RV Franklin Cruise Fr 3/94 (09FA0394)
======================================

Itinerary
=========

Depart Hobart       1015 Saturday 10th March, 1994
Arrive Newcastle    0700 Sunday 3rd April, 1994


Scientific program
==================

1. Ocean transport in the Tasman and Coral Seas


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

Dr John Church, CSIRO Division of Oceanography


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

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

Professor Matt Tomczak, Flinders University of South Australia


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

A disappointingly small proportion of the planned CTD work was completed due to
the large (record) amount of time lost due to bad weather and to the longer
than expected amount of time spent recovering the moorings.  Both main CTD
sections have substantial gaps.

However, nearly all of the mooring equipment was recovered.  It will not be
possible to summarise the results from the current meters until this data has
been processed.

We sailed from Hobart at 1015 on Thursday the 10th of March after delays due to
problems with the bow thruster.  The weather was quite good until about 8am the
next morning, at which point we hove to.  By the end of the 4th day at sea we
had been hove to for over three days.  This is, apparently, the longest the
Franklin has ever been hove to in one spell.  Having achieved this unenviable
record (one which we all hope will stand without serious challenge for many
years) we continued CTD work along this section for a few days before having to
heave to again because of strong winds and a big, steep swell from the South.
After two days we were able to do one CTD in marginal conditions before
conditions worsened again.  It was eventually decided to abandon the 43S CTD
section as there was little prospect of it being completed in a reasonable
time.

We then steamed to Cape Reinga and started the section north from there.  This
section was completed without incident and we started the 30S section in good
conditions.  We decided to leave the section on the 25th of March and steam in
to the moorings (near the NSW coast at 30S) and recover the moorings, starting
early on the 28th.  While steaming in a few CTDs were done when weather
permitted - the weather had deteriorated again.

The first mooring was recovered without incident on the morning of the 28th.
The acoustic release on the second mooring didn't respond, so we went on to the
next (in 700m of water) and recovered that without incident.  The three inshore
moorings were recovered on the 29th, leaving only the mooring which hadn't
responded on the 28th.  This mooring was in 4,400 metres of water.  After
trying to communicate with it again at first light on the 30th a release
command was sent and that also had no effect.  After several hours searching
the top instruments were located (in the correct position) with the ships
sounder.  As the acoustic release would not release the only option left was to
trawl for it.  The daylight hours of the 31st of March and the 1st of April
were spent trawling with the top part of the mooring being recovered on the
afternoon of the 1st.  Unfortunately the pressure case (rated to 2000m) of the
ADCP at the top of the mooring had imploded - we think that this had happened
some time before.   Another unsuccessful attempt was made to release the
mooring on the morning of the 2nd before steaming to Newcastle.


CTD Measurements During RV Franklin Cruise Fr3/94
==================================================

The CTD used throughout this RV Franklin cruise Fr3/94 was CSIRO CTD No. 2
(A Neil Brown Instrument Systems MkIII B profiler, Serial Number:  01-1013).
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 immediately before this cruise in February 1994.  
The constants from this calibrations were used.

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 631
sample bottles out of a total of 788, the difference between the CTD 
salinities and the water samples showed a standard deviation of 0.0028psu
for the whole water column.

The calibration technique follows that used by Bob Millard's group at WHOI 
closely.  The stations groups used were 1-3, 4-8, 9-12, 13-16, 17-19, 20-22, 
24-43 and 44-49.

There were a number of problems with CTD oxygen sensors on this cruise 
and the production of oxygen profile data was not attempted.


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

Three Sun Sparcstations are now used for all logging and analysis tasks on RV 
Franklin.  One is dedicated to data logging, another to user analysis and the
third is a spare.  The data that is logged (raw CTD data including flags 
at bottle firings) is very similar to that which was logged on the old system
and the user interface is similar.

All new data files are copied to the other machines on the network within an 
hour and daily backups are made to exabyte on two of the three machines.

Uncalibrated 2 decibar averages are provided for user analysis.

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 
Fr3/94 (09FA0394).
=========================================================================

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 P122 (Cond Ratio: 0.99991).  
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) 



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

        Fr3/94         Hobart - Newcastle       10 Mar - 3 Apr 1994


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

	Neil White        Chief scientist         CSIRO DO 
	Helen Phillips	  CTD watch               CSIRO DO 
	Fred Boland       Moorings/CTD watch      CSIRO DO 
	Kevin Miller      Moorings/CTD watch      CSIRO DO 
	Danny Mclaughlin  Moorings/CTD watch      CSIRO DO 
	Val Latham        Nutrients/Salts/DOs     CSIRO DO
	Les Drury         Nutrients/Salts/DOs     CSIRO DO
	Phil Adams        Electronics             CSIRO DO


References
==========

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




