, 2017, and 2018 on German research vessels, Swedish icebreakers, Greenland Air helicopters, and American snowmobiles. We explored the oceans below ice and glaciers with digital sensors but without hunger, cold, or lack of comfort. I feel that I know these coasts well, read what others have written and suffered. I make my own maps, too, to reveal patterns of oceans, ice, and glaciers that change in space and time. And yet, I am often lost by distances and areas. I do not know how big Greenland is.

Clockwise from top left: Ocean observatory on sea ice off Thule Air Base (Apr.-2017); refuelling helicopter in transit to ocean observatory on Petermann Gletscher (Aug.-2016); Swedish icebreaker in Baffin Bay (Aug.-2015); and deployment of University of Delaware ocean moorings from Germany’s R/V Polarstern off North-East Greenland at 77 N latitude (Jun.-2014).

At home I know distances that I walk, bicycle, or drive as part of my daily routine. I know areas where I live from weather and google maps, weekend strolls, and where family and friends live. Once we travel in unfamiliar lands, however, we are lost. Americans rarely know how small most European countries are while Europeans rarely know how far the Americas stretch from Pacific to Atlantic Oceans. Nobody knows the size of Greenland or Africa. On World Atlases Greenland appears as large as Africa, but this is false. Just look at this map:

The size of Africa on the same scale as the USA (green), Greenland (orange), and Germany (blue). Germany is about the same size as Botswana while Greenland is a tad larger than Kongo and the USA is about as big as the Sahara.

Thus North Greenland’s explorers walked distances similar to walking across Texas, Mississippi, and Florida (and back) or distances similar to walking Germany from its North Sea to the Alps (and back) or distances similar to walking across Kenya (and back). Making these maps, I found the tool at https://thetruesize.com These playful maps compare Greenland’s size by placing its shape onto North-America, Europe, and Asia:

Three explorers starved and froze to death November 1907 because they underestimated their walking area. Their shoes wore thin and they walked barefoot. Daylight disappeared and was replaced by polar night. Food vanished with no game to hunt. Jorgen Bronland, Niels Hoeg Hagen, and Ludvig Mylius-Erichsen were 29, 30, and 35 years young when they died mapping Greenland. I sailed the ice-covered coastal ocean. I was helped by maps they made walking.

How oceans interact with Greenland’s last floating glaciers

Testifying before the US Congress back in 2010, I refused to endorse the view that a first large calving at Petermann Gletscher in North Greenland was caused by global warming. When a second Manhattan-sized iceberg broke off in 2012, I was not so sure anymore and looked closely at all available data. There was not much, but what little I found suggested that ocean temperatures were steadily increasing. Could it be that warm waters 1000 feet below the surface could melt the glacier at all times of the year? Did this melting from below thin the glacier? Did these changes increase the speed at which it moves ice from land into the ocean? These were the questions that motivated a number of projects that began in earnest in 2015 aboard the Swedish icebreaker I/B Oden. Professional videos of this expeditions are at https://icyseas.org/2019/07/04/petermann-glacier-videos-science/

Scientists and technicians from the British Antarctic Survey drilled three holes through the floating section of Petermann Gletscher to access the ocean and ocean sediments below it. The ocean temperature and salinity profile confirmed both the warming trend observed in the fjord and ocean adjacent to the glacier, but more importantly, we placed ocean sensors below the glacier ice to measure temperature and salinity every hour for as long as the sensors, cables, and satellite data transmission would work. This has never been done around Greenland, so our data would be the first to report in real time on ocean properties below 100 to 300 m thick glacier ice at all times. What we saw when the data started to come in after 2 weeks, a month, and half a year stunned us, because (a) the ocean waters under the glacier changed by a very large amount every two weeks. Nobody has ever seen such regular and large changes in tempertures (and salinity) under a glacier bathed in total darkness at air temperatures of -40 degrees Celsius and Fahrenheit, but then our station went offline after 6 months and did not report any data to us via satellite.

Helicopter flight path on 27/28 August 2016 to reach Petermann Gletscher (PG) via southern (Fuel-S) and northern (Fuel-N) fuel stops in northern Inglefield and southern Washington Land, respectively. Background color is ocean bottom depth in meters.

Refurbished Petermann Glacier Ocean Weather station on 28. August 2016 with Greenland Air helicopter and British Antarctic radar station in the background.

The first work on the grant was to visit our station by helicopter in 2016 using two fuel caches that we placed the year prior from the Swedish icebreaker. At this point Petermann Gletscher and our projects attracted the attention of journalists of the Washington Post who had read some of the blog articles at this site. The two journalists accompanied us for a week and produced a beautiful visual report of our work that is posted at

https://www.washingtonpost.com/sf/business/2016/12/30/with-enough-evidence-even-skepticism-will-thaw/

A detailed news report on our science and new findings appeared on page-1 of the Washington Post on January 1, 2017 [Broader Impacts]. I briefly summarize the results and findings of our subsequent data analyses of all data from August of 2015 through October of 2017 [Intellectual Merit]:

1a. Ocean temperatures increase at all five depths below the 100-m thick floating ice shelf of the glacier. These warmer waters are also saltier which demonstrates their Atlantic origin.

1b. Surface sensors indicate short, but intense pulses of meltwater passing our ocean array at spring-neap tidal cycles.

2a. Melt rate data reveal that these pulses occur during reduced tidal amplitudes and follow peaks in glacier melting that exceeded 30 feet per year.

2b. Statistical analyses indicate that the melt waters originate from a location near where the glacier sits on bed rock and that the melt water then moves seaward towards the ocean.

3a. Ocean melting below the glacier varies from summer (strong) to winter (weak) rising from a winter mean of 6 feet per year to a maximum of 240 feet per year during the summer.

3b. The large summer melting is caused by the increased discharge of subglacial runoff into the ocean near the grounding line.

3c. The larger discharge strengthens ocean currents under the floating glacier that drive ocean heat toward the glacier’s ice base.

The work formed one basis for the dissertation of PhD student Peter Washam who published the items #2 and #3 in the Journal of Physical Oceanography and Journal of Glaciology, respectively. He helped to drill holes and install sensors for the project that we first described at #1 in Oceanography. These three peer-reviewed journal articles are all published by not-for-profit professional organizations and societies dedicated to higher learning and public outreach. Furthermore we placed three separate data sets (1 | 2 | 3) at the Arctic Data Center that is funded by the National Science Foundation. More will come as we continue to work on the hard-won data from below Petermann Gletscher.

Look down the 0.3 meter wide drill hole. Yellow kevlar rope supports cable and ocean sensors.

Post Scriptum:
A modified version of the above was submitted the US National Science Foundation as part of the final reporting on grant 1604076 (“Glacier-Ocean interactions at a Greenland ice shelf at tidal to interannual time scales”) that funded this work with $360,400 at the University of Delaware from August 2016 through July 2019.

Scoresby Sund – Greenland’s Longest Fjord

Fog, fog, and more fog is all we saw as we approached Scoresby Sund aboard the German research ship Maria S. Merian from Denmark Strait to the south-east. The fog lifted as soon as we passed Kap Brewster and began work on ocean currents and waters at the entrance of this massive fjord system. My artist friend and wife Dragonfly Leathrum posted a wonderful travel essay with many photos that did not include these:

We were here to explore how the coastal ocean off Greenland may relate to Daugaard-Jensen Gletscher at the head of the fjord some 360 km away (195 nautical miles or about a day of constant steaming at 8 knots). This tidewater glacier discharges as much icy mass out to sea as does Petermann Gletscher or 79N Glacier to the north or half as much as Helheim, Kangerdlugssuaq, and Jacobshavn Glaciers to the south. Unlike all those other glaciers, Daugaard-Jensen and its fjord are still largely unexplored.

Location Map of Scoresby Sund. Kap Brewster is at bottom right while Daugaard-Jensen Gletscher 360 km away is near the top left.

Location Map of Scoresby Sund. Kap Brewster is at bottom right while Daugaard-Jensen Gletscher 360 km away is near the top left.

Part of the chart of the East Greenland coast drawn up by William Scoresby Jr. in 1822, showing the numerous features that he names in Liverpool land (Liverpool Coast) and adjacent areas. From: Scoresby (1823)

Part of the chart of the East Greenland coast drawn up by William Scoresby Jr. in 1822, showing the numerous features that he names in Liverpool land (Liverpool Coast) and adjacent areas. From: Scoresby (1823)

While the entrance between Kap Tobin and Kap Brewster was known to whalers in the early 19th century, it was William Scoresby Sr. after whom the fjord is named. His scientist son William Scoresby Jr. mapped coastal Greenland between 69.5 and 71.5 North latitude during his last voyage in 1822. Nobody entered the fjord until 1891 when Lt. Carl Ryder of the Danish Navy sailed deep into the fjord to explore the area for a year with 10 companions. They built a hut next to a natural port that they named Hekla Harbor. Amazingly, they also measured ocean temperature profiles almost every month from the surface to 400 m depth. I found these data at the National Ocean Data Center of the United States Government.

Ocean temperature (left panel) and salinity (right panel) as it varies with depth in different years. Blue represents measurements from 1891/92, red from 1990, and black from 2018.

Ocean temperature (left panel) and salinity (right panel) as it varies with depth in different years. Blue represents measurements from 1891/92, red from 1990, and black from 2018.

Searching for data from Scoresby Sund, I found 17 profiles of water temperature with data from at least 10 depths. Funny that 12 of these profiles were collected in 1891 and 1892 while the other 5 profile contain salinity measurements made in 1933, 1984, 1985, 1988, and 2002. The 1988 cast was taken by an Icelandic vessel and also contained continous data from a modern electronic sensor rather than waters collected by bottles. I “found” another 4 modern sensor profiles collected in 1990 at the Alfred-Wegener Institute in Germany.

That’s pretty much “it” … until we entered the fjord in 2018 when we collected another 27 casts thus more than doubling the ocean profiles. More exciting, though, is the very large shift in ocean temperatures from 1990 to 2018. The 1990 temperatures are very similar to the 1891/92 temperatures, but all old temperatures (also from 1933 and 1985, not shown) are all about 1 degree Celsius (2 degrees Fahrenheit) cooler than those we measured in 2018. Why is this so? Does such warming originate from outside the fjord? If so, how does the warmer Atlantic water at depth in deep water crosses the 80 km wide shallow continental shelf to enter Scoresby Sund? Are any of these ideas supported by actual data? What data are there?

Ocean data location off eastern Greenland collected from 1890 to 2010 that reside in NODC archives. Red are water bottle data while yellow are modern electronic sensor measurements. The white box bottom left is the entrance to Scoresby Sund. Light blue areas are water less than 500 m deep while dark blue shades are deeper than 1000 m.

Ocean data location off eastern Greenland collected from 1890 to 2010 that reside in NODC archives. Red are water bottle data while yellow are modern electronic sensor measurements. The white box bottom left is the entrance to Scoresby Sund. Light blue areas are water less than 500 m deep while dark blue shades are deeper than 1000 m.

Discoveries in science can be pretty basic, if one is at the right location at the right time with the right idea. Also, there is more data to the south that I did not yet look at to investigate the question of what causes the warming of bottom waters in Scoresby Sund.

EDIT Dec.-31, 2019: Replace “warmer” with “cooler” when comparing 1891 and 1990 (cooler) to 2018 (warmer) water temperatures.