The International Polar Year (IPY) is now in full swing. Led by Hajo, our group is heavily involved in SIZONet ( Seasonal Ice Zone Observing Network) to make and coordinate sea ice measurements in the seasonal ice zone. The seasonal ice zone is the area where ice is not present year round, but grows in the winer and melts in the summer. This is a usual cycle for much of the western and northern Alaska coast. Hajo, Matt, Jonas, Malcolm Ingham and myself were all up there sometimes between April 4 – April 16.
More than just our group, this was a coordinated effort in Barrow with many visiting groups converging to make measurements on both the landfast ice attached to shore, and to use helicopters to access off-shore ice. A central interest was ice thickness measurements. On an Arctic scale, satellites can image the area of sea ice, but not the depth, so extra measurements are needed to monitor sea ice thinning and its change in total volume. Regionally, thickness measurements are useful to determine whether or not ice ridges are grounded on the sea floor, providing additional stability to the ice. Barrow is a good meeting point for these two interests, and we had a mix of experienced operators of established devices and researchers new to sea ice with developmental devices.
Stefan Hendricks from (AWI )( the Alfred Wegener Institute, for German Polar and Oceanography Research) was back in Barrow again. Stefan was operating his `EM bird`, a torpedo-like device slung from helicopters to measure ice thickness using a process called electromagnetic (EM) induction. The bird generates an oscillating magnetic field (4 kHz), which induces currents in the ice and water below, which in turn generate secondary magnetic fields. The bird measures the total response, from which Stefan can determine the position of the bottom of the ice. This is because the salty sea water is much more conductive that ice, so the secondary fields are dominated the bird basically measures A laser altimeter measures the height above snow, and the difference is the total thickness of snow + ice. Stefan has operated all over the Arctic and Antarctica – but hopes to finish his PhD soon!
Malcolm and I again made DC electrical resistivity measurements using surface arrays and 4 strings frozen into the ice back in January. Armed with a new, automated system, we were much faster, warmer and happier than previous trips of laborious manual measurements – which nevertheless did lay the groundwork for the current measurements.
Brent Nowak and his student Austin Derric were up from San Antonio Texas to field-test an ROV (Remotely Operated Vehicle) for under ice photography and videography. It seemed like a very valuable trip for them – a lot of things can (and did) go wrong at -20 C that you wouldn’t anticipate in Texas. They were never flustered, and it would be nice to see them back in Barrow later on. Under ice images are really cool and it would be need to inspect the grounded ridges in Barrow that anchor the landfast ice in place.
Mike Lewis and Blake Weissling were also up from Texas for field testing. Their instrument is a multi-frequency EM device and they were calibrating and field testing. Blake has the dubious distinction of being on two research boats on which fires have broken out.
Matt Druckenmiller continued his work mapping local whaling trails. Each spring these snow machine trails are cut through rubble fields of ice to the preferred position at the ice edge of each whaling captain. Matt collected more than 40 km of thickness measurements by walking these trails with a surface-based version of the EM bird (Geonics EM-31). A real highlight of the trip for me was joining Matt and Lewis Brower to cut trail one night, then heading back to his Dad’s house for hot tea. Lewis is the Logistics Coordinator at BASC and the youngest son of esteemed whaling captain Arnold Brower Snr, who is lithe, extremely knowledgeable and very sharp at 84 years old and still hunts by himself 100 miles from town. He was preparing whaling equipment when we visited at 11pm and over tea and cookies shared stories and insights.