Frozen Surveys

Knudsen 320 Series Echosounder Provides Critical Global Warming Data

December 12th, 2005

Examples of Healy’s Knudsen chirp sonar (center frequency 3.5 kHz) records showing (a) glacial erosion and probable glacially deposited diamictons on Northwind Ridge and (b) pockmark collapse structures, perhaps caused by gas escape from possible methane buildups in the sediment on Mendeleyev Ridge as well as uniform sediment drapes. Data was processed using Sioseis software.

The recently completed Healy-Oden Trans-Arctic Expedition 2005 (HoTrAX’05), gathered critical data using their 320 series Knudsen Echosounder. The expedition retrieved 29 piston cores averaging nearly 12 meters in length from a complete transect across the central Arctic ocean. These cores provide a critically-needed sample cache for both a pan-Arctic stratigraphy and a long awaited paleoclimate record that it is hoped will greatly improve the understanding of how deepwater is exchanged between Arctic basins, how the climate system in the Arctic works over longer time intervals, and how the Arctic system interacts with global systems. The coring was done from the U.S. Coast Guard Cutter (USCGC) Healy, while oceanographic measurements were made from the Swedish icebreaker Oden.

Click here to download the full article (in PDF format) published in the December issue of EOS.