Date: Mon, 22 Jul 1996 15:09:16 +1000
From: Brian Griffiths 

ACE-1 Data Workshop
Report of the Seawater Processes Working Group

	Most of the Discoverer's oceanographic and hydrocarbon data was in the
CODIAC data base prior to the workshop.  None of the Southern Surveyor
oceanographic data was available due to the lack of post-cruise data
processing personnel in Hobart.  This has now been rectified, and the data
is expected to be available by November 1996.  The Discoverer/Southern
Surveyor intercomparison station at 47o 55S, 147 o 25E will be critical in
cross-calibrating the two data sets.
	There was agreement to write a Overview paper which would describe the
surface oceanography for the two major legs (Trans-Pacific and Tasmanian)
covered during the experiment.  Bates and Quinn would take the lead in the
Trans-Pacific leg, with emphasis on water mass and gyre boundaries and
frontal regions encountered along the track that could affect aircraft
measurements.  Griffiths would take the lead in the surface oceanography
around Tasmania, with emphasis on when the ships were in which water masses.
This section would include estimates of the sea-air fluxes of NH3, DMS, and
possibly CO2 and hydrocarbons.  A biology section could include surface
chlorophyll, nutrients, phytoplankton speciation, production, and grazing
rates, all of which may affect DMS production.  The potential authors
include Griffiths, Clementson, Parslow, Tilbrook (CSIRO), Bates, Quinn,
Feely (PMEL), Curran/Jones (JCU), Greene (TAMU), and possibly others.

	One link between ship and aircraft data sets were identified during the
discussion.  North of New Zealand, there was a correlation between DMS
measured on Disco and methyl iodide measured on the C-130.  During 
Lagrangian A and B, concentrations of propene and ethene dropped markedly 
as the aircraft crossed from
warmer, subtropical waters into the cooler subantarctic/polar waters.  This
led to a decision to try and get a water mass specific relationship between
sea surface temperature and chlorophyll-a to look for further correlations
with aircraft-sampled, "biological" data.

	It became clear that satellite sea surface temperature images under the
aircraft tracks would be very useful in identifying the water masses that
the aircraft was flying over.  Brian Griffiths will try and match cloud-free
images from the CSIRO archive to aircraft tracks, and make these available
in the data base as gif images.  He will also oversee the prepartion of the
SST image with both ships cruise tracks, and the aircraft tracks during
Lagrangian A and B on it for use in the ACE-1 data report.

	The DMS flux modelling will proceed using regional averages of DMS in the
water and atmosphere from each ship during the various time periods.  This
will need to be a cooperative effort between Bates and Curran/Jones.  Other
factors that can be factored in to understanding differences in flux rates
will include phytoplankton species abundances, zooplankton grazing rates,
and mixed layer depths, nutrients, and temperatures (Griffiths/Greene)

	There is the potential for comparison of upwelling radiances, continuous
spectral optical depth, and ocean colour  measured by John Porter on the
C-130 with data sets from both Discoverer and Southern Surveyor.  Porter
obtained radiance data on flights 10, 18-21, and 28.  This comparison should
be pursued between Porter, Parslow (CSIRO) and  Quinn.

Brian Griffiths
CSIRO Divison of Fisheries

Brian Griffiths
CSIRO Division of Fisheries, GPO Box 1538, Hobart, Tasmania, Australia 7001
Australian telephone and fax:  (002) 325-338 and (002) 325-000
International telephone and fax:  +61-02-325-338 and +61-02-325-000