============================== Originally posted 2014-10-23 =================================== North Pole Environmental Observatory 2014 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 NPEO 2014 XCP Profiles NPEO 2014 Date Latitude Longitude XCP s/n MagDec Filename (E+/W-) XCP Drop 1 2014-4-16 87 01.0 North 090 35.0 East 13101012 69.78 NPEO_2014_XCP1_87N90E.txt XCP Drop 3 2014-4-17 85 00.3 North 090 11.4 East 13101003 61.36 NPEO_2014_XCP3_85N90E.txt XCP Drop 4 2014-4-17 85 56.6 North 089 33.9 East 13121002 64.78 NPEO_2014_XCP4_86N90E.txt XCP Drop 5 2014-4-18 89 59.1 North 001 29.6 West 13101005 -10.49 NPEO_2014_XCP5_90N.txt XCP Drop 6 2014-4-19 88 21.1 North 013 01.6 East 13101006 5.28 NPEO_2014_XCP6_Barneo2.txt XCP Drop 7 2014-4-19 88 15.4 North 013 18.3 East 13121000 5.57 NPEO_2014_XCP7_Barneo3.txt XCP Drop 8 2014-4-20 88 09.4 North 014 17.1 East 13121006 6.51 NPEO_2014_XCP8_Barneo4.txt XCP Drop 9 2014-4-20 88 08.1 North 014 17.4 East 13121003 6.52 NPEO_2014_XCP9_Barneo5.txt These measurements were made with a Sippican Expendable Current Profiler through a hole in the Arctic sea ice, as part of the observational program of the 2014 North Pole Environmental Observatory deployment and survey. A brief description of XCPs may be found at http://www.sippican.com/contentmgr/showdetails.php/id/312 . XCP files wwith a suffix like _87N90E were recorded at an NPEO Aerial CTD station of that name following a Twin Otter skiplane landing at that position. XCP files with a suffix like _Barneo1 form a time series at the 2014 Ice Station Barneo. XCP Drop 2 failed to record. CTD profiles 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. Other projects that collected Arctic XCP data and analysis related to 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