First sensors for future Petermann Gletscher Observatory, Greenland

Two ocean sensors arrived from Germany where I used them last in an experiment off the coast of Greenland last year. I bought them in 2002 and they have been in Arctic waters most of the time where they measure ocean temperature and conductivity very accurately a few times every second. Conductivity of seawater is what oceanographers measure when they want to talk about salinity and Arctic oceanographers must know salinity if they want to talk about ocean density. Water from cold melting ice and glaciers is less dense (because it is fresh) than the warm and salty water from the Atlantic Ocean that does the melting. You need heat to melt ice, but the heat that melts Greenland from below by the ocean comes from the Atlantic. The heat is at depth 200-400 meters deep, because of salt in the water that makes it dense and sink.

Oceanography and physics are fun, but here are the photos of what I work with over the weekend at home … maybe in my garden, too, to practice for the Arctic deployment, you may even watch me do it on the web-cam in my garden pointing towards the heated bird-bath. Geeks at play, science is fun:

Two SBE37sm with one set of 12 lithium batteries.

Two SBE37sm with one set of 12 lithium batteries.

The housing of these two instruments are rated for 7,000-m depth, I will have to install the lithium batteries ($4.80 for a single AA battery); each instrument needs 12 of those. Since 2003 we deployed a number of these in the Arctic where they collected data for over 3 years every 15 minutes. One of my students, Berit Rabe now works in Scotland and her dissertation and peer-reviewed publication was based on data from a single 2003-06 deployment of about 20 such instruments.

SBE37sm connect via RS-232 cable to the serial port of an old Dell computer.

SBE37sm connect via RS-232 cable to the serial port of an old Dell computer.

The instruments connect via a serial cable to the computers. In the past I had problems with instruments bought 12 years ago, because computers develop faster than oceanographic instrumentation. So, new is not always better, so I bought an old Dell Windows XP machine on e-Bay for $200 (actually I bought 2) to make sure that my sensors match software, CPU, and operating systems of the time that the instruments were bought. In order to “talk” to the sensors, I will need to put the lithium batteries into them. I am very much looking forward to do this over the weekend.

To be continued …

Note: This is a lab-note from my crowd-funding experiment at

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