ACM4 (Benguela Source and Transport)

Benguela Source and Transport (BEST - ACM4)

This experiment produced 12 current meter records from 4 moorings. You can view metadata and download the records by clicking on links in the table below. A brief description of the experiment also is available. Each current meter record is identified in the table by its depth and the name of the mooring. You may want to look at a map of the array first to see where the moorings were. If you download any of the current meter records you should review the note on file format. From here you can also move up one level to the list of WOCE experiments.

mooring	instr depth	instr type	dates	metadata	download


BEST 1	215 meters	Aanderaa RCM-8	18 Jun 92 - 26 Oct 93	view metadata	download record
BEST 1	520 meters	Aanderaa RCM-8	18 Jun 92 - 23 Oct 93	view metadata	download record


BEST 2	210 meters	Aanderaa RCM-8	19 Jun 92 - 26 Oct 93	view metadata	download record
BEST 2	515 meters	Aanderaa RCM-8	19 Jun 92 - 26 Oct 93	view metadata	download record
BEST 2	3020 meters	Aanderaa RCM-8	19 Jun 92 - 26 Oct 93	view metadata	download record


BEST 3	205 meters	Aanderaa RCM-8	22 Jun 92 - 28 Oct 93	view metadata	download record
BEST 3	505 meters	Aanderaa RCM-8	22 Jun 92 - 28 Oct 93	view metadata	download record
BEST 3	4950 meters	Aanderaa RCM-8	22 Jun 92 - 28 Oct 93	view metadata	download record


BEST 4	210 meters	Aanderaa RCM-8	23 Jun 92 - 29 Oct 93	view metadata	download record
BEST 4	510 meters	Aanderaa RCM-8	23 Jun 92 - 29 Oct 93	view metadata	download record
BEST 4	3010 meters	Aanderaa RCM-8	23 Jun 92 - 29 Oct 93	view metadata	download record
BEST 4	5130 meters	Aanderaa RCM-8	23 Jun 92 - 29 Oct 93	view metadata	download record

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Description of WOCE component ACM4

The BEST project was designed to shed light on the transport and variablility of the Benguela Current, with particular attention to the ratio of Agulhas Current and South Atlantic Current water masses within the Benguela Current. The experiment involved hydrographic surveys, inverted echo sounders, pressure gauges, and a moored array of current meters (the subject of this data report) - as well as analysis of the TOPEX/POSEIDON satellite altimeter data.

BEST objectives contributed to the WOCE international plan; the current meter array has been identified by WOCE as component ACM-4.

The experiment's PIs were A.L.Gordon and S.L.Garzoli of the Lamont-Doherty Earth Observatory, and R.D.Pillsbury of Oregon State University. Gordon and Garzoli conducted the hydrographic surveys. The echo sounders were operated by Garzoli, and the current meters by Pillsbury.

The positions of the current meters and echo sounders are shown in a map of the region. There is also a vertical section that shows details of the current meter array.

Measurements were made and instruments serviced during three cruises:

BEST 1, 16 June 92 - 5 July 92 (R/V Africana)
BEST 2, 7 May 93 - 3 June 93 (R.R.S. Discovery)
BEST 3, 24 October 93 - 11 November 93 (R/V Maurice Ewing)

The instruments (current meters and echo sounders) were deployed during the BEST 1 cruise and recovered during BEST 3. The four current meter moorings were positioned along 30 deg S in the broad channel between the African continent and Walvis Ridge. Each mooring carried a current meter at a depth of about 200 m and another at 500 m. Three of the moorings had instruments at 3000 m and the two deepest moorings has current meters at about 5000 m.

All of the current meters were Aanderaa RCM8 meters. Data return was good with two exceptions: (a) the speed sensor of the shallow instrument at Mooring 2 failed after about 2 weeks; and (b) the 3000 m instrument at Mooring 3 stopped recording as soon as it entered the water.

Related publications

Clement, A.C., and A.L. Gordon (1995): Velocity structure of the Benguela Current. J. Geophys. Res., 100(C11), 22591-22601.
Garzoli, S. and A.L. Gordon (1996): Origins and variability of the Benguela Current. J. Geophys. Res., 101, 897-906.
Rae, C.M.D., S.L. Garzoli and A.L. Gordon (1996): The eddy field of the southeast Atlantic Ocean: a statistical census from the Benguela Sources and Transports Project. J. Geophys. Res., 101(C5), 11949-11964.
Garzoli, S.L., A.L. Gordon, V. Kamenkovich, D. Pillsbury and C. Duncombe-Rae (1996): Variability and sources of the southeastern Atlantic circulation. J. Marine Res., 54(6), 1039-1071.

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Format of the current records

These files have been compressed with the ZIP compression utility. After downloading them, you will need to expand them. On a PC, WinZip or Pkunzip will do the job. Other utilities are available for the Unix and Macintosh environments. After expansion, you will have ascii files in OSU's stranger format.

The stranger format begins with several lines of header information that are meant to be machine-readable. They contain a Fortran format specification that will be useful in reading the file, a pointer to the first line of data, and a description of the data. Each line of the current record itself contains the time of the sample, the values recorded, and a line count.

Please be aware that end-of-line in these files is a carriage-return plus line-feed (the PC convention). This means that in a Unix environment (where a single line-feed serves as end-of-line) you may want to remove the carriage-returns.

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