Tag Archives: underwater acoustics

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.

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.

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