Tag Archives: physics

Greenland Glacier Ocean Warming

The Swedish icebreaker Oden will visit Petermann Fjord in northern Greenland in 6 months time. The US National Science Foundation (NSF) funded a large geophysical and geological experiment after excruciating peer-review over a 4-year period. The experiment shall reveal climate histories from sediment cores, geomagnetics, and both bottom and sub-bottom sonar profiling. Besides this main mission Oden also supports several smaller auxiliary projects some of which are funded by NSF while others are not. It will be a fine collaboration between Swedish and American scientists working together in perhaps one of the most difficult to reach and beautiful places on earth.

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 towards the south-east across Petermann Fjord with Petermann Gletscher to the left (east). [Photo Credit: Erin Clarke, Canadian Coast Guard Ship Henry Larsen]

I will aboard the ship to deploy sensors some of which exist and are funded while others are neither. Let me outline first the funded part and then part where you the reader and I can perhaps join forces. First, we will test first elements of an underwater acoustic communication system. Think cell-phones, except the phone towers are under water where they are called modes. The modems talk to each other by sending sound back and forth the same way that whales do talk to each other.

Here is a narwhals sound

that you can use as a ringtone, credit goes to Voices of the Sea web-site at Scripps Institution of Oceanography. These whales visit Petermann Fjord in summer and we saw many of them frolicking in August of 2012 when I visited the area with the Canadian Coast Guard whom I credit for these photos:

Our man-made sound is very quiet, but because it is quiet, it only moves 3-10 km through the water. To increase our range, we plan to install several quiet sound sources that whisper from one water-phone (=hydrophone) to the next. The goal is to get data from ocean sensors moved along this whispering system of underwater “cell phones” to reach a listening station that we plan to install at the edge of Petermann Gletscher’s floating ice shelf. The ice is 200 meters or 600 feet thick and it is not trivial to drill through that much ice, but it can be done, and the British Antarctic Survey is aboard with a team of experts to do so to get sediment cores from the bottom below the ice:

Makinson1993-Fig04

Today I ordered a first cable that will connect the underwater modem hanging under the 200-m thick ice to the surface where a fancy computer connects it to the internet via to a satellite phone. All data calls that the underwater listening station receives will move up the cable to the glacier surface and on to us all via the internet. This challenging engineering project is funded, but I like to use the same hole, computer, and satellite link to get additional ocean and air data.

Additional stations will be drilled through the ice-shelf farther inland to reach the ocean also. Here we also need cables and instruments that tells us how the glacier is melted by the ocean at different location along its 50 km long floating ice shelf. The incremental costs are small relative to the cost of getting a ship and helicopters there, but NSF cannot easily fund small projects rapidly. It takes a long time to pass scientific peer review. This is where you, my dear reader come in: I need your help to raise $10,000 to add science and observations to an engineering feasibility study that is the underwater whispering sound system.

The motivation and details are described with videos, pictures, laboratory notes, plots, ideas, as well as some short, quirky, yet technically correct descriptions at the crowd-funding site

https://experiment.com/projects/ocean-warming-under-a-greenland-glacier.

I created and launched it today, it will be up for 30 more days. If you can and if you like the science, work, and fun that I describe on these pages, please consider making a small donation. You have the power to make this happen and I will share all data both from below and above the ocean and glacier surface with you.

As a physicist, gardener, teacher, writer, traveler, ping-pong player, and geocacher I am naturally curious about both our natural and social world. I love experiments and to me the crowd-funding at Experiment.com is a most enjoying experiment to connect to people in a new way. Full disclosure, however, this company takes 8% of all funds generated to supports its wonderful software and staff. Perhaps you like to join this experiment by spreading the word and, if you can afford it, help pay for some of the technology needed to bring Greenland and its mysteries to everyone who wants to connect to it.

Changing Weather, Climate, and Drifting Arctic Ocean Sensors

Three people died in Buffalo, New York yesterday shoveling snow that arrived from the Arctic north. The snow was caused by a southward swing of air from the polar vortex that is all wobbly with large meanders extending far south over eastern North-America where I live. Physics deep below the thinly ice-covered Arctic Ocean hold a key on why we experience the Arctic cold from 2000 km north and not the Atlantic warmth from 100 km east.

A wobbly jet stream that separates cold Arctic air from warmer mid-latitude air. Note the strong gradients over eastern North America. [From wxmaps.org]

A wobbly jet stream on Nov.-19, 2014 that separates cold Arctic air from warmer mid-latitude air. Note the strong differences over eastern North America and how balmy Europe, Russia, and Alaska are. [From wxmaps.org]

The Arctic Ocean holds so much heat that it can melt all the ice within days. The heat arrives from the Atlantic Ocean that moves warm water along northern Norway and western Spitsbergen where the ocean is ice-free despite freezing air temperatures even during the months of total darkness during the polar night. As this heat moves counter-clockwise around the Arctic Ocean to the north of Siberia and Alaska, it subducts, that is, it is covered by cold water that floats above the warm Atlantic water.

North-Atlantic Drift Current turning into the Norwegian Current that brigs warm Atlantic waters into the Arctic Ocean to the north of Norway and Spitsbergen. [Credits: Ruther Curry of WHOI and Cecilie Mauritzen of Norwegian] Meteorological Institute]

North-Atlantic Drift Current turning into the Norwegian Current that brigs warm Atlantic waters into the Arctic Ocean to the north of Norway and Spitsbergen. [Credits: Ruther Curry of WHOI and Cecilie Mauritzen of Norwegian] Meteorological Institute]

But wait a minute, how can this be? We all learn in school that warm air rises because it is less dense. We all know that oil floats on water, because it is less dense. Well, the warm Atlantic water is also salty, very salty, while the colder waters that cover it up are fresher, because many larger Siberian rivers enter the Arctic Ocean, ice melted the previous summer, and fresher Pacific waters enter also via Bering Strait. So, the saltier and more dense Atlantic water sinks below the surface and a colder fresher layer of water above it acts as a insolation blanket that limits the amount of ocean heat in contact with the ice above. Without this blanket, there would be no ice in the Arctic Ocean and the climate everywhere on earth would change because the ocean circulation would change also in an ice-free Arctic Ocean, but this is unlikely to happen anytime soon.

A single profile of temperature and salinity from an ice-tethered profile (ITP-74) off Siberia in July 2014. Note the warm Atlantic water below 150 meter depth.

A single profile of temperature and salinity from an ice-tethered profile (ITP-74) off Siberia in July 2014. Note the warm Atlantic water below 150 meter depth.

Some wonderful and new science and engineering gives us a new instant perspective on how temperature and salinity change over the top 700 meters of the Arctic Ocean every 6 hours. Scientists and engineers at the Woods Hole Oceanographic Institution with much support from American tax-payers keep up many buoys that float with the ice, measure the oceans below, and send data back via satellites overhead to be posted for all to see on the internet. Over the last 10 years these buoys provide in stunning detail how the Arctic Ocean has changed at some locations and has been the same at other locations. I used these data in an experimental class for both undergraduate and graduate students to supplement often dry lecture material with more lively and noisy workshops where both I and the students learn in new ways as the data are new … every day.

For well over 50 years the Soviet Union maintained stations on drifting Arctic sea ice that stopped when its empire fell apart in 1991. Russia restarted this program in 2003, but unlike the US-funded automated buoys, the Russian-funded manned stations do not share their data openly. No climate change here …

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 Continue reading

Fish, Fashion, and Climate: Simple Thoughts on Complex Systems

I love pickled herring, but the fashion of eating this delicacy varies with changing cultures and climates. In northern Europe it used to be a standard fare, perhaps still is, but in my native coastal North-Germany it was poor man’s food Continue reading

Petermann Ice Island Breaks while Plowing into the Bottom

The Manhattan-sized ice island that last year broke free of Petermann Gletscher in North Greenland plowed into the bottom and broke apart. Force equals mass times acceleration. When 18 giga tons (mass) of moving ice crashes into the ocean’s bottom 200 meters below the surface (acceleration), then something gotta give. And give it did, Continue reading