Circulation in the Freshwater Switchyard of the Arctic Ocean: Helicopter CTD Profile Data 2003-2005The Freshwater Switchyard of the Arctic Ocean (FSAO) project includes a helicopter based at Alert on northern Ellesmere Island to carry out oceanographic surveys northward across the shelf break in late spring. The 'freshwater switchyard' is a region to the north of the eastern Canadian Archipelago and Greenland that is hypothesized as a bifurcation point for freshwater transfer between the Arctic and North Atlantic Oceans. Measurements were made in April and/or May of 2003, 2004, and 2005 using a Seabird SBE 19plus Seacat internally recording CTD instrument with an SBE 43 dissolved oxygen sensor. Data include depth, pressure, temperature in situ, potential temperature, conductivity, salinity, and density. 2003 and 2004 data also include dissolved oxygen; in 2005 the oxygen sensor failed. Each cast reaches about 500 meters unless the ocean depth at that position is less. Further information and photography from the 2005 survey are posted at the project Web site, The Freshwater Switchyard of the Arctic Ocean (http://psc.apl.washington.edu/switchyard/index.html). Data are in space-delimited ASCII format, and are available via FTP. The FSAO project is a program to study freshwater circulation (sea ice and upper ocean) in the 'freshwater switchyard' between Alert (Ellesmere Island) and the North Pole, through a series of annual springtime hydrographic surveys. These surveys are intended to measure the eastward-flowing boundary current and also determine water property changes that occur in the transition from the deep Arctic Ocean basin to the shallow continental shelf. These data represent the first three years of surveys in 2003-2005; additional surveys are planned through 2007.
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