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Matano, R.P.; Simionato, C.G.; De Ruijter, W.P.; Van Leeuween, P.J.; Strub, P.T.; Chelton, D.B.; Schlax, M.G. "Seasonal variability in the Agulhas Retroflection region" (1999) Geophysical Research Letters. 25(23):4361-4364
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Abstract:

The objective of this article is to present evidence for the existence of seasonal variability in sea surface height (SSH) anomaly in the Agulhas Retroflection region. TOPEX/POSEIDON altimeter data are used to estimate seasonal changes in the mesoscale SSH variability. There is a seasonal oscillation of SSH variability characterized by a maximum during the austral summer and a minimum during the austral winter. The amplitude of this seasonal change is approximately 30% of its mean value. During the winter season the spatial distribution of SSH variability resembles that of the annual mean variability, with relative maxima centered at approximately 18°E, 27°E and 38°E. During the summer there is an additional maximum which extends from approximately 20°E to 25°E and from 40°to 42°S. Analysis of longitude-time diagrams reveals that at low latitudes planetary waves propagate freely throughout the basin. Along the latitude of the Agulhas Retroflection region, the East Madagascar Ridge hampers the westward propagation of planetary waves. It is speculated that the difference between summer and winter patterns is caused by an inertially driven bifurcation of the Agulhas Current. The objective of this article is to present evidence for the existence of seasonal variability in sea surface height (SSH) anomaly in the Agulhas Retroflection region. TOPEX/POSEIDON altimeter data are used to estimate seasonal changes in the mesoscale SSH variability. There is a seasonal oscillation of SSH variability characterized by a maximum during the austral summer and a minimum during the austral winter. The amplitude of this seasonal change is approximately 30% of its mean value. During the winter season the spatial distribution of SSH variability resembles that of the annual mean variability, with relative maxima centered at approximately 18°E, 27°E and 38°E. During the summer there is an additional maximum which extends from approximately 20°E to 25°E and from 40° to 42°S. Analysis of longitude-time diagrams reveals that at low latitudes planetary waves propagate freely throughout the basin. Along the latitude of the Agulhas Retroflection region, the East Madagascar Ridge hampers the west-ward propagation of planetary waves. It is speculated that the difference between summer and winter patterns is caused by an inertially driven bifurcation of the Agulhas Current.

Registro:

Documento: Artículo
Título:Seasonal variability in the Agulhas Retroflection region
Autor:Matano, R.P.; Simionato, C.G.; De Ruijter, W.P.; Van Leeuween, P.J.; Strub, P.T.; Chelton, D.B.; Schlax, M.G.
Ciudad:Washington
Filiación:College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States
Centro de Investigación del Mar y la Atmósfera, Universidad de Buenos Aires, Buenos Aires, Argentina
Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands
College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin. Bldg., Corvallis, OR 97331-5503, United States
Institute for Marine and Atmospheric Research, Utrecht University, POB 80.005, 3508 TA Utrecht, Netherlands
Palabras clave:Climatology; Computer aided analysis; Geodetic satellites; Numerical methods; Satellite observatories; Agulhas retroflection region; Seasonal variability; TOPEX POSEIDON altimeter; Agulhas current; Altimeter data; Austral summers; Planetary Waves; Sea surface height; Seasonal changes; TOPEX/poseidon; Climate change; Surface waters; sea surface height; seasonality; Agulhas Current; Indian Ocean
Año:1999
Volumen:25
Número:23
Página de inicio:4361
Página de fin:4364
DOI: http://dx.doi.org/10.1029/1998GL900163
Título revista:Geophysical Research Letters
Título revista abreviado:Geophys. Res. Lett.
ISSN:00948276
CODEN:GPRLA
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00948276_v25_n23_p4361_Matano

Referencias:

  • Chelton, D.B., Schlax, M.G., Witter, D.L., Richman, J.G., Geosat altimeter observation of the surface circulation of the Southern Ocean (1990) J. Geophys. Res., 95, pp. 17877-17903
  • Ffield, A., Toole, J., Wilson, D., Seasonal circulation in the South Indian Ocean (1997) Geophys. Res. Lett., 24, pp. 2773-2776
  • Garzoli, S.L., Gordon, A.L., Origins and variability of the Benguela Current (1996) J. Geophys. Res., 101, pp. 897-906
  • Goñi, G.J., Garzoli, S.L., Roubicek, A.J., Olson, D.B., Brown, O.B., Agulhas ring dynamics from TOPEX/ POSEIDON satellite altimeter data (1997) J. Mar. Res., 55, pp. 861-883
  • Lutjeharms, J.R.E., Van Ballegooyen, R.C., The retroflection of the Agulhas Current (1988) J. Phys. Oceanogr., 18, pp. 1570-1583
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  • Pearce, A.F., Gründlingh, M.L., Is there a seasonal variation in the Agulhas Current? (1982) J. Mar. Res., 40, pp. 177-184
  • Quartly, G.D., Srokosz, M.A., Seasonal variations in the region of the Agulhas Retroflection: Studies with Geosat and FRAM (1993) J. Phys. Oceanogr., 23, pp. 2107-2124
  • Stramma, L., Lutjeharms, J.R.E., The flow field of the subtropical gyre for the South Indian Ocean (1997) J. Geophys. Res., 102, pp. 55,513-55,530
  • Zlotnicki, V., Fu, L.L., Patzert, W., Seasonal variability in global sea level observed with Geosat altimetry (1989) J. Geophys. Res., 94, pp. 17,959-17,969

Citas:

---------- APA ----------
Matano, R.P., Simionato, C.G., De Ruijter, W.P., Van Leeuween, P.J., Strub, P.T., Chelton, D.B. & Schlax, M.G. (1999) . Seasonal variability in the Agulhas Retroflection region. Geophysical Research Letters, 25(23), 4361-4364.
http://dx.doi.org/10.1029/1998GL900163
---------- CHICAGO ----------
Matano, R.P., Simionato, C.G., De Ruijter, W.P., Van Leeuween, P.J., Strub, P.T., Chelton, D.B., et al. "Seasonal variability in the Agulhas Retroflection region" . Geophysical Research Letters 25, no. 23 (1999) : 4361-4364.
http://dx.doi.org/10.1029/1998GL900163
---------- MLA ----------
Matano, R.P., Simionato, C.G., De Ruijter, W.P., Van Leeuween, P.J., Strub, P.T., Chelton, D.B., et al. "Seasonal variability in the Agulhas Retroflection region" . Geophysical Research Letters, vol. 25, no. 23, 1999, pp. 4361-4364.
http://dx.doi.org/10.1029/1998GL900163
---------- VANCOUVER ----------
Matano, R.P., Simionato, C.G., De Ruijter, W.P., Van Leeuween, P.J., Strub, P.T., Chelton, D.B., et al. Seasonal variability in the Agulhas Retroflection region. Geophys. Res. Lett. 1999;25(23):4361-4364.
http://dx.doi.org/10.1029/1998GL900163