Western boundary current variability off french-guiana as observed from moored current measurements
| Type | Article | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Date | 1994 | ||||||||
| Language | English | ||||||||
| Author(s) | Colin C, Bourles B, Chuchla R, Dangu F | ||||||||
| Source | Oceanologica Acta (0399-1784) (Gauthier-Villars), 1994 , Vol. 17 , N. 4 , P. 345-354 | ||||||||
| WOS© Times Cited | 10 | ||||||||
| Abstract | Moored current measurements carried out from 31 March 1990 to 15 September 1991 in two stages at a point (near 6 degrees N) located over the mid-continental slope off French Guiana are presented. Six current meters were positioned between 200 and 2700 m depth. Upper level mean current data showed a northwestward flowing North Brazil Current (NBC) with mean velocity values decreasing from 10 cm/s in the range 200-250 m to almost zero at 800 m depth, the level of the Antarctic Intermediate Waters. In the range 500-800 m, the current reversed in spring in the presence of the southeastward Western Boundary Under Current (WBUC); the mean velocity from February to June 1991 is around 2 cm/s. Deep currents over the continental rise show a strong southeastward Deep Western Boundary Current extending from around 1000 m depth to the bottom (3000 m depth in this case) with mean core speeds of 20 cm/s at 2000-2070 m depth. Transport estimates based on these data and a few Pegasus sections for the mean vertical and lateral extensions of the DWBC yield a value of 21 x 10(6) m(3)/s at that location. Low-frequency current fluctuations were dominated by a well-defined 50- to 70-day period oscillation with peak-to-peak northwestward velocity amplitude of around 90 cm/s at the upper level. The mean vertical eddy kinetic energy distribution showed an abrupt decrease of the energy down to 800 m depth and a slight decrease below and down to the bottom. | ||||||||
| Full Text |
|