RV Franklin Cruise Fr 10/91 (09FA1091)
======================================

Itinerary
=========

Depart Sydney  1500 Friday 15th November, 1991
Arrive Noumea  1130 Tuesday 3rd December, 1991
Depart Noumea  1000 Wednesday 4th December, 1991
Arrive Sydney  0900 Sunday 15th December, 1991


Scientific programs
===================

1. Ocean transport in the Tasman and Coral Seas

2. Application and validation of the along track scanning radiometer
   of ERS-1.


Principal Investigator
======================

Dr John Church, CSIRO Division of Oceanography


Other Investigators
===================

Dr Gary Meyers and Mr Fred Boland, CSIRO Division of Oceanography

Drs Ian Barton and Fred Prata, CSIRO Division of Atmospheric Research


Cruise narrative
================

After sailing from Sydney, we steamed straight to the inshore end of the 
mooring section.  We then steamed over the mooring section to get a better 
idea of what the bathymetry was like (there is very little bathymetry data 
available for this area).  The first (inshore) mooring was deployed before 
breakfast on the 17th of November.  The next two moorings were deployed on 
the same day.  The fourth mooring was not attempted on this day because of 
deteriorating weather - the Doppler profilers could not be moved safely from 
the forward end of the rear deck in the conditions.  The 30S CTD section was 
commenced overnight, and the remaining 3 moorings were deployed on the 18th 
in better conditions.  The mooring work went without incident.

The 30S section was then continued, and was completed on the 26th of 
November.  The new CTD deck unit, rosette unit and display system were being
used for the first time on this cruise.  The most serious problem with the
CTD system was some misfires of the rosette.

The section from New Zealand was commenced on the 27th of November and was
completed without incident (apart from a few misfires) on the 2nd of
December.  Because the port call had been moved back one day and because we 
had made up a substantial amount of time on the New Zealand - Noumea section, 
we did the first few stations of the 23S section before steaming into Noumea.

After leaving Noumea, we continued the 23S section in good, but mostly
cloudy weather.  CTD work continued, but the cloudy weather was not ideal for
the ERS-1 verification work.  The "Flying Fish' was deployed for the first 
time (without electronics) on the 5th of December and again after some 
adjustment to the harness on the 7th of December.

A number of satellite tracked drifters were deployed for George Cresswell
along this section.  In addition, Rick Bailey (who had joined the ship in 
Noumea) performed a number of XBT and XCTD trials and calibrations.

The 23S section was completed on the 9th of December and a number of 
transects across the East Australian Current using the Doppler profiler and 
XBTs were performed.  The repeat of the inshore part of the 30S section was 
commenced on the 12th of December but was abandoned on the 13th of December 
because of deteriorating weather (40 knot north-easterly winds with stronger 
gusts and squalls).  We then steamed towards Sydney, performing another 
ADCP/XBT transect across the EAC into Sugarloaf Point on the way.


CTD Measurements During RV Franklin Cruise Fr10/91
==================================================

The CTD used throughout this RV Franklin cruise Fr10/91 was CSIRO CTD No. 4
(A Neil Brown Instrument Systems MkIII B profiler, Serial Number:  01-1197)
The Sensors on the profiler where :

     Sensor             Manufacturer          Resolution   Accuracy
     ======             ============          ==========   ========
     Temperature:       Rosemount PRT         0.0005C      0.003C
     Conductivity:      EG&G NBIS             0.001mmho    0.005mmho
     Pressure           Paine Instruments     0.1 dbar     6.5 dbar
     Dissolved Oxygen   Beckman Polarographic

The fast response thermistor had been removed prior to this cruise, in fact 
the thermistor had not been used on this instrument in the field.

CTD Temperatures are calibrated against water (0.010C) and phenoxybenzene 
(~27C) using platinum resistance thermometers as transfer standards.  The 
lab which carries out this calibration (The CSIRO Division of Oceanography 
Calibration Facility) is accredited by NATA, Australia's National Association 
of Testing Authorities, to calibrate CTDs to 0.003C at the water triple point 
and 0.004C at the phenoxybenzene point.  Both of these uncertainties are at 
the 99% level.  Calibration is carried out as often as practicable given the 
Franklin's itinerary.  

The CTD was calibrated in August 1991 and the constants from that calibration 
were used for this cruise.  The next calibration, in August 1992, showed no
significant change in the calibration of the CTD.

All CTD temperatures are ITS-90.

The CTD pressure was calibrated against a deadweight tester in the "down cast" 
direction only.  In addition, the pressure at the first "in water" sample 
were used to derive an offset for each station.

Salinity calibration are based on in situ bottle data.  Laboratory checks are 
only maintained to ensure the sensor is operating correctly.  Using 1717
sample bottles out of a total of 1931, the difference between the CTD 
salinities and the water samples showed a standard deviation of 0.0027psu
for the whole water column.

The calibration technique follows that used by Bob Millard's group at WHOI 
closely.  The station groupings used were 1-14, 15-18, 19-25, 26-46, 47-53,
54-69, 70-86, 87-90, 91-94, 95-103 and 104-121.

Dissolved oxygen calibration is carried out using a method very similar to 
that described in Owens and Millard Jr (1985).  This method is to fit the 
downcast profile of dissolved oxygen to the sample bottles collected during 
the upcast.  

The difference between the CTD downcast oxygens and the sample bottle 
oxygens show a standard deviation of 3.57 umol/L (equivalent to 0.080 
mL/L) for the whole water column.  

Problems were experienced with the dissolved oxygen sensors through this 
cruise.  The sensor initially exhibited a lack of sensitivity which
was compensated for by the fitting routines used in the calibration process.
Stations 42 to 52 were fitted singly to account for this accelerated 
sensitivity loss.  The cell was changed following station 52. 
Problems of noisy data generally continued and in particular a step like 
phenomenon appeared in the deep data until the cell was tightened in its
mount prior to station 89.  The general noise levels seemd to remain but the
step like phenomenon disappeared.


CTD Data Collection and Processing
==================================

A PDP 11/73 computer with a 150Mb hard disk was used as the primary data 
logging device.  Data is logged directly to hard disk, whilst simultaneously 
recorded on audio tape.  Logging is commenced before the CTD profiler is 
deployed and downcast is normally logged as a single file.  Positions and 
times are logged automatically.  Complete upcasts are recorded and the 
locations of samples are flagged in the data file.  15 second bursts are used
for the calibration.

Following completion of the station uncalibrated averaged files are sent 
over the network to a VAX 11/750 for use on-board during the cruise and 
the raw data and pre-processed files are written to 9 track tape.  The data 
is later transfered from tape to Exabyte cartridge using the VAX/VMS Backup 
utility.  These cartridges contain all the raw data collected during a cruise 
and are permenantly archived.

Post-cruise processing follows the following scheme: 

- there is an initial 'clean up' stage were station data is checked, unwanted 
  casts are removed, etc.

- a set of uncalibrated 2dB average files are produced, as well as summaries 
  of the data for each sample burst.  At this stage temperature and pressure 
  calibrations are put in.

- bad data (e.g. where something has got stuck in the conductivity cell) is 
  removed.

- the sample data is merged with the hydrology data, and some samples are 
  flagged as being 'unsuitable for calibration (e.g. due to large gradients).
  An iterative process then follows, where outliers are progressively removed 
  and a calibration constant (a conductivity ratio) is determined for each 
  station.

- once this has been done, calibrated 2dB average files are produced.  A 
  simple recursive filter is used to 'slow down' the faster sensors (pressure 
  and conductivity) to the slowest sensor (temperature - the response time 
  of the platinum resistance thermometer is ~.175 seconds).  Values are 
  checked for implausible gradients, and any ascending parts of the trace 
  are ignored (i.e. any values for which the pressure is less than the 
  maximum pressure for this cast so far are ignored).  At the same time 2dB 
  averages of oxygen current and oxygen temperature are calculated.

- the calibrated 2db averages are plotted, and the plots examined.  In 
  addition, T/S curves of groups are plotted and checked for agreement of the 
  deep T/S values.  The traces are also examined for density inversions, and 
  sections removed if this seems appropriate. 


Salinity and Dissolved Oxygen Measurements made during RV Franklin Cruise 
Fr10/91 (09FA1091).
=========================================================================

Salinity.  The water samples salinities where measured with a YeoKal Model 
601MkIII Inductive Salinometer that was standardised daily with IAPSO 
Standard Sea Water (SSW) Batch P112 (Cond Ratio: 0.99984).  
The accuracy of the salinnometer claimed by the manufacturer is 0.003 psu. 
(Yeo-Kal Electronics Pty Ltd, Brookvale, NSW, 2100, Australia)

Oxygen. The method used is a modified Winkler titration.  All oxygen values 
(Bottle and CTD were converted from umol/l to umol/kg using the salinity of 
the sample and the nominal temperature (25C) of the lab in which the 
analyses were done.


Nutrient Analyses
=================

Samples are collected in 15ml polypropylene tubes and frozen for up to 
one week before analysis using a Technicon AA2 system.  They are thawed at 
room temperature.

Nitrate determination is based on the reduction of nitrate in the sample 
to nitrite using a granulated cadmium reductor column and imidazole buffer.  
Nitrite then reacts with sulphanilimide to form a diazonium ion which reacts 
with napthylethylene dihydrochloride to form a coloured azo dye which is 
measured at 550nm.  Nitrite is also determined using the same chemistry 
without the use of a reductor column.

Dissolved phosphate is determined by reaction with acid molybdate in the 
presence of antimony ion.  Phosphomolybdate is then reduced by ascorbic acid 
at 37C and the blue complex measured at 880nm.

Reactive silicate is combined with acid molybdate and the complex reduced 
by methylaminophenol.  Interference by phosphate is eliminated by the addition
of oxalic acid which reacts with excess molybdate and the blue colour is 
measured at 820nm.

Nutrients are converted from umol/l to umol/kg using the nominal 
temperature of the chemistry lab on RV Franklin (25C) 


Miscellaneous
=============

All sounder data for this cruise was collected with the sounder using 
a sound speed of 1498 metres/second.  The depth of the sounder below the
water surface has been taken into account.


Table: Cruise Participants
==========================

        Fr10/91         Sydney - Sydney          15 Nov - 15 Dec 1991


        Name                Responsibility        Affiliation
        -----------------------------------------------------

	Leg 1 - Sydney to Noumea

	Neil White          Chief Scientist        CSIRO DO
        Fred Boland         Moorings/CTD watch     CSIRO DO
        Kevin Miller        Moorings/CTD watch     CSIRO DO
        Danny McLaughlin    Moorings/CTD watch     CSIRO DO
        Ron Plaschke        Nutrients/Salts/DO's   CSIRO DO
        Bob Griffiths       Nutrients/Salts/DO's   CSIRO DO
	Phil Adams          Electronics            CSIRO DO
        Bernadette Heaney   CTD watch              CSIRO DO
        Phaedra Hay         CTD watch              Sydney University
        Bob Cechet          ERS-1 validation       CSIRO DAR

	Leg 2 - Noumea to Sydney

	Neil White          Chief Scientist        CSIRO DO	
        John Church         CTD watch              CSIRO DO
        Kevin Miller        CTD watch              CSIRO DO
        Rick Bailey         XCTD trials            CSIRO DO
        Ron Plaschke        Nutrients/Salts/DO's   CSIRO DO
        Bob Griffiths       Nutrients/Salts/DO's   CSIRO DO
	Phil Adams          Electronics            CSIRO DO
        Bernadette Heaney   CTD watch              CSIRO DO
        Daniel Large        CTD watch              Sydney University
        Bob Cechet          ERS-1 validation       CSIRO DAR
        John Bennet         ERS-1 validation       CSIRO DAR


References
==========

Owens, W. Brechner and Robert C. Millard Jr. " A new Algorithm for CTD 
Oxygen Calibration." Journal Of Physical Oceanography, 15, 621-631. 1985




