Nansen and Amundsen Basins Observational System (NABOS) NSF Grant ARC-1203146 Eurasian and Makarov basins observational network targets changes in the Arctic Ocean Expendable Current Profiles from NABOS 2013 Cruise NABOS 2013 Date Latitude Longitude XCP s/n MagDec Filename (E+/W-) XCP Drop 1 2013-9-09 80 32.0 North 111 37.6 East 13021008 17.82 NABOS_2013_XCP01.txt XCP Drop 4 2013-9-09 79 49.2 North 107 40.3 East 13021004 20.49 NABOS_2013_XCP04.txt XCP Drop 7 2013-9-14 82 07.2 North 097 05.1 East 13021012 47.80 NABOS_2013_XCP07.txt XCP Drop 8 2013-9-14 82 18.5 North 097 33.7 East 13021011 48.59 NABOS_2013_XCP08.txt XCP Drop 9 2013-9-16 84 00.8 North 090 03.1 East 13021009 57.48 NABOS_2013_XCP09.txt XCP Drop 10 2013-9-16 83 45.1 North 090 02.1 East 12091012 56.43 NABOS_2013_XCP10.txt XCP Drop 12 2013-9-16 83 15.2 North 090 02.7 East 13021018 54.46 NABOS_2013_XCP12.txt XCP Drop 13 2013-9-16 82 59.9 North 090 06.1 East 13021020 54.16 NABOS_2013_XCP13.txt XCP Drop 14 2013-9-16 82 40.8 North 089 59.3 East 13021021 52.20 NABOS_2013_XCP14.txt XCP Drop 15 2013-9-17 82 18.1 North 090 03.5 East 13021034 50.73 NABOS_2013_XCP15.txt These measurements were made with a Sippican Expendable Current Profiler from the R/V Federof, as part of the observational program of the Nansen and Amundsen Basins Observational System (NABOS) 2013 Cruise by John Guthrie and Mattew Alkire of the Polar Science Center, University of Washington. Of 16 Expendable Current Profilers expended, ten successfully measured profiles. The other six may have been duds, been compromised by interference, or were unable to resolve a measurement due to the very low horizontal geomagnetic field in the high Arctic. A brief description of XCPs may be found at http://www.sippican.com/contentmgr/showdetails.php/id/312 . 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. The NABOS 2013 Cruise also included an extensive series of CTD stations, including stations close enough to the XCP Drops to provide bouyancy information for analysis. These data are available through the NABOS website at: http://research.iarc.uaf.edu/NABOS2/cruise/2013/ CTD stations corresponding to the XCPs are: XCP Drop 1 = NABOS 2013 CTD Station 63 XCP Drop 4 = NABOS 2013 CTD Station 67 XCP Drop 7 = NABOS 2013 CTD Station 90 XCP Drop 8 = NABOS 2013 CTD Station 91 XCP Drop 9 = NABOS 2013 CTD Station 99 XCP Drop 10 = NABOS 2013 CTD Station 100 XCP Drop 12 = NABOS 2013 CTD Station 102 XCP Drop 13 = NABOS 2013 CTD Station 103 XCP Drop 14 = NABOS 2013 CTD Station 104 XCP Drop 15 = NABOS 2013 CTD Station 106 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. Matthew Alkire malkire@apl.washington.edu (206) 897-1623 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