North Pole Environmental Observatory
NSF Grant OPP-9910305
2002 Aerial CTD Survey

  CTD Cast    Station Name     CTD Location                Cast Date & Time

  Cast 1      Helo.0           88deg 32.4'N _  53deg 00.0'E    4/23/2002 _ 1014 UTC
  Cast 2      Helo.1           88deg 20.7'N _ 113deg 03.0'E    4/23/2002 _ 1334 UTC
  Cast 3      Helo.2           88deg 19.4'N _ 123deg 21.0'E    4/23/2002 _ 1432 UTC
  Cast 4      Helo.3           88deg 18.5'N _ 131deg 59.0'E    4/23/2002 _ 1530 UTC
  Cast 5      Helo.4           88deg 16.3'N _ 140deg 51.7'E    4/23/2002 _ 1626 UTC
  Cast 6      Helo.5           87deg 55.3'N _ 153deg 50.9'E    4/26/2002 _ 1204 UTC
  Cast 7      Helo.6           88deg 06.2'N _ 148deg 05.5'E    4/26/2002 _ 1259 UTC
  Cast 8      Helo.7           88deg 21.1'N _ 118deg 23.7'E    4/26/2002 _ 1406 UTC
  Cast 9      Helo.8           88deg 30.1'N _  71deg 14.1'E    4/28/2002 _ 1041 UTC
  Cast 10     Hydro.0          85deg 10.7'N _ 165deg 16.4'E    4/27/2002 _ 1433 UTC
  Cast 11     Hydro.1          86deg 37.1'N _ 164deg 59.5'E    4/27/2002 _ 1850 UTC



Each cast is an ASCII file of five columns with a short header-
  _ Depth (m)
  _ Pressure (dbar)
  _ Temperature (degC)
  _ Conductivity (S/m)
  _ Salinity (psu)
  
These measurements were made with a Seabird SBE-19 Seacat following a landing 
at these positions on the Arctic sea ice by either a helicopter or skiplane, 
part of the observational program of the North Pole Environmental Observatory.
Casts named 'Helo' were taken from a helicopter to acquire a fine scale 
transect across the Lomonosov Ridge.  Casts named 'Hydro' were taken from a 
Twin Otter and included water sampling with Niskin Bottles for chemistry.

Processing followed the SEASOFT recipe to minimize salinity spiking and 
correct for a thermal lag of the conductivity cell, with certain constants 
determined by empirical trial.  Conductivity was low pass filtered with a time 
constant of 0.3 seconds, pressure filtered with a time constant of 2.0 seconds,
and temperature was advanced relative to pressure by 0.7 seconds.  SEASOFT's 
thermal lag correction was applied with alpha=0.03 and tau=9.0.

Following the processing recipe, these profiles are generally the corrected 
downcasts.  Because of the difficulty of conducting a cast in severely cold 
air temperature, however, the top of some downcasts was compromised by the 
cast starting down at too cold an instrument temperature despite a substantial 
soak time.  In certain of these cases, the top of the upcast was grafted on 
the top of the downcast.

Profile plots and other analysis using these data may be viewed at the NPEO 
website
   (http://psc.apl.washington.edu/northpole/CTDSurvey2002.html).

    For further information, please contact
Dr. James Morison     morison@apl.washington.edu     (206) 543-1394
Dr. Michael Steele    mas@apl.washington.edu         (206) 543-6586
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
