SCM9 (SWINDEX)

SWINDEX (the Southwest Indian Ocean Experiment) produced 20 current meter records and 2 thermistor chain records from 5 moorings. You can view metadata and/or download the records by clicking on links in the tables below. Each current meter or thremistor chain record is identified in the tables by its depth and the name of the mooring. 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. 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.

Current meters

mooringinstr depthinstr typedatesmetadatadownload
Mooring A 330 meters Aanderaa RCM5 12 Apr 93 - 20 Jun 94 view metadata download record
Mooring A 533 meters Aanderaa RCM5 12 Apr 93 - 07 Jan 94 view metadata download record
Mooring A 634 meters Aanderaa RCM7 12 Apr 93 - 27 Jan 95 view metadata download record
Mooring A 1360 meters Aanderaa RCM5 12 Apr 93 - 27 Jan 95 view metadata download record
Mooring A 2223 meters Aanderaa RCM8 12 Apr 93 - 27 Jan 95 view metadata download record
Mooring A 2818 meters Aanderaa RCM8 12 Apr 93 - 27 Jan 95 view metadata download record
Mooring B 311 meters Aanderaa RCM5 09 Apr 93 - 18 Dec 94 view metadata download record
Mooring B 612 meters Aanderaa RCM8 09 Apr 93 - 26 Jan 95 view metadata download record
Mooring B 1529 meters Aanderaa RCM5 09 Apr 93 - 26 Jul 93 view metadata download record
Mooring D 335 meters Aanderaa RCM5 06 Apr 93 - 23 Jan 95 view metadata download record
Mooring D 638 meters Aanderaa RCM7 06 Apr 93 - 23 Jan 95 view metadata download record
Mooring D 1364 meters Aanderaa RCM5 06 Apr 93 - 24 Jan 95 view metadata download record
Mooring F 382 meters Aanderaa RCM5 03 Apr 93 - 29 Jun 93 view metadata download record
Mooring F 683 meters Aanderaa RCM7 03 Apr 93 - 20 Jan 95 view metadata download record
Mooring F 1391 meters Aanderaa RCM5 03 Apr 93 - 20 Jan 95 view metadata download record
Mooring F 2661 meters Aanderaa RCM8 03 Apr 93 - 20 Jan 95 view metadata download record
Mooring F 4174 meters Aanderaa RCM8 03 Apr 93 - 20 Jan 95 view metadata download record
Mooring G 1411 meters Aanderaa RCM5 01 Apr 93 - 18 May 93 view metadata download record
Mooring G 2681 meters Aanderaa RCM8 01 Apr 93 - 18 Jan 95 view metadata download record
Mooring G 5812 meters Aanderaa RCM8 01 Apr 93 - 18 Jan 95 view metadata download record

Thermistor chains

mooringinstr depthinstr typedatesmetadatadownload
Mooring A 331-430 meters Aanderaa TC 12 Apr 93 - 20 Dec 94 view metadata download record
Mooring D 336-435 meters Aanderaa TC 6 Apr 93 - 23 Oct 94 view metadata download record

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Description of SWINDEX

The Southwest Indian Ocean Experiment entailed hydrographic surveys and an array of current meters. The hydrographic studies were undertaken on DISCOVERY cruises 201 and 213, with the goal of ascertaining whether any part of the Antarctic Circumpolar Current passes north of or across the Crozet Plateau. An array of current meter moorings (which also carried two thermistor chains) was deployed on and near the crest of the Plateau (see map).

Seven moorings designated A through G were installed in April 1993. Five moorings were recovered 22 months later. All of the instruments, including the thermistor chains, were manufactured by Aanderaa. RCM5 current meters were used at shallower depths, and RCM7s and RCM8s at the deeper levels.

Processing notes: (1) RCM5s record a speed value obtained by averaging over the sampling interval, but measure direction instantaneously at the end of the interval. In order to mitigate the mismatch between speed and direction (severe because of the long sampling interval), each speed was paired with a direction obtained by averaging the direction recorded at the end of the interval, with the previous recorded direction. This type of correction was not required for the RCM7s and RCM8s, which are vector-averaging instruments. (2) When the speed rotor stalled the speed was set equal to the stall speed, which was as low as 1.1 cm/sec for some of the current meters and as high as 2.2 cm/sec for others.

The hydrographic data referred to above can be found at the WOCE Hydrographic Program Office (WHPO) with expocodes 74DI201_1 and 74DI213_1, the 4th and 7th occupations of area ISS1.

Related publications

Pollard, R.T., J.F. Read et al (1994): RRS Discovery Cruise 201, 23 Mar - 3 May 1993. South West Indian Ocean Experiment (SWINDEX). IOSDL Cruise Report 240, 96pp.

Pollard, R.T., J.F. Read et al (1995): RRS Discovery Cruise 213, 6 Jan - 21 Feb 1995. South West Indian Ocean Experiment (SWINDEX). IOSDL Cruise Report 247, 104pp.

Pollard, R. and J. Read (1996): Current measurements in SWINDEX. In Understanding ocean circulation: UK WOCE: the first six years (ed. R. Pollard and D. Smythe-Wright). Southampton: Southampton Oceanography Centre. 32pp.

Pollard, R. and J. Read (1997): Two-year long current time series from the southwest Indian Ocean. International WOCE Newsletter, 29, 3-7.

Read, J.F. and R. T. Pollard (1999): Deep inflow into the Mozambique Basin. J. Geophys. Res. 104 (C2), 3075-3090.

Pollard, R.T. and J.F. Read (2001): Circulation pathways and transports of the Southern Ocean in the vicinity of the Southwest Indian Ridge. J. Geophys. Res., 106(C2), 2881-2898.

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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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