Switchyard UW CTD data

The Switchyard project is a program to study circulation (sea ice and upper ocean) in the region between Alert (Ellesmere Island) and the North Pole, through a series of annual springtime hydrographic surveys, moorings, and sea ice analyses. These UW CTD data were collected using a combination of helicopters and Twin Otter aircraft. In 2003-2006, data were collected by helicopter landing on the sea ice near a lead, where a small winch was used to lower a Seabird SBE 19plus CTD (with dissolved oxygen sensor) down to 500m. Data were collected on a SW-NE section across the continental slope centered at about 65W, 84N, and also at other locations in the Lincoln Sea as the opportunity presented itself. In 2007, poor weather conditions precluded safe helicopter operations and no UW CTD data were collected. Beginning in 2008 and continuing through 2012, a Twin Otter was used by the UW team to collect CTD profiles as deep as 1000m within a 500 km radius of Alert. In 2010 and 2011, Airborne Expendable CTD Probes were dropped into open leads from the Twin to record an ocean section across the north end of Nares Strait.