CalCOFI 9810SP CTD Date Processing Notes

Number of station-casts: 19 El Nino CalCOFI Station on Line 90 & 80

Summary: 1998 was an El Nino year so CalCOFI sent the team to collect hydrographic 
data each month. In addition to the full quarterly cruises, abbreviated cruises 
sampled Lines 90 & 80. The RV Robert Gordan Sproul was commissioned for these 
short cruises. 
CalCOFI 9810SP was the first El Nino cruise after the an early 'Fall' CalCOFI 9809NH.
The CTD was deployed off the fantail using the rear A-frame.
Not ideal since the ship's prop wash can mix the surface layer but there was no
sideboard A or J frame. A davit was installed on the port rail to deploy the nets.
On this Oct 1998 cruise, 19 stations of the scheduled 20 stations were occupied.
The Sproul is not a very good open ocean vessel because the rear deck is only a
~1.5m above the water. Sampling was done on the fantail under the A-Frame.

These data are dedicated to the intrepid, dedicated technicians who sail every
month, in sometimes VERY rough conditions, on the Sproul, a round-hulled river/bay
boat. 1998 was a very busy year and it tested everyone's sea-legs & dedication.

The basic Seabird 911 CTD with 20 bottles was deployed to 515m, depth-permitting,
following the usual CalCOFI protocols. Lowering to 10m for 2mins then returning to
surface before starting data acquisition. Then lowering at 20-30m/min for the first
100m then 40-50m/min to terminal depth. This winch setup could rarely reach 60m/min
and with the ship pitching a lot. The CTD was lowered at a speed that would keep
adequate tension on the conductive wire. 
This is the first cruise to deploy a second conductivity sensor. The primary set of 
sensors: temp, cond, & O2 worked well this cruise with no replacements. The secondary
set of T & C sensors also worked fine. All sensors were serviced in Aug 1998, before 
CalCOFI 9809NH.
The O2 sensor worked well near-surface even with prop wash. Near-surface O2 sensor data 
agree very well with bottle samples. The 0.999 Rsquare in the bottle O2 vs sensor O2 data supports 
this statistically. Please remember there are fewer bottle samples to compare to sensor data
this cruise.
No nutrients samples were taken on these ancillary CalCOFI Sproul cruises due to lack of lab
space & nutrient personnel.
 
Software: Starting this cruise, the Seabird SBE Data Processing modules are able to use the
.con files from the cruise. So running the DOS Datcnv(Seasoft exe) in a Windows XP virtual machine 
on Windows 7 was not necessary. All processing was done using SBE Data Processing v7.23.2.

Corrections:
Cast 019 line.station number was corrected in the .hdr file from 83.40.642 to 83.3 40.6.

Other issues: 
Some non-binavg .cnv files had -99 data at the surface that is eliminated by using the
exclude bad data checkbox.

CalCOFI casts numbers (ie filenames) were changed from 01-20 to 001-020; 981001.* >>> 9810001.*... 


JRW 06/01/2022


