ICM1 (ACE)

The Agulhas Current Experiment (ACE) produced data from 17 mechanical current meters and 2 ADCPs on 5 moorings. You can view metadata and download current records by clicking on links in the table below. Each current record is identified in the table by its depth and the name of the mooring. If you do download any of the records you should review the note on file format. A brief description of the experiment also is available. You may want to look at a map of the array to see where the moorings were, or at a vertical section that shows array details. From here you can also move up one level to the list of WOCE experiments.

Note that the two ADCP records at Moorings B and C have been subsampled: the shallowest bins were too noisy to be useful, and we have included here a subset of the remainder in which individual bins are separated by 48 meters. Most of the ADCP time series contain many short interpolations to fill gaps in which the signal was poor. Some of the longer interpolations are predictive but most are linear and involve only one or two data points.

mooringinstr depthinstr typedatesmetadatadownload
Mooring B 168 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 216 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 264 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 312 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 360 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 408 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 424 meters ADCP 03 Mar 95 - 21 Mar 96 view metadata download record
Mooring B 430 meters FSI current meter 04 Mar 95 - 18 Apr 95 view metadata download record
Mooring C 56 meters ADCP 03 Mar 95 - 15 Apr 95 view metadata download record
Mooring C 104 meters ADCP 03 Mar 95 - 18 Apr 95 view metadata download record
Mooring C 152 meters ADCP 03 Mar 95 - 19 Apr 95 view metadata download record
Mooring C 200 meters ADCP 03 Mar 95 - 19 Apr 95 view metadata download record
Mooring C 248 meters ADCP 03 Mar 95 - 19 Apr 95 view metadata download record
Mooring C 296 meters ADCP 03 Mar 95 - 19 Apr 95 view metadata download record
Mooring C 344 meters ADCP 03 Mar 95 - 19 Apr 95 view metadata download record
Mooring C 358 meters Aanderaa RCM 03 Mar 95 - 28 Nov 95 view metadata download record
Mooring C 789 meters FSI current meter 03 Mar 95 - 07 Jun 95 view metadata download record
Mooring C 1156 meters Aanderaa RCM 03 Mar 95 - 20 Apr 96 view metadata download record
Mooring C 1967 meters Aanderaa RCM 03 Mar 95 - 20 Apr 96 view metadata download record
Mooring D 375 meters Aanderaa RCM 02 Mar 95 - 17 Apr 96 view metadata download record
Mooring D 855 meters Aanderaa RCM 02 Mar 95 - 17 Apr 96 view metadata download record
Mooring D 1191 meters Aanderaa RCM 02 Mar 95 - 17 Apr 96 view metadata download record
Mooring D 1955 meters Aanderaa RCM 02 Mar 95 - 17 Apr 96 view metadata download record
Mooring E 401 meters Aanderaa RCM 01 Mar 95 - 18 Apr 96 view metadata download record
Mooring E 804 meters Aanderaa RCM 01 Mar 95 - 18 Apr 96 view metadata download record
Mooring E 1201 meters Aanderaa RCM 01 Mar 95 - 18 Apr 96 view metadata download record
Mooring E 2028 meters Aanderaa RCM 01 Mar 95 - 17 Dec 95 view metadata download record
Mooring F 365 meters Aanderaa RCM 28 Feb 95 - 16 May 95 view metadata download record
Mooring F 755 meters Aanderaa RCM 28 Feb 95 - 18 Apr 96 view metadata download record
Mooring F 1172 meters Aanderaa RCM 28 Feb 95 - 18 Apr 96 view metadata download record
Mooring F 1982 meters Aanderaa RCM 28 Feb 95 - 21 Dec 95 view metadata download record

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Brief description of ICM1

As a UK contribution to the international Indian Ocean survey carried out during 1995-96, an array of 6 moorings with 26 current meters was deployed across the Agulhas Current curing a two-week cruise aboard RRS DISCOVERY, 26 February to 9 March 1995, Durban to Capetown.

The Agulhas Current is the thermocline western boundary current for the South Indian Ocean and it has long been considered to be the strongest of the Southern Hemisphere western boundary currents. Direct measurements of its size and temporal variablility, however, had never been made; and arguments over the appropriate choice of reference level for geostrpohic transport estimates from hydrographic sections have led to a range of transport values from 35 to 95 Sv for the region where it closely follows the African continental slope. An accurate estimate of the transport of the Agulhas Current is a key to defining the large-scale circulation of the Indian Ocean. Thus, the primary objective for DISCOVERY Cruise 214 was to deploy this array of moored current meters, labelled ICM1 in international WOCE plans, to measure the transport and variability of the Agulhas Current over a year-long period.

The current meter array was recovered on cruises aboard R/V ALGOA in April-May 1996. The four offshore moorings (C, D, E, F) were recovered intact. The innermost mooring (A) had been dragged by a fishing trawler in mid deployment and as a result had lost its buoyancy. Dragging operations for mooring A were unsuccessful. Mooring B also was not recovered during the initial cruise despite dragging operations. Just after returning to the UK, the mooring team was recalled to South Africa to rejoin ALGOA and recover the drifing top of Mooring B located by ARGOS transmissions. Only the uppermost ACDP and FSI current meter were recovered from Mooring B. Thus, of the 26 current meters deployed in the Agulhas Current, 19 were recovered: 15 Aanderaa, 2 FSI and 2 ADCP instruments.

Related publications

Bryden, H. L., et al (1995): RRS Discovery Cruise 214, 26 Feb to 09 Mar 1995, Agulhas Current Experiment. Institute of Oceanographic Sciences Cruise Report No. 249, 85p.

Bryden, H.L. (1995): Agulhas Current Experiment (ACE). Sigma, the UK WOCE Newsletter, 16, 6-7.

Beal, L. M., and H. L. Bryden (1997): Observations of an Agulhas Undercurrent. Deep-Sea Research I, 44(9/10), 1715-1724.

Beal, L. M. (1997): Observations of the Velocity Structure of the Agulhas Current. PhD thesis, Department of Oceanography, University of Southampton, 158p.

Beal, L. and H. Bryden (1999): The velocity and vorticity structure of the Agulhas Current at 32S. J. Geophys. Res., 104(C3), 5151-5176.

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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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