North Pole Environmental Observatory 2004 Aerial CTD Survey NSF Grant OPP-9910305 CTD Station/Location Position Latitude _ Longitude Cast Date _ Time Cast 1 Mooring Camp 89 deg 27.83 min North _ 61 deg 59.91 min East 4/23/2004 _ 2011 UTC Cast 5 Borneo 3 89 deg 18.84 min North _ 125 deg 37.58 min East 4/26/2004 _ 1407 UTC Cast 6 Borneo 4 89 deg 18.98 min North _ 125 deg 26.27 min East 4/26/2004 _ 1539 UTC Cast 7 85N-170W 85 deg 00.72 min North _ 166 deg 36.86 min West 4/27/2004 _ 0422 UTC Cast 8 86N-170W 86 deg 08.72 min North _ 171 deg 17.43 min West 4/27/2004 _ 0832 UTC Cast 9 87N-180 87 deg 16.28 min North _ 178 deg 53.06 min West 4/27/2004 _ 1158 UTC Cast 10 89N-90W 89 deg 04.11 min North _ 87 deg 19.05 min West 4/28/2004 _ 0559 UTC Cast 11 90N North Pole 89 deg 57.70 min North _ 110 deg 33.15 min East 4/28/2004 _ 0913 UTC Cast 12 8840N-180 88 deg 41.33 min North _ 179 deg 45.65 min West 4/28/2004 _ 1233 UTC Cast 13 88N-180 87 deg 59.92 min North _ 179 deg 50.81 min East 4/29/2004 _ 0932 UTC Cast 14 87N-90W 86 deg 59.68 min North _ 90 deg 29.65 min West 4/29/2004 _ 1331 UTC Each cast is an ASCII file of seven numerical columns with a short header- _ Depth (m) _ Pressure (dbar) _ Temperature in situ (deg C) _ Potential Temperature in situ (deg C) _ Conductivity (S/m) _ Salinity (psu) _ Density (sigma-theta) These measurements were made with a Seabird SBE-19 Seacat following a landing at these positions on the Arctic sea ice, as part of the observational program of the North Pole Environmental Observatory. Instrument problems troubled the first few casts, taken with a lightweight winch directly through an auger hole in the ice at the NPEO mooring recovery and redeployment camp and the Russian temporary camp Borneo. A leaky oxygen sensor connector drew down instrument power and compromised test Casts 2, 3, and 4 sufficiently that they are not reported here. Once the leak was found and fixed, quite satisfactory Casts 5 and 6 were obtained at Borneo. The best Mooring Camp profile was the uptrace from Cast 1, which showed down and up cast agreement above 100m depth and at greater depths reasonably matched Cast 11 (St90n) at the North Pole which was not too far away. Casts 6 through 14 were taken from a Twin Otter and included water sampling with Niskin Bottles for chemistry. These typically revisited a Station sampled during earlier NPEO deployment years. Cast 11 was very near the North Pole. Extreme measures were taken to protect the Seabird SBE-43 Oxygen sensor from exposure to very cold air temperatures, and its performance at these remote stations was excellent. However, the proper processing algorithm for SBE-43 data taken in very cold temperatures is a current source of some controversy, and we are working with the manufacturer on this issue. Until this procedure is optimum, we would ask users interested in dissolved oxygen profiles to contact us directly. Cast 6 at Borneo had a cold instrument for the top of the downcast which was not readily replaced by the top of the upcast, and it was felt best to allow it to start down from 17 meters. Cast 8 (86N-170W) shows a conductivity hiccup going down to 100m, possibly due to biology. Fortunately the uptrace was a nice match, and replaced the downcast above 100m. Processing followed the recently-modified (June 2003) SEASOFT recipe to minimize salinity spiking with certain constants determined by empirical trial. Conductivity and temperature were low pass filtered with a time constant of 0.5 seconds, and temperature was advanced relative to pressure by 0.7 seconds. Except where noted above, the reported profile is the down trace which minimizes instrument wake effects. Profile plots and other analysis using these data may be viewed at the NPEO website (http://psc.apl.washington.edu/northpole/CTDSurvey2004.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