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WOCE
The
origins of Argo can be
found in the 1990-1997
World Ocean Circulation Experiment (WOCE).
WOCE is part of the World
Climate Research Programme (WCRP) and
set out to collect an unprecedented set of observations.
WOCE needed to collect data on ocean currents at
about 1000m throughout the oceans. To do this
Russ Davis from Scripps
Institution of Oceanography in California and Doug Webb of Webb
Research Corporation developed the Autonomous Lagrangian Circulation
Explorer (ALACE).
(Davis, 1991, Davis et al. 1992). ALACE floats used
the principle of neutral buoyancy invented
by John Swallow in the mid
1950s to follow the currents at a particular pressure level.
(Swallow, 1955). (Information on the history of the development and
use of neutrally buoyant
floats can be found at
Southampton
Oceanography Centre and at the
University of Rhode Island)
Each ALACE float rose to the sea surface at
regular intervals to allow its position to be
fixed by satellite.
About 1000 ALACE-type floats were deployed by WOCE. (The data from
these
floats is available online)
It was soon realised that as they rose to the
surface the ALACEs could also measure the
temperature and salinity of
the water through which they rose and towards the end of WOCE most
of
the ALACEs carried temperature/salinity sensors. They became
Profiling ALACE (PALACE)
floats. (Davis et al 2001).
Potential for Profiling Floats
Two documents
prepared simultaneously in 1998 by Dean Roemmich of Scripps Institution of
Oceanography and Ray Schmitt of Woods Hole Oceanographic Institution explore the potential of
using profiling floats to monitor the ocean.
- "
A Proposal for Global Ocean
Observations for Climate: the Array for Real-time Geostrophic
Oceanography (ARGO)" (Roemmich)
- "
A program for
Global Ocean SAlinity MonitORing (GOSAMOR)" (Schmitt)
Early in 1998, the International Steering Team for
GODAE endorsed the broad concept of a
global array of profiling floats and undertook to
develop a plan. CLIVAR also considered
these two
proposals and gave them high priority in its implementation plan.
A scientific team came together under the
chairmanship of Dean Roemmich and prepared two documents
on Argo:
Thus the Argo project was born.
References
• Davis, R.E. 1991: Observing the general
circulation with floats. Deep-Sea Research, 38(Suppl. 1), 531-571.
• Davis, R.E., D.C. Webb,
L.A. Regier and J. Dufour, 1992: The Autonomous Lagrangian
Circulation Explorer
(ALACE). J. Atmos. Ocean.
Tech., 9, 264-285.
• Davis, R.E., J.T. Sherman and J.
Dufour, 2001: Profiling ALACEs and other advances in autonomous
subsurface
floats. J. Atmos. Ocean.
Tech., Boston, MA. 18, 982-993.
• Swallow, J.C., 1955: A
neutral-buoyancy float for measuring deep currents. Deep-Sea
Research, 3, 74-81.)
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