======================== Originally posted 2010-8-26 ============================= North Pole Environmental Observatory 2008 Expendble Current Profiles NSF Grants ARC-0909408 Sensitivity of Arctic Ocean Change to Background Mixing and ARC-0856330, OPP-9910305, OPP-0352754 North Pole Environmental Observatory XCP Drop 1 at CTD Station 5 Sta74_140W SerialNo. 8011044 2008-03-24/0159 UTC 74deg 02.36min North 140deg 18.67min West XCP Drop 2 at CTD Station 8 Sta75_150W SerialNo. 8021004 2008-03-26/2104 UTC 74deg 58.69min North 150deg 08.67min West XCP Drop 3 at CTD Station 10 Sta73_150W SerialNo. 8021009 2008-03-27/2054 UTC 72deg 58.31min North 149deg 51.81min West XCP Drop 4 at CTD Station 11 Sta72_150W SerialNo. 8021008 2008-03-28/0014 UTC 72deg 03.74min North 150deg 05.27min West XCP Drop 5 at CTD Station 18 Sta86_136W SerialNo. 8021016 2008-04-08/1636 UTC 86deg 19.56min North 135deg 59.51min East XCP Drop 6 at CTD Station 21 Sta86_90E SerialNo. 8021013 2008-04-10/2003 UTC 85deg 59.27min North 090deg 40.57min East XCP Drop 7 CTD Station 23 Sta87_135E SerialNo. 8021020 2008-04-11/1758 UTC 87deg 11.36min North 135deg 19.80min East XCP Drop 8 at CTD Station 24 Sta87_90E SerialNo. 8011011 2008-04-12/1241 UTC 86deg 53.22min North 089deg 34.19min East XCP Drop 9 at CTD Station 29 Sta8835_135E SerialNo. 8011045 2008-04-18/1509 UTC 88deg 38.52min North 135deg 25.08min East XCP Drop 10 at CTD Station 30 Sta89_180 SerialNo. 8021019 2008-04-18/1820 UTC 88deg 59.55min North 178deg 49.71min East These measurements were made with a Sippican Expendable Current Profiler following a Twin Otter landing at these positions on the Arctic sea ice, as part of the observational program of the North Pole Environmental Observatory. A brief description of XCPs may be found at http://www.sippican.com/contentmgr/showdetails.php/id/312 . CTD profiles recorded during the same stations are included in the Dataset - North Pole Environmental Observatory Aerial CTD Survey at CADIS ( http://aoncadis.ucar.edu/home.htm ), and are a source of buoyancy data for further XCP analysis. The XCP measures velocity by sensing the voltage generated by the movement of conductive seawater through the earth's magnetic field. The voltage difference is measured between two electrodes on the surface of the XCP, which rotates about once every meter of fall. We use a MATLAB program written by John Dunlap of the UW Applied Physics Lab to process the raw data. This program is available at http://ohm.apl.washington.edu/~dunlap/xcpdsp/ In processing, the components of a harmonic fit to the oscillating potential that are in phase and in quadrature with the oscillating output of a flux gate compass are taken as the magnetic north and magnetic east components of velocity. In order to maximize the potential vertical resolution of the resulting profiles, we chose to do the fits over 2-m, half overlapping "chunks". This gives a vertical wavenumber cutoff of 0.5 cycle m-1 that for the Arctic data is well into the noise floor of the instrument. Users may then filter these basic data in ways appropriate to their applications. Further analysis using these data may be viewed at (http://psc.apl.washington.edu/northpole/Mixing.html). For further information, please contact Dr. James Morison morison@apl.washington.edu (206) 543-1394 Roger Andersen roger@apl.washington.edu (206) 543-1258 at Polar Science Center, Applied Physics Lab, University of Washington 1013 NE 40th, Seattle, WA 98105-6698 USA FAX (206) 616-3142