Category Archives: Uncertainty

Is Petermann Gletscher Breaking Apart this Summer?

I am disturbed by new ocean data from Greenland every morning before breakfast these days. In 2015 we built a station that probes the ocean below Petermann Gletscher every hour. Data travels from the deep ocean via copper cables to the glacier surface, passes through a weather station, jumps the first satellite overhead, hops from satellite to satellite, falls back to earth hitting an antenna in my garden, and fills an old computer.

A 7-minute Washington Post video describes a helicopter repair mission of the Petermann data machine. The Post also reported first result that deep ocean waters under the glacier are heating up.

Sketch of Petermann Gletscher’s ice shelf with ocean sensor stations. The central station supports five cabled sensors that are reporting hourly ocean temperatures once every day. Graphics made by Dani Johnson and Laris Karklis for the Washington Post.

After two years I am stunned that the fancy technology still works, but the new data I received the last 3 weeks does worry me. The graph below compares ocean temperatures from May-24 through June-16 in 2017 (red) and 2016 (black). Ignore the salinity measurements in the top panel, they just tell me that the sensors are working extremely well:

Ocean temperature (bottom) and salinity (top) at 450-m depth below Petermann Gletscher from May-25 through June-16 2017 (red) and 2016 (black). Notice the much larger day-to-day temperature ups and downs in 2017 as compared to 2016. This “change of character” worries me more than anything else at Petermann right now.

The red temperature line in the bottom panel is always above the black line. The 2017 temperatures indicate waters that are warmer in 2017 than in 2016. We observed such warming for the last 15 years, but the year to year warming now exceeds the year to year warming that we observed 10 years ago. This worries me, but three features suggest a new ice island to form soon:

First, a new crack in the ice shelf developed near the center of the glacier the last 12 months. Dr. Stef Lhermitte of Delft University of Technology in the Netherlands discovered the new crack two months ago. The new rupture is small, but unusual for its location. Again, the Washington Post reported the new discovery:

New 2016/17 crack near the center of Petermann Gletscher’s ice shelf as reported by Washington Post on Apr.-14, 2017.

Second, most Petermann cracks develop from the sides at regular spaced intervals and emanate from a shear zone at the edge. Some cracks grow towards the center, but most do not. In both 2010 and 2012 Manhattan-sized ice islands formed when a lateral crack grew and reached the central channel. The LandSat image shows such a crack that keeps growing towards the center.

Segment of Petermann Gletscher from 31 May 2017 LandSat image. Terminus of glacier and sea ice are at top left.

And finally, let’s go back to the ocean temperature record that I show above. Notice the up and down of temperature that in 2017 exceeds the 2016 up and down range. Scientists call this property “variance” which measures how much temperature varies from day-to-day and from hour-to-hour. The average temperature may change in an “orderly” or “stable” or “predictable” ocean along a trend, but the variance stays the same. What I see in 2017 temperatures before breakfast each morning is different. The new state appears more “chaotic” and “unstable.” I do not know what will come next, but such disorderly behavior often happens, when something breaks.

I fear that Petermann is about to break apart … again.

How to Power Modern Economies: Read Your Meter

Read you meter at home. This fun-filled advice was given by Sir David MacKay in a wonderful TEDx talk about how we heat our homes, get to work, run our computers, and how it all scales across countries and continents. The idea is really about how we run our lives while also trying to pass on a livable planet to our grand-children without the politically correct “greenwash” and self-righteous “claptraps”. Read your meter, do some algebra, and embrace the adventure to explore your home, your life, and the energy it all takes. If you read this far, watch the movie

David MacKay taught physics and information theory at the University of Cambridge in England. I learnt of him via Ruth Mottram in one of her many tweets. Dr. Mottram studies climate impacts of Greenland glaciers and works at the Danish Meteorological Institute. The tweet made me buy the book “Information Theory, Inference, and Learning Algorithm’s” that David MacKay wrote a few years back. It arrived today.

What piqued my interest was the advanced math that goes into designing networks that send and transform information such telephone calls via wireless, computer networks, and how to deal with imperfect channels of communication. My marriage comes to mind, too, because what I say is not always what I mean which is not always what my wife hears and vice versa, but I digress. Imperfect communication channels are one challenge we will face in an experiment to explore acoustic underwater data transmissions that hopefully will take place next year out of Thule Air Force Base, Greenland. Water and ice are imperfect communication channels that we need to use wisely to make our whispers carry far. Try to talk to a person across a busy street in Manhattan with all its hustle and bustle; you need to find something smarter and more effective than just simple shouting.

David MacKay wrote a second book that is close to his TEDx talk and is called “Sustainable Energy without the Hot Air.” Experimenting at home like any good physicist does, he discovers that “… the more often I read my meter, the less gas I use!”

There is so much more to this man, his work, and ideas as a physicist with a keen interest in the big picture without skipping the details. Sadly, he died yesterday of cancer too early only 48 years of age.

Accidental Careers: Oceanography and Marine Engineering

A student at a vocational High School in Tulsa, Oklahoma asked me three questions today about my career choices as he ponders his’ in Marine Engineering

1. If you had to do anything over, related to your career or education, would you do anything differently?
2. What advice would you give to me as someone interested in pursuing a career path similar to yours?
3. How many coworkers or workers do you work with on average in your job position?

that I answered as follows

The author working at sea in 2003 or 2004. [Photo credit: Chris Linder, WHOI]

The author working at sea in 2003 or 2004. [Photo credit: Chris Linder, WHOI]

1. No.

2. Follow your passions; do what you enjoy doing; try new things; don’t be afraid to make mistakes, but learn from them; find people who share your passion and try to work with them.

3. It varies, let me add it up the people I had direct contact with the last 10 days; 2 scientists in Sweden plus 2 scientists in England, plus 2 scientists in Oregon, plus my 2 PhD students, plus 3 UDel colleagues all to prepare for two expeditions this summer to Greenland and Alaska; plus 3 UDel administrators, plus 1 undergraduate in a class, plus 5 professors on a budget committee to teach and help run the university, plus 1 person in California (fund-raising), plus 1 colleague in New York (writing papers), plus 2 engineers in Massachusetts (instrumentation), plus 1 sales manager in California (cable design), plus my wife for moral support, stress relief, and discussions … that adds up to about 26 people.

As your first question did not really count, I do add a personal comment on careers and career choices:

We all have only one past that we cannot change, but the future is always wide open with infinite new possibilities, new opportunities, and new people that all too often we cannot imagine or plan for ahead of time. For example, I grew up in a family in Germany where NOBODY on either my mom’s or my dad’s side of the family ever finished High School. As a result I had no idea what one does with High School (I wanted to become a paratrooper at 16, an anarchist at 18, a student at 20, a nurse at 21, etc.), what one does with a university degree, what one does after a PhD, etc. I always enjoyed reading, learning, and traveling, but it was unimaginable to me that this could lead to a job or career. Thirty years later I am still in awe and stunned by it. I did neither know nor touch computers until I left Germany for Britain at age 26. Now 90% of my work is writing and coding on a range of computers. Most things along my specific career path happened by chance and pluck, some bad, but mostly good. This is why item #2 above is so important. Passions and people also change over time, and so do we.

Thank you for the questions, Hunter.

Heartbeat of Ocean and Air of Greenland

While cables are designed at a small company in southern California,while instruments are shipped to friends at the British Antarctic Survey in England, while instrument locations are contemplated by a small group of scientists, technicians, and graduate students, I am also on a journey back in time to check up on the heart beat of the air we breath and the oceans we sail. The Arctic heartbeat to me is the annual change from the total darkness of polar night to total sunlight of polar day. This cycle, this heartbeat takes a year. There is 24 hours of day in summer the same way that there is 24 hours of night now. Let me first show, however, where we are heading before I look at the heartbeat.

I love making maps and this is a rich and pretty one that shows North America from the top where Petermann Fjord and Glacier are (tiny blue box on left map). The colors are water depths and land elevations. The thick dotted red line is where a very large iceberg from Petermann traveled within a year to reach Newfoundland. Teresa, one of the contributors to my crowd-funding project, sailed up there to Newfoundland to see this iceberg. And she made a movie out this voyage. So, what happens up there in northern Greenland only takes a year, maybe two, to reach our more balmy shores. What happens in Greenland does NOT stay in Greenland. Vegas, Nevada this is not.

Figure1

Now on to the map on the right. This is the tiny blue box made much larger. It looks like a photo, and in a way it is, but a photo taken by a satellite, well, only one “channel” of this specific satellite, the many shades of gray are mine, it is NOT the real color. The glacier is in the bottom right as the white tongue sticking out towards 81 N latitude. Red lines there are water depths of 500 and 1000m. The blue dot in the top-left is where I had to leave an ocean sensor in a shallow bay for 9 years, because we could not get there to retrieve it for 6 years. Lucky for me (well, some smart design helped), the instrument was still there, collecting and recording data that we knew nothing about for 9 long years. It took smart and hardy fishermen from Newfoundland aboard the CCGS Henry Larsen to dangle my sensor out of the icy waters. And here is the heart beat it revealed:

AlertDiscTemp

Top graph is ocean temperature, bottom panel is air temperature nearby. And as you go from left to right, we move forward in time starting in 2002 until the end of 2012 when the last ocean measurements were made. The red lines are a linear trend that represents local (as opposed to global) warming. Both go up which means it gets warmer, but careful, the bottom one for air is no different from a straight line with zero slope meaning no warming. It does go up, you say correctly, but if I do formal statistics, this slope is no different from zero just due to chance. The top curve for the ocean, however, is very different. It does not look different, but the same statistics tell me that the warming is NOT due to chance alone. Oh, in case you wondered, the two dashed lines in the top panel are the temperatures at which seawater freezes and forms ice for the salinity range we see and expect at this embayment. As you add salt to water, it freezes at a lower temperature. This is why we put salt on our roads in winter, it makes the water freeze less fast.

I am a doctor, so here is my conclusion: Ocean heart beat is a little irregular and the trend is not good news for the ice. Air heart beat looks normal, the trends may need watching, but I am not too worried about that just yet. Watch the oceans … that’s where the heat and the action is these days.

Men and Women on the Edge 1

EDIT: Original post was too long and rambling. One advice by wise female council, I decided to turn this into two separate posts. This is the first. July 5, 2014.

The “Quiet American” is not a popular book in the United States of America, but to me it described the dilemma and dangers of being American very well. Continue reading