INTERNAL TIDES OVER THE SANTOS PLATEAU

  • E. G. Morozov Shirshov Institute of Oceanology, Russian Academy of Sciences
DOI 10.29006/1564-2291.JOR-2018.46(1).1
Keywords internal tide, buoy, Santos Plateau, Brazil Basin, numerical modeling, energy decay

Abstract

We analyze internal tides over the Santos Plateau in the South Atlantic. The study is based on the measurements of temperature and currents on the line of moorings normal to the South America coast in the latitudinal band between 28°S and 31°S. The moorings were deployed at distances between 25 and 888 km (from the 500 m isobath) southeast of the continental slope. The instruments were set at 900 m. Numerical modeling revealed the properties of internal tides (amplitudes, wavelength, and decay of amplitudes) along the line of their propagation from the continental slope. The amplitudes of internal tide decrease from the continental slope in the direction to the Vema Channel from 36 m to 15 m. The densities of the energy of tidal internal waves were calculated from the semidiurnal tidal components of current and temperature time series taking into account the vertical gradients of temperature and the Brunt-Väisälä frequency. Decay of the energy of internal tide occurs according to an inverse power law. Numerical modeling of the generation and propagation of internal tides reveals that beams of internal tides are formed near the continental slope. The energy decay based on modeling is similar to the measured data.

References


  1. Egbert G.D. and Erofeeva S. Efficient inverse modeling of barotropic ocean tides. J. Atmos. Ocean Tech., 2002, Vol. 19, pp. 183–204.

  2. Holloway P.E. and Merrifield M.A. Internal tide generation by seamounts, ridges, and islands. J. Geophys. Res., 1999, Vol. 104 (C11), pp. 25937–25951.

  3. Lozovatsky I.D., Morozov E.G., and Fernando H.J.S. Spatial decay of energy density of tidal internal waves. J. Geophys. Res., 2003, Vol. 108 (C6), pp. 3201–3216.

  4. Morozov E.G. Semidiurnal internal wave global field. Deep-Sea Res., 1995, Vol. 42 (1), pp. 135–148.

  5. Morozov E.G. and Vlasenko V.I. Extreme tidal internal waves near the Mascarene Ridge. J. Marine Sys., 1996, Vol. 9 (3-4), pp. 203–210.

  6. Morozov E.G., Demidov A.N., and Tarakanov R.Yu. Transport of Antarctic waters in the deep channels of the Atlantic Ocean. Doklady Earth Sciences, 2008, Vol. 423 (8), pp. 1286–1289.

  7. Morozov E.G. Oceanic Internal Tides, Observations, Modeling and Analysis. A Global View. Dordrecht: Springer, 2018, 316 p.

  8. Pereira A.F. and Castro B.M. Internal tides in the Southwestern Atlantic off Brazil: observations and numerical modeling. J. Phys. Oceanogr., 2007, 37 (6), pp. 1512–1526.

  9. Speer K.G. and Zenk W. The flow of Antarctic Bottom water into the Brazil Basin. J. Phys. Oceanogr., 1993, Vol. 23, pp. 2667–2682.

  10. Torgrimson G.M. and Hikecy B.M. Barotropic and baroclinic tides over the continental slope and shelf off Oregon. J. Phys. Oceanogr., 1999, Vol. 9, pp. 945–961.

  11. Vlasenko V., Stashchuk N., and Hutter K. Baroclinic Tides: Theoretical Modeling and Observational Evidence. Cambridge, Cambridge Univ. Press, 2005, 351 p.

  12. WOD13 (2013) World Ocean Database 2013, Geographically Sorted Data. https://www.nodc.noaa.gov/OC5/WOD/datageo.html; last updated October 26, 2013; last accessed in October 2017.

Published
2018-06-04
Section
Ocean physics and climate

Most read articles by the same author(s)

1 2 > >>