Seasonal fluctuations in the deep central equatorial Atlantic Ocean: a data–model comparison. - Archive ouverte HAL Access content directly
Journal Articles Ocean Dynamics Year : 2006

Seasonal fluctuations in the deep central equatorial Atlantic Ocean: a data–model comparison.

Abstract

Low-frequency current fluctuations in the deep central equatorial Atlantic are analyzed using current meter measurements recorded from November 1992 to November 1994. Current meters were located at about 14°W of longitude and 1° of latitude on both sides of the equator between 1,700 m depth and the ocean bottom. At all sampling depths, the velocity fluctuations are dominantly zonal and symmetrical with respect to the equator. At 1,700 and 2,000 m, the flow is dominated by annual period fluctuations, at 3,000 m, the velocity field amplitude presents a minimum, and at 3,750 and 3,950 m, the flow is modulated by annual and semiannual period variability. The annual signal exhibits an apparent upward phase propagation. When considering the phase and the amplitude of the seasonal fluctuations, the data compare well with the outputs of a realistic numerical simulation of the Atlantic Ocean. Together with a previous analysis of the model simulations, this supports the idea that the observed annual fluctuations are due to wind-forced vertically propagating Kelvin and Rossby waves. Data and model do not provide deciding evidences of the presence of semiannual equatorial waves deeper than 3,500 m depth in the central equatorial Atlantic Ocean.

Domains

Oceanography

Dates and versions

hal-00270709 , version 1 (07-04-2008)

Identifiers

Cite

Virginie Thierry, Herlé Mercie, Anne-Marie Tréguier. Seasonal fluctuations in the deep central equatorial Atlantic Ocean: a data–model comparison.. Ocean Dynamics, 2006, 56 (5-6), pp.581-593. ⟨10.1007/s10236-005-0045-y⟩. ⟨hal-00270709⟩
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