• Beardsley, R. C., , Candela J. , , Limeburner R. , , Geyer W. R. , , Lentz S. J. , , Castro B. M. , , Cacchione D. , , and Carneiro N. , 1995: The m2 tide on the Amazon shelf. J. Geophys. Res., 100 , C2,. 22832319.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bloomfield, P., 1976: Fourier Analysis of Time Series: An Introduction. John Wiley & Sons, 258 pp.

  • Broomhead, D. S., , and King G. P. , 1986: Extracting qualitative dynamics from experimental data. Physica, 20D , 217236.

  • Caldwell, P., 1998: Sea level data processing on IBM-PC compatible computers. Joint Archive for Sea Level of the National Oceanography Data Center and University Hawaii Sea Level Center, Tech. Rep. JIMAR Contribution 98-319, 80 pp.

  • Cartwright, D., 1968: An unified analysis of tides and surges round north and east Britain. Philos. Trans. Roy. Soc. London, 15.

  • Cartwright, D. E., 2000: Tides: A Scientific History. Cambridge University Press, 292 pp.

  • Colebrook, J. M., 1978: Continuous plankton records: Zooplankton and environment, North–East Atlantic and North Sea, 1948–1975. Oceanol. Acta, 1 , 923.

    • Search Google Scholar
    • Export Citation
  • Foreman, M. G. G., 1978: Manual for tidal currents analysis and predictions. Pacific Marine Science Rep. 78−6, Institute of Ocean Sciences, Patricia Bay, Sidney, BC, Canada, 57 pp.

  • Franco, A., 1981: Tides: Fundamentals, analysis and prediction. Institute de Pesquisas Tecnologicas do Estado de Sao Paulo, Publ. 1182, 232 pp.

  • Ghil, M., and Coauthors, 2002: Advanced spectral methods for climatic time series. Rev. Geophys., 40 .1003, doi:10.1029/2000RG000092.

  • Gibson, J. F., , Farmer D. , , Casdagli M. , , and Eubank S. , 1992: An analytic approach to practical state space reconstruction. Physica D, 57 , 130.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Godin, G., 1972: The Analysis of Tides. University of Toronto Press, 264 pp.

  • Huang, N. E., and Coauthors, 1998: The empirical mode decomposition and the Hilbert spectrum for non-linear and non-stationary time series analysis. Proc. Roy. Soc London, A454 , 903995.

    • Search Google Scholar
    • Export Citation
  • Jay, A. D., , and Flinchem E. P. , 1999: A comparison of methods for analysis of tidal records containing multi-scale non-tidal background energy. Cont. Shelf Res., 19 , 16951732.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jay, D. A., , and Kukulka T. , 2003: Revising the paradigm of tidal analysis—The uses of non-stationary data. Ocean Dyn., 53 , 110125.

  • Johns, W. E., , Lee T. N. , , Schott F. A. , , Zantopp R. J. , , and Evans R. H. , 1990: The North Brazil Current retroflection: Seasonal structure and eddy variability. J. Geophys. Res., 95 , C12,. 22 10322 120.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Munk, W., , and Cartwright D. , 1966: Tidal spectroscopy and prediction. Philos. Trans. Roy. Soc. London, A259 , 533581.

  • Pawlowicz, R., , Beardsley B. , , and Lentz S. , 2002: Classical tidal harmonic analysis including error estimates in Matlab using T_TIDE. Comput. Geosci., 28 , 929937.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pugh, D., 1987: Tides, Surges and Mean Sea-Level. A Handbook for Engineers and Scientists. John Wiley & Sons, 472 pp.

  • Santos, M. S., 1999: Descrição de corpos arenosos de grande escala na zona costeira e na plataforma continental norte do Rio Grande do Norte por imagens TM/Landsat. M.S. thesis, Division of Remote Sensing, Instituto Nacional de Pesquisas Espaciais, INPE-7010-TDI/658, 123 pp.

  • Signorini, S. R., , and Miranda L. B. , 1983: Tidal and low-frequency currents near the shelf-break: Northeastern coast of Brazil. J. Phys. Oceanogr., 13 , 21072115.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Testa, V., , and Bosence W. J. , 1999: Physical and biological controls on the formation of carbonate and silicate bedforms on the northeast Brazilian shelf. Sedimentology, 46 , 279301.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vianna, M., , Solewicz R. , , Cabral A. , , and Testa V. , 1991: Sandstream on the northeast Brazilian shelf. Cont. Shelf Res., 11 , 509524.

  • Vianna, M., , Cabral A. , , and Gherardi F. , 1993: TM-Landsat imagery applied to the study of the impact of global climate change on a tropical coastal environment during the last deglaciation. Int. J. Remote Sens., 14 , 29712983.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vianna, M. L., , and Menezes V. V. , 2003: A seasonal and interannual study of the western equatorial Atlantic upper thermocline circulation variability. Interhemispheric Water Exchange in the Atlantic Ocean, G. Goni and P. Malanotte-Rizolli, Eds., Oceanographic Series, Vol. 68, Elsevier, 137–174.

    • Search Google Scholar
    • Export Citation
  • WOCE, 2002: WOCE global data, version 3.0. WOCE International Project Office, Tech. Rep. 180/02, DVD 1 and 2.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 50 50 7
PDF Downloads 42 42 6

Singular Spectrum Analysis of Nonstationary Tidal Currents Applied to ADCP Data from the Northeast Brazilian Shelf

View More View Less
  • 1 Instituto Nacional de Pesquisas Espaciais, and VM Oceanica Ltda, Sao Jose dos Campos, Sao Paulo, Brazil
  • | 2 VM Oceanica Ltda, Sao Jose dos Campos, Sao Paulo, Brazil
© Get Permissions
Restricted access

Abstract

The development of new tools for the analysis of nonstationary currents, including tidal currents, has been the subject of recent research. In this work a method for studies of nonstationary barotropic or baroclinic currents based on empirical orthogonal function (EOF) and singular spectrum analysis (SSA) is proposed. It represents a new alternative to other methods of analysis of tidal currents in strong interaction with nontidal forcing, for example, the continuous wavelet transform. The advantage of the SSA method resides in the fact that it is fast, easy to implement, efficient for short-time records, and is based on the covariance structure of the data. If significant tidal constituents occur in the measurements, these are determined by the method itself even with short-time-series records. This is in contrast to the harmonic analysis (HA), where a large table of tidal constituents stated a priori are fitted to the data, even if the presence of some of these are spurious and not justified physically. The method is first demonstrated in the analysis of a synthetic current time series and then applied to an hourly current ADCP profile dataset of 410 days from the northeast Brazilian shelf. In both cases the SSA results were compared to the classical HA and the neoclassical short-term HA (STHA). The description of the shelf area where the ADCP was placed, the deployment and data acquisition operations, and the quality control data analysis are included for completeness. Analysis of the full ADCP quality-controlled data was done after a separation of the subtidal from the tidal high-frequency bands, although this traditional separation is not strictly necessary and was only made to better compare with HA and STHA. Analysis of the tidal band obtained from the ADCP data showed that the extracted tidal ellipse constituents present coherent oscillations dominated by the annual and 57-day periods, and changes in the sense of rotation of the current vector from anticyclonic to cyclonic in the ellipses. The subtidal band variability is shown to be also dominated by an annual and a 57-day period component, both polarized along the isobaths, which is suggestive of a nonlinear interaction of the subtidal and the tidal variability.

Corresponding author address: M. Vianna, CIP/INPE, Instituto Nacional de Pesquisas Espaciais, Av. Dos Astronautas 1758, S. J. Campos, SP 12227-010, Brazil. Email: marcio@vmoceanica.com.br

Abstract

The development of new tools for the analysis of nonstationary currents, including tidal currents, has been the subject of recent research. In this work a method for studies of nonstationary barotropic or baroclinic currents based on empirical orthogonal function (EOF) and singular spectrum analysis (SSA) is proposed. It represents a new alternative to other methods of analysis of tidal currents in strong interaction with nontidal forcing, for example, the continuous wavelet transform. The advantage of the SSA method resides in the fact that it is fast, easy to implement, efficient for short-time records, and is based on the covariance structure of the data. If significant tidal constituents occur in the measurements, these are determined by the method itself even with short-time-series records. This is in contrast to the harmonic analysis (HA), where a large table of tidal constituents stated a priori are fitted to the data, even if the presence of some of these are spurious and not justified physically. The method is first demonstrated in the analysis of a synthetic current time series and then applied to an hourly current ADCP profile dataset of 410 days from the northeast Brazilian shelf. In both cases the SSA results were compared to the classical HA and the neoclassical short-term HA (STHA). The description of the shelf area where the ADCP was placed, the deployment and data acquisition operations, and the quality control data analysis are included for completeness. Analysis of the full ADCP quality-controlled data was done after a separation of the subtidal from the tidal high-frequency bands, although this traditional separation is not strictly necessary and was only made to better compare with HA and STHA. Analysis of the tidal band obtained from the ADCP data showed that the extracted tidal ellipse constituents present coherent oscillations dominated by the annual and 57-day periods, and changes in the sense of rotation of the current vector from anticyclonic to cyclonic in the ellipses. The subtidal band variability is shown to be also dominated by an annual and a 57-day period component, both polarized along the isobaths, which is suggestive of a nonlinear interaction of the subtidal and the tidal variability.

Corresponding author address: M. Vianna, CIP/INPE, Instituto Nacional de Pesquisas Espaciais, Av. Dos Astronautas 1758, S. J. Campos, SP 12227-010, Brazil. Email: marcio@vmoceanica.com.br

Save