Evidence for the maintenance of slowly varying equatorial currents by intraseasonal variability
Greatbatch, Richard J.
Tuchen, Franz Philip
Toole, John M.
Farrar, J. Thomas
MetadataShow full item record
KeywordEquatorial deep jets; Seasonal cycle; Momentum flux convergence; Tropical instability waves; Equatorial basin mode resonance
Recent evidence from mooring data in the equatorial Atlantic reveals that semiannual and longer time scale ocean current variability is close to being resonant with equatorial basin modes. Here we show that intraseasonal variability, with time scales of tens of days, provides the energy to maintain these resonant basin modes against dissipation. The mechanism is analogous to that by which storm systems in the atmosphere act to maintain the atmospheric jet stream. We demonstrate the mechanism using an idealized model setup that exhibits equatorial deep jets. The results are supported by direct analysis of available mooring data from the equatorial Atlantic Ocean covering a depth range of several thousand meters. The analysis of the mooring data suggests that the same mechanism also helps maintain the seasonal variability.
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Geophysical Research Letters 45 (2018): 1923–1929, doi:10.1002/2017GL076662.
Suggested CitationArticle: Greatbatch, Richard J., Claus, Martin, Brandt, Peter, Matthießen, Jan-Dirk, Tuchen, Franz Philip, Ascani, Francois, Dengler, Marcus, Toole, John M., Roth, Christina, Farrar, J. Thomas, "Evidence for the maintenance of slowly varying equatorial currents by intraseasonal variability", Geophysical Research Letters 45 (2018): 1923–1929, DOI:10.1002/2017GL076662, https://hdl.handle.net/1912/10226
The following license files are associated with this item:
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 International
Showing items related by title, author, creator and subject.
Local and equatorial forcing of seasonal variations of the North Equatorial Countercurrent in the Atlantic Ocean Yang, Jiayan; Joyce, Terrence M. (American Meteorological Society, 2006-02)The seasonal variation of the North Equatorial Countercurrent (NECC) in the tropical Atlantic Ocean is investigated by using a linear, one-layer reduced-gravity ocean model and by analyzing sea surface height (SSH) data ...
Export fluxes of calcite in the eastern equatorial Pacific from the Last Glacial Maximum to present Loubere, Paul; Mekik, Figen; Francois, Roger; Pichat, Sylvain (American Geophysical Union, 2004-06-12)The eastern equatorial Pacific (EEP) is an important center of biological productivity, generating significant organic carbon and calcite fluxes to the deep ocean. We reconstructed paleocalcite flux for the past 30,000 ...
Moored current meter data from the Atlantic north equatorial countercurrent near 6°N 28°W (September, 1983-March, 1984) : vol. XXXVI Levy, Ellen; Richardson, Philip L. (Woods Hole Oceanographic Institution, 1984-09)This report presents current and wind data from the second of three surface mooring deployments in the Atlantic North Equatorial Countercurrent near 6°N and 28°W. A Vector Averaging Wind Recorder (VAWR) measured wind ...