Author Archives: Andreas Muenchow

Greenland Glacier-Driven Ocean Circulation

Greenland’s coastal glaciers melt, shrink, and add to globally rising sealevel. They also drive local ocean currents that move icebergs around unless they are stuck on the bottom. The glaciers’ melt is cold fresh water while the adjacent ocean is both salty and warm. Checking on what we may expect against observations, I here use data from NASA’s Ocean Melts Greenland initiative that dropped ocean probes from an airplane into the ice waters off coastal Greenland to measure ocean temperature and salinity.

For six years these data show how the coastal ocean off Greenland varies from location to location next to glaciers as well as from year to year. More specifically, I picked Melville Bay in North-West Greenland for both its many glaciers and many dropped NASA ocean sensors. The ocean data allow me to estimate ocean currents by using a 100 year old physics method. I just taught this to a small class of undergraduate science students at the University of Delaware. My students are strong in biology, but weak on ocean physics. This essay is for them.

Melville Bay is a coastal area off north-west Greenland between the town of Upernavik (Kalaallisut in Greenlandic) near 73 N latitude where 1100 people live and the village of Savissivik (Havighivik in Inuktun) at 76 N latitude where 60 Inuit live. There are no other towns or settlements between these two villages that are about as far apart as Boston is from Philadelphia, PA. Imagine there were no roads from Boston to New York to Philadelphia but only one large glacier next to another large glacier. This is Melville Bay.

Below I show an excellent set of photos of Savissivik by a French husband and wife team who visited in 2013/14. Their photographic gallery captures elements of contemporary subsistence living in remote Greenland where animals like seals, birds, fish, narwhal, and polar bears provide food, fuel, clothing, and income.

NASA dropped some 50 ocean sensors into Melville Bay froma plane during the short summer seasons each year 2016 through 2021. I met NASA pilots, engineers, and scientists doing their experiments when I was doing mine from a snowmobile in April of 2017 and again with Danish friends from a Navy ship in August of 2021, but these are stories for another day.

Let me start with a map of where NASA dropped their ocean profiling floats into Melville Bay and thus introduce the data. While the surface waters are usually near the freezing point, waters 300-400 meters deep down are much warmer. They originate from the Atlantic Ocean to the south and one of the goals of NASA’s “Ocean Melts Greenland” campaigns was to determine if and how these Atlantic waters reach the coastal glaciers. Most glaciers of Melville extend into this warm ocean layer and thus are melted by the ocean.

In the map above I paint the maximal temperatures in red and the bottom depths in blue tones. The profile on the right shows data for all depths at one station. As salinity increases uniformly (red curve) the temperature increases to a maximum near 300-m depth (black curve). It is this maximal subsurface temperature that I extract for each station and then put on the contour and station map on the left. The straight blue line connects Upernavik in the south with Sassivik in the north. It is an arbitrary line, coast-to-coast cutting across Melville Bay.

The warmest warm waters we find near Upernavik in the south and within a broad submarine canyon that brings even warmer waters from Baffin Bay towards the coast. Temperatures here exceed 2.4 or even 2.7 degrees Celsius. Most coastal waters along Melville Bay have a temperature maximum of about 1.5 to 1.8 degrees Celcius (about 35 Fahrenheit) and this “warm Atlantic” ocean water melts the coastal glaciers. The ocean melts the glaciers summer and winter while the warm air melts it only in summer.

There is more, because the glaciers’ melt also discharge fresh water into the ocean where it mixes to to form a layer of less dense or buoyant water. The buoyant waters create a local sealevel that is a little higher along the coast than farther offshore. The map above indicates that this “little higher sealevel” comes to about 4 cm or 2 inches. If this pressure difference across the shore is balanced by the Coriolis force, as it often does, then an along-shore coastal current results. This coastal current would move all icebergs from south to north unless they get stuck on the bottom. Along the northern coastline of Melville Bay the surface flow is from east to west. The coastal current is strongest near Savissivik where we find a (geostrophic) surface current larger than 40 cm/s. At that speed an iceberg would move more than 21 miles per day. Such strong surface flows are exceptional and diminish rapidly with depth. Hence a freely floating iceberg with a draft of several hundred meters would move much slower than the surface current.

I met a hunter from Savissivik in April of 2017 and for a fast-moving night we discussed the state of local fishing, hunting, living, traveling, and working on the sea ice next to the glaciers of Melville Bay. He invited me to become his apprentice. As such I would now ask him about the surface currents outside his home. Which way does he observe the icebergs to move in summer or winter? Has hunting on the sea ice in winter changed over his life time? When is it safe to travel there with a dog-sled? Could he and I perhaps work together during the spring to deploy ocean sensors through the sea ice? I am dreaming again …

My own private Iceland

Reading Halldor Laxness’ epic novel “Independent People,” I am in Iceland for the last 10 days. I re-discovered this author after reading a small essay the New Yorker published last week. This book is set in Iceland of the early 1900s to the mid 1920ies. Sheep, starvation, and spirits evil and otherwise all play roles as does time that changes people, politics, and procreation. Finishing it sunday, I feel I have been here before.

Lifted from fioncchu,

My first Laxness novel “Islandklukken” (Iceland’s Bell in English) I read as a 20-year old during the Cold War when I served my country for 16 month more than 40 years ago. At the time I dreamt of the world as it had not yet revealed itself to me. My pre-college mind had a romantic notion of walking remote and wild areas of Norway and Iceland after an unromantic 1981 motorcycle trip across southern Norway the prior summer. I now worked as a paramedic in the drizzly gray German town of Husum by the North Sea. During this first winter away from parents and High School friends I bought my first Laxness and immediate afterwards “Die Saga von Egil” (Egil Skallagrimsson Saga). This Icelandic saga was written about 1200 AD and it chronicles the life of a viking poet farmer who killed many men for the 91 years after his birth in 904 AD. Along with this book I also bought a topographic map of Iceland published by the Touring Club of Iceland at a scale of 1:750,000 printed in 1979 in Reykjavik. It cost me 29.90 Deutsche Mark or about 10% of my monthly income at the time. Such armed, I followed Egil Skallagrimsson across Iceland starting at his place of birth about 35 miles north of Reykjavik.

Oil on canvas: “Summer in the Greenland coast circa the year 1000” painted by Danish painter Carl Rasmussen in 1874.

The same map follows me on my current travels across Iceland until I find the many databases of the Icelandic Geodedic Survey. High-resolution (1:50,000 scale, say) are generated instantly whereever I want. For days now I am hiking for days across the Icelandic highlands in the East and West, across interior deserts in the center, and wet coasts in the North. My first trip was across the Highlands from Pingvellir to Reykir past the glacier Langjoekull to the North and West and the glacier Hofsjoekull in the East and South. My maps locate many backcountry huts where I stay or pitch my tent. I here follow Dieter Graser’s excellent descriptions, photos, and GPS waypoints when he hiked the “Kjalvegur” alone in 2007. I even stole this map from his content-rich web-site where I spent the last 2 days traveling with finger on maps, books, and internets

Dieter Graser’s hike from Pingvellir in the south-west to Maellfell near Reykir in the north-east. It took him 19 days to complete this hike in August of 2007. [Credit Dieter Graser]

I even got a first intinary: My direct Iceland Air flight leaves Baltimore on Aug.-16 at 8:30 pm in the evening and arrives in Reykjavik the next morning at 6:25 am. A Grey Line bus gets me into the Highland for less than $48 in 2 1/2 hours, but it does not leave until 8 am on the next day. Hence there is plenty of time in iceland’s capital city to explore, get provisions, and perhaps visit the Landsbjoerg which is Iceland’s Search and Rescue organization. It is good practice to let someone local know when you will be where and back as one heads into the backcountry. The bus will let me off in Hviternes from where it is a 40 km hike to Hveravellir where there are two web-cams: the first points to the West while the second points East. I got 5 days to do this 3-day hike, so there is time for a day or two to do nothing, read, or just soak in the scenery and/or a hot spring and/or both at the same time. The bus will pick me up at the hot springs of Hveravellir at 2:30 pm on Aug.-22 to get me back to Reykjavik at 7:30 pm which is plenty of time to catch my plane back home the next day at 5:10 pm with an arrival 6 hours later. The return flight comes to $746 and even includes my backpack (<50 lbs).

There is just one problem … my passport expired.

P.S.: The three photos below are all from Dieter Graser who shared them at his outstanding web-site at

The hut Þverbrekknamúli along the “Kjalvegur.” The view is to the east with the Kerlingarfjöll in the back. [Credit Dieter Graser]
Dieter Graser at Hvítárnes in 2007. [Credit Dieter Graser].
Hveravellir in August 2007. [Credit Dieter Graser]

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, Oct.-13, 2021]

Election Work during a Pandemic

Elections are messy, but patterns emerge. Elections have consequences, but people learn. Elections make news, but do we all know how they work? I did not and thus decided to learn. I served as a sworn-in Election Clerk in the State of Delaware this week to collect first-hand experiences. I wanted to decide for myself rather than just “believe” or “dismiss” abundant disinformation propagated by Russian and American troll farms on social media. I wanted to answer for myself, if the American election system is safe, fair, and secure. My answer is a resounding yes for New Castle County, Delaware.

My badge for the Sept,-15, 2020 Closed Primary Election in New Castle County, DE, USA.

Any registered voter can apply to serve at a polling station as an Election Clerk, Judge, or Inspector:

The State of Delaware needs more than 4,500 registered voters to work in polling places for the General Election. This is a unique opportunity to serve your community by participating in the electoral process!

Pay comes to about $10 per hour for a 19 hour commitment. Students enrolled at a university in Delaware and local High School students older than 16 can apply as well. Within a week of mailing my application I was assigned a date and location for both a 4-hour training session and an election. I worried about the many, usually elderly election workers during our current Covid-19 pandemic. I took a calculated risk, but our democratic system by the People for the People requires the People to actually run the elections. Random citizens working the polls on Election Day are one check on State Governments who organize the elections.

Election Day started at 6 am to set-up computers, machines, and voter information in the gym of a local Elementary School. The first voter appeared at 7 am sharp while the last voter left shortly after 8pm. I left the school at 9 pm after votes were tallied, results were signed by each of poll workers and posted at the school. Multiple signed copies of votes and results were delivered by different people to different officials and offices. This includes both electronic and paper copies of each vote. I was home at 9:15 pm, exhausted, sore, and tired. A Samuel Smith’s Imperial Stout helped me to end the day happy, proud, content, and with many stories to share.

The best part was a wonderful, random, fun, and most diverse group of 11 poll workers. We ranged in age from 21 to 75 (or so), almost evenly split male/female, black/white, college/non-college, etc. and all with a refreshing sense of humor and purpose. One of us was a pastor, a postal worker, a home-maker, two professors, a school psychologist, a teacher, and we had at least three grand-parents. About 540 people came in to vote, only one person tried (and failed) to cheat by voting twice. He tried to vote in-person after he had mailed-in his absentee ballot which the State received already. He was politely told to leave which he did quietly. Perhaps he just tried to test the system, or he just forgot that he mailed his ballot, or he just listened to a paranoid and ignorant politician who told people to vote early by mail and then try to vote again in person. Either way, nobody voted twice.

Example of a mask violating Delaware’s Electioneering Laws, if worn inside a polling place.

We only had 3-4 people who tried to violate State Electioneering Laws (Del. Code Ann. tit. 15, §4942(a); (d)) by displaying partisan buttons, masks, hats, or t-shirts inside the polling place. This is illegal in Delaware and elsewhere; so please do not bring Biden/Harris or Trump/Pence buttons or similar partisan apparel or clothing to the the polling place. The “Electioneering” link is from the bipartisan National Association of Secretaries of State. Interestingly, all three “electioneers” were angry, white, male, 45-60 years old, and affiliated with the same party. They represented less than 2% of that party, but the three men succeeded in causing drama, emotional turmoil, and disruptions both inside the polling place and afterwards. I will fight for them to express their views as guaranteed by the U.S. Constitution, but their freedom of speech is limited inside the 50 feet diameter of the polling place during the 13 hours that people vote there. Several U.S. Supreme Court decisions back this view.

Only one person did not wear a mask, but this was my fault. He entered with a mask that carried in large letters a partisan political statement not allowed inside the polling place. When called on this by an Election Clerk he got angry and started to argue, but he was happy when I told him that he did not have to wear as mask that he promptly took off. [It was my mistake to tell him that not wearing a mask does not disqualify him from voting.] I asked to handle this person and borrowed the crutches of our oldest poll worker (with her permission) to use as a “teaching prop” of the 6 feet distance that I needed. He co-operated nicely and I thanked him for his important participation in an important process.

A more positive experience for me was to see how diverse my local community is. People of all colors, genders, ages, handicaps (both physical and mental) gave me a new perspective on who lives in the same town with me. I noticed an especially happy and celebratory atmosphere of the many black women of all ages who often came with their teenage sons and daughters to vote also. Many couples had different party affiliations and got along just fine. Kids came, too, as their parents voted and show them how its done. There is Hope and Strength in Diversity.

Stained glass window by Dragonfly Leathrum

As a skilled physical scientist and computer geek, I conclude that it is almost impossible to “cheat” on the actual vote both for absentee (often called mail-in) or in-person ballots. I also conclude that Russian and American trolls and politicians try to suppress, manipulate, and disrupt the vote by spreading lies and disinformation to create doubt and confusion. The threat becomes real, if we the People believe and spread such lies. Our voting system has evolved over more than 200 years. It is secure as (a) both electronic and paper copies of each ballot exist; (b) all containers, machines, and access points are sealed, documented, and traced; (c) custody of all materials is transparent with multiple checks; and (d) it is random People like you and me who run the nitty-gritty of elections. The process is transparent and open to anyone willing to spent 4 hours of training and 14-15 hours on Election Day.

P.S.: I had myself tested for Covid-19 this morning. The sore throat and cough probably resulted from talking to more people than I have seen the last 7 months and breathing through a mask for 15 hours straight.

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: