2003 Helo Survey ISUS Nitrate Concentrations, Temperature, Salinity, and Density [Christensen, J. and H. Melling]

As part of the Shelf-Basin Interactions (SBI) project, early spring sampling was performed in the eastern area of the SBI study area using aircraft. Flights began on 1 April 2003 and finished on 15 April. During this time, we sampled 42 sites (49 Conductivity Temperature Depth (CTD) casts) on a series of 5 transect lines which bracketed and were parallel to the SBI current meter mooring line located at 152 W longitude. Stations were about 10 km apart along each transect line. A map of the achieved sampling sites is available (file: Sw3loc4a.pdf) and station locations, sampling dates and times are found in the file, Sw3vit-4.csv. At sites 10 through 49, a Seabird CTD (SBE-25) and Satlantic In-Situ Ultraviolet Spectrophotometer (ISUS) nitrate analyzer with a water sampling bottle was deployed through an 8 inch hole augured through the pack-ice. Continuous profiles of pressure, temperature, salinity, and ISUS-sensed nitrate concentrations were made from the ice hole to either the sediment surface or to about 390 m. The ISUS was not used at CTD casts 1 through 9. CTD data were processed with Seabird software (Seasoft) and the data binned into 0.5 dbar layers. All basic CTD data are contained in another dataset as well as the nutrient data collected from the water sampling bottles. The ISUS samples at a relatively slow rate (3.5 Hz), and even though repeated vertical profiles were collected at each site, not all pressure bins contained ISUS measurements. Data herein include basic CTD data as well as the ISUS data (in its respective bin) converted to nitrate concentration, and the continuous ISUS nitrate profiles constructed by linearly interpolating binned data between two vertically adjacent ISUS averages. A complete description of the evaluation procedure for these ISUS data is being prepared for publication, so data herein are considered to be in draft form. The data are in csv format.