RAFOS Floats in the North Atlantic; University of Rhode IslandEntry ID: URI_RAFOS_Floats
Abstract: RAFOS floats are neutrally buoyant isopycnal drifters, which are tracked
acoustically by ranging to as many as five sound sources that were moored at
the depth of the permanent sound channel south of the Gulf Stream along a line
between 73W and 51W. All sources transmit a precisely timed frequency
modulated, continuous wave (CW) signal every eight hours. The floats, ... which
are equipped with accurate timing, determine the times of arrival of the
signals. These are saved in the float's microprocessor memory along with
measurements of pressure and temperature. At the end of its mission, each
float releases ballast, returns to the surface and starts its radio telemetry.
The telemetered data are received by Systeme ARGOS, a French satellite--based
data collection and platform location system. Once the data have been
assembled in a computer, the trajectory of the float can be reconstructed from
the time series of acoustic travel times. Each RAFOS float data set contains
a time series of concurrent trajectory, temperature and pressure measurements.
The RAFOS system has been described in detail by Rossby et al. (1986). The
data processing has been discussed in a data report by Bower et al. (1986).
Floats were launched in the axis of the current, identified as the point at
which the 15 deg C isotherm crosses 450m. The actual launch site is
determined by a series of XBT's taken until the 15 deg C isotherm intersects
450m. The launch procedure is described in detail by Bower et al. (1986).
(Click for Interactive Map)
Start Date: 1984-01-17Stop Date: 1990-03-26
OCEANS > OCEAN ACOUSTICS > ACOUSTIC FREQUENCY
OCEANS > OCEAN ACOUSTICS > ACOUSTIC VELOCITY
OCEANS > OCEAN CIRCULATION > GYRES
OCEANS > OCEAN CIRCULATION > OCEAN CURRENTS
OCEANS > OCEAN CIRCULATION > THERMOHALINE CIRCULATION
OCEANS > OCEAN CIRCULATION > WATER MASSES
OCEANS > OCEAN PRESSURE > WATER PRESSURE
OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE
ISO Topic Category
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Email: sfontana at gso.uri.edu
227 Watkins URI/GSO
Province or State: RI
Postal Code: 02882
Email: trossby at gso.uri.edu
Graduate School of Oceanography Narragansett Marine Laboratory University of Rhode Island
Anderson-Fontana,S. and H.T. Rossby, 1991. RAFOS floats in the SYNOP
Experiment 1988-1990. G.S.O. Univ. of Rhode Island Tech. Report 91-7, 155 pp.
Hummon, J., T. Rossby, E. Carter, J. Lillibridge III, M. Liu, K. Schultz-Tokos,
S. Anderson-Fontana, A. Mariano, 1991. The Anatomy of Gulf Stream Meanders.
G.S.O. Univ. of Rhode Island Tech. Report 91-4, vol. I and II.
Bower, A., R. O'Gara and T. Rossby, 1986. RAFOS float pilot studies in the
Gulf Stream 1984-1985. G.S.O. Univ. of Rhode Island Tech. Report 86-7, 110 pp.
Rossby, T., D. Dorson and J. Fontaine, 1986. The RAFOS system. J. Atmos. and
Oceanic Tech., 3, 672-679.
Creation and Review Dates
Last DIF Revision Date: 2008-07-03