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CalCOFI 1004MF
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Written by admininstrator
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Tuesday, 18 May 2010 14:58 |
CalCOFI 1004MF CTD Notes
Deploying CalCOFI's 24 bottle standard rosette was not possible on NOAA RV Miller Freeman due to winch weight restrictions. RV Miller Freeman deploys a 12-10L General Oceanics bottle rosette equipped with a Seabird 911+ CTD & carousel. SIO-CalCOFI installed their 911+ CTD with ancillary sensors on the Miller Freeman's rosette. The CTD was installed and plumb vertically (the typical 24-bottle rosette installation is horizontal). A SBE14 Remote Depth Readout was installed in the winch operator's shack.
Sensors deployed on CalCOFI 1004MF
- 2 - SBE3plus temperature sensors
- 2 - SBE4 conductivity sensors
- 2 - SBE43 oxygen sensors
- 2 - SBE5T pumps
- vertically plumbed
Sensors attached to rosette frame, passive flow:
- Seapoint Chlorophyll Fluorometer
- Wetlabs C-Star 25cm 660nm transmissometer
- Satlantic MBARI-ISUS Nitrate Sensor, powered by 12v Battery
- Biospherical QSP-2300L PAR
- Datasonics/Bethos Altimeter
- SBE18 pH Sensor
Seven of the General Oceanics sampling bottles were adapted with Viton o-rings and coated springs for the primary productivity 14C incubation experiments. In addition to standard 12-bottle 500m (bottom depth permitting) CTD-rosette casts, a second 6-bottle primary productivity cast was performed daily before local apparent noon, calculated using lat/lon. Standard CTD-rosette casts were numbered using order occupied; primary productivity casts were numbered using order occupied + 500 (for example, standard cast 125, prodo cast 625).
Cast types 1, 2, 3, & 4 bottle depths were reduced from 20 to 12.
- Type 1 depths: 0, 10, 20, 30, 50, 75, 100, 150, 200, 300, 400, 500; criteria - chl max 0-40m
- Type 2 depths: 0, 15, 30, 45, 60, 75, 100, 150, 200, 300, 400, 500; criteria - chl max 40-80m
- Type 3 depths: 0, 20, 45, 65, 80, 90, 100, 150, 200, 300, 400, 500; criteria - chl max 80-120m
- Type 4 depths: 0, 30, 60, 80, 100, 115, 130, 150, 200, 300, 400, 500; criteria - chl max >120m
- Bottle depths for each prodo cast are calculated dynamically from secchi depth, the chl max depth, and percent light levels.
To integrate the data collected on CalCOFI 1004MF with the DEPM (Daily Egg Production Method) Survey's 122 stations (legs 1 & 2), order occupied numbering for leg 3 started-continued at 123.
SBE11 deck unit offsets both conductivity sensor by 0.073secs as recommended by Seabird. Voltages 5 & 6 were advanced 4 seconds by the deck unit. These settings were pre-programmed to auto-advance the SBE43 oxygen sensors on CalCOFI 1001NM. Unfortunately, the SBE43's were on voltage channels 4 & 5 this cruise. Processed data files have the appropriate AlignCTD corrections applied: voltage 4 = +4secs; voltage 5 = no offset; voltage 6 (pH) = -4secs.
Cast notes:
- Cast 134 signal was lost at terminal depth, 515m, re-termination was required. This took a few hours so the upcast and bottle samples were not done. There is downcast data but no upcast, bottle samples or mrk file.
- Cast 634 prodo cast was re-done; prior to re-termination, bottle marking-tripping was acting up; it was suspected that bottle #7 close when #2 was triggered without confirmation. Seven bottles were close upon retrieval. 634 (aka 634d) mrk file shows 6 trips but Rossum indicates not bottle confirmation at 18m, bottle #5. Previous cast 634c ros 18m temperature value was pasted into cast 634d.ros - temperatures were comparable to 0.01. Sea cable was re-terminated by MF ET after this cast.
- ISUS battery charging cable shorted out so there were several casts with dropouts or complete failure to log ISUS data. Tabulation will be entered here.
- Stations 144 & 145 were nets only (!) since weather conditions were too rough for CTD deployment. An attempt to launch the CTD resulted in a bottle being broken. Since we were unable to acquire CTD-rosette data & samples, we transited toward shore until conditions would allow all station activities, nets & CTD-rosette.
- No CTD-rosette cast type 4s were done; no station's chl max was ever deeper than 120m.
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Last Updated on Wednesday, 19 May 2010 16:31 |
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