Research Programme, 1989a). Its purpose and
achievement was to present the Implementation
Plan to national authorities, to gain their interest,
and to gauge their commitment. Thirty-one
countries announced their intention to commit
resources. By the end of the field phase, we could
count the actual involvement of 22 countries, the
contributions from which varied from more than
50% by the USA to small but valuable local contributions by small countries.
In this review we have chosen to pick out some
highlights in the planning process that at the time
were seen to be important, or in retrospect have
become so.
The first three meetings of the SSG through
early 1985 were critical in firmly establishing the
objectives of the experiment and concluding that
these could not be achieved by a generalized
expansion of large-scale oceanography. This view
was encapsulated eventually in the now muchrepeated statement of the two goals of WOCE:
¥ To develop models useful for predicting climate
change and to collect the data necessary to test
them; and
¥ To determine the representativeness of the
specific WOCE data sets for the long-term
behaviour of the ocean, and to find methods for
determining long-term changes in the ocean
circulation.
This emphasis was not particularly limiting on the
scope of the field programmes that would emerge.
Indeed the initial WOCE working groups on surface forcing, reference level velocity, critical aspects
of temperature/salinity distribution, tracer distributions and inputs, variations in diapcynal mixing,
and depth of winter mixing read like a catalogue
of problems in physical oceanography at the time.
A careful reading of the WGs’ terms of reference
(SSG-1) is necessary to understand the focus provided by the WOCE goals. The working groups’
reports contributed to a further refinement of goal
1 of WOCE to become:
To determine and understand:
the large-scale fluxes of heat and fresh water
and their divergences;
the dynamic balance of the circulation and its
response to changing surface fluxes;
components of variability on months to years
and megametres to global scale; and
volume and location of water masses with
ventilation times of 10–100 years.
The working groups were all, in one way or
another, asked to pay close attention to the ability
of existing measurement systems to meet the defined
accuracy requirements. If such requirements could
not be met, they were asked to consider if they
could realistically be met by developing technology
during the period of WOCE. The absolute priority
for the success of the experiment was, to have at
least one dedicated altimetric satellite mission,
coincident with a global hydrographic survey of
higher accuracy than ever before, of sufficient alongtrack resolution to avoid aliasing of the eddy field.
The TOPEX/POSEIDON satellite, while ultimately highly successful, provided anxious moments
up to the time of launch when the durability of
some of its batteries came into question. The SSG
encouraged the launch of a geodetic satellite that
would provide a greatly enhanced reference geoid
to allow inference of the absolute topography of
the sea surface. Coincidence in time was not a
requirement, but the SSG foresaw the possibility of
‘data decay’ if the geoid and altimetry observations were too far separated in time. That satellite
has yet to be launched. On the other hand, technical developments, some driven directly by the
requirements of the programme, added greatly to
the success of the experiment. The in-situ development with potentially the greatest direct impact on
a global scale was the Autonomous Lagrangian
Circulation Explorer (ALACE) programme of
floats to measure the deep reference velocities and
described elsewhere in this book (Davis and Zenk,
Chapter 3.2). While RAFOS (reversed SOFAR)
was building on the established SOFAR acoustic
navigation technology for floats and would contribute greatly to the dynamical studies in the
North and South Atlantic, ALACE was a developing technique. For ship-based velocity measurements, Global Positioning System (GPS) navigation
and differential techniques permitted the hoped
for, but in 1985 uncertain, development of Acoustic
Doppler Current Profilers (ADCPs) as a valuable underway and on-station tool for the measurement of deep velocity profiles (King et al.,
Chapter 3.1).
The Numerical Experimentation Group (NEG),
befitting the central role of models in the project’s
goals, became the first of WOCE’s ‘permanent’
1.3 The Origins, Development and Conduct of WOCE
37
Thompson, Crease and Gould
achievement was to present the Implementation
Plan to national authorities, to gain their interest,
and to gauge their commitment. Thirty-one
countries announced their intention to commit
resources. By the end of the field phase, we could
count the actual involvement of 22 countries, the
contributions from which varied from more than
50% by the USA to small but valuable local contributions by small countries.
In this review we have chosen to pick out some
highlights in the planning process that at the time
were seen to be important, or in retrospect have
become so.
The first three meetings of the SSG through
early 1985 were critical in firmly establishing the
objectives of the experiment and concluding that
these could not be achieved by a generalized
expansion of large-scale oceanography. This view
was encapsulated eventually in the now muchrepeated statement of the two goals of WOCE:
¥ To develop models useful for predicting climate
change and to collect the data necessary to test
them; and
¥ To determine the representativeness of the
specific WOCE data sets for the long-term
behaviour of the ocean, and to find methods for
determining long-term changes in the ocean
circulation.
This emphasis was not particularly limiting on the
scope of the field programmes that would emerge.
Indeed the initial WOCE working groups on surface forcing, reference level velocity, critical aspects
of temperature/salinity distribution, tracer distributions and inputs, variations in diapcynal mixing,
and depth of winter mixing read like a catalogue
of problems in physical oceanography at the time.
A careful reading of the WGs’ terms of reference
(SSG-1) is necessary to understand the focus provided by the WOCE goals. The working groups’
reports contributed to a further refinement of goal
1 of WOCE to become:
To determine and understand:
the large-scale fluxes of heat and fresh water
and their divergences;
the dynamic balance of the circulation and its
response to changing surface fluxes;
components of variability on months to years
and megametres to global scale; and
volume and location of water masses with
ventilation times of 10–100 years.
The working groups were all, in one way or
another, asked to pay close attention to the ability
of existing measurement systems to meet the defined
accuracy requirements. If such requirements could
not be met, they were asked to consider if they
could realistically be met by developing technology
during the period of WOCE. The absolute priority
for the success of the experiment was, to have at
least one dedicated altimetric satellite mission,
coincident with a global hydrographic survey of
higher accuracy than ever before, of sufficient alongtrack resolution to avoid aliasing of the eddy field.
The TOPEX/POSEIDON satellite, while ultimately highly successful, provided anxious moments
up to the time of launch when the durability of
some of its batteries came into question. The SSG
encouraged the launch of a geodetic satellite that
would provide a greatly enhanced reference geoid
to allow inference of the absolute topography of
the sea surface. Coincidence in time was not a
requirement, but the SSG foresaw the possibility of
‘data decay’ if the geoid and altimetry observations were too far separated in time. That satellite
has yet to be launched. On the other hand, technical developments, some driven directly by the
requirements of the programme, added greatly to
the success of the experiment. The in-situ development with potentially the greatest direct impact on
a global scale was the Autonomous Lagrangian
Circulation Explorer (ALACE) programme of
floats to measure the deep reference velocities and
described elsewhere in this book (Davis and Zenk,
Chapter 3.2). While RAFOS (reversed SOFAR)
was building on the established SOFAR acoustic
navigation technology for floats and would contribute greatly to the dynamical studies in the
North and South Atlantic, ALACE was a developing technique. For ship-based velocity measurements, Global Positioning System (GPS) navigation
and differential techniques permitted the hoped
for, but in 1985 uncertain, development of Acoustic
Doppler Current Profilers (ADCPs) as a valuable underway and on-station tool for the measurement of deep velocity profiles (King et al.,
Chapter 3.1).
The Numerical Experimentation Group (NEG),
befitting the central role of models in the project’s
goals, became the first of WOCE’s ‘permanent’
1.3 The Origins, Development and Conduct of WOCE
37
Thompson, Crease and Gould