Arctic Ocean AXCTDs NPEO-IPY and Beyond

The National Science Foundation's International Polar Year (IPY) 2007-2008 Initiative supported the extension of the NPEO 2008 North Pole hydrographic survey to cover the Beaufort Sea by Twin Otter skiplane. Fifteen CTD-Chemistry surface stations were obtained in late March across the southern Beaufort in unusually cold air temperatures, to add to the 20 stations then recorded near the North Pole during April. The new, digital Airborne eXpendable Conductivity, Temperature, and Depth probes (AXCTD) manufactured by The Tsurumi-Seiki Co., LTD. suggested a means to extend the IPY Beaufort coverage farther north than was reachable from northern Alaska in the skiplane. A second Twin Otter on standard (thin) wheels and with dual, long-range ferry tanks flew two days in mid-April north from Deadhorse, seeking to drop AXCTDs into open leads, and record the ocean profiles without landing. The relatively smooth, uniform ice cover with persistently cold air temperatures presented few cracks new enough to be feasible drop targets, especially in the northwest Beaufort, but eight successful CTD profiles were obtained and are offered here. This project was supported by NSF Grants ARC-0634226, OPP-9910305, and OPP-0352754.