Editorial Type:
Article
Article Type:
Research Article

An Improved Gaussian Jet Model for Deriving Absolute Geostrophic Velocity from Satellite Altimetry

Seung-Bum Kim Department of Space and Climate Physics, University College London, London, United Kingdom

Search for other papers by Seung-Bum Kim in
Current site
Google Scholar
PubMed Close
and
M. A. Saunders Department of Space and Climate Physics, University College London, London, United Kingdom

Search for other papers by M. A. Saunders in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Dec 2002
DOI:
https://doi.org/10.1175/1520-0426(2002)019<2020:AIGJMF>2.0.CO;2
Page(s):
2020–2029
Restricted access

Abstract

Key aspects of a Gaussian jet model for deriving absolute geostrophic velocity from TOPEX/Poseidon altimeter data are improved. Velocities are obtained by synthesizing Gaussian fits to cross-stream velocity anomaly profiles of the Kuroshio and its extension for the 3-yr period from October 1992. Significant meanders in the Kuroshio Extension are fitted using supplementary information on the jet position obtained from temperature frontal data. Contrary to the findings of earlier studies, the performance of the Gaussian jet model is sensitive to the details of the filter employed in presmoothing the altimeter data. It is found that a Gaussian filter with a full width at half-maximum of 63 km is optimal for minimizing the difference in the mean sea surface height between the model and observations.

Current affiliation: Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, Daejeon, South Korea

Corresponding author address: Dr. S. B. Kim, Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, SaTReC/KAIST, 373-1, Gusung, Yusung, Daejeon, 305-701, South Korea. Email: sbkim@satrec.kaist.ac.kr

Abstract

Key aspects of a Gaussian jet model for deriving absolute geostrophic velocity from TOPEX/Poseidon altimeter data are improved. Velocities are obtained by synthesizing Gaussian fits to cross-stream velocity anomaly profiles of the Kuroshio and its extension for the 3-yr period from October 1992. Significant meanders in the Kuroshio Extension are fitted using supplementary information on the jet position obtained from temperature frontal data. Contrary to the findings of earlier studies, the performance of the Gaussian jet model is sensitive to the details of the filter employed in presmoothing the altimeter data. It is found that a Gaussian filter with a full width at half-maximum of 63 km is optimal for minimizing the difference in the mean sea surface height between the model and observations.

Current affiliation: Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, Daejeon, South Korea

Corresponding author address: Dr. S. B. Kim, Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, SaTReC/KAIST, 373-1, Gusung, Yusung, Daejeon, 305-701, South Korea. Email: sbkim@satrec.kaist.ac.kr

Save
Cover Journal of Atmospheric and Oceanic Technology
Journal of Atmospheric and Oceanic Technology

  • AVISO, 1996: User handbook for merged TOPEX/Poseidon products. Doc. AVI-NT-02-101-CN, 3d ed. CNES, Toulouse, France, 196 pp.

  • Bryden, H. L., Roemmich D. H. , and Church J. A. , 1991: Ocean heat transport across 24°N in the Pacific. Deep-Sea Res., 38 , 297–324.

  • Challenor, P. G., Read J. F. , Pollard R. T. , and Tokmakian R. T. , 1996: Measuring surface currents in the Drake Passage from altimetry and hydrography. J. Phys. Oceanogr., 26 , 2748–2759.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Chelton, D. B., Ries J. C. , Haines B. J. , Fu L-L. , and Callahan P. S. , 2001: Satellite altimetry. Satellite Altimetry and Earth Sciences, L.-L. Fu and A. Cazenave, Eds., Academic Press, 1–131.

    • Search Google Scholar
    • Export Citation

  • Chu, P. C., 1995: P-vector method for determining absolute velocity from hydrographic data. Mar. Technol. Soc. J., 29 , 3–14.

  • Chu, P. C., and Fan C. , 1998: P-vector inverse method evaluated using the Modular Ocean Model (MOM). J. Oceanogr., 54 , 185–198.

  • Ebuchi, N., and Hanawa K. , 1995: Comparison of surface current variations observed by Topex altimeter with TOLEX-ADCP data. J. Oceanogr., 51 , 351–362.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Ebuchi, N., and Hanawa K. , 2000: Mesoscale eddies observed by TOLEX-ADCP and TOPEX/Poseidon altimeter in the Kuroshio recirculation region south of Japan. J. Oceanogr., 56 , 43–57.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Ebuchi, N., and Hanawa K. , 2002: Influence of mesoscale eddies on variations of the Kuroshio path south of Japan. J. Oceanogr., in press.

    • Search Google Scholar
    • Export Citation

  • Feron, R. C. V., De Ruijter W. P. M. , and van Leeuwen P. J. , 1998: A new method to determine the mean sea surface dynamic topography from satellite altimeter observations. J. Geophys. Res., 103 , 1343–1362.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Gille, S. T., 1994: Mean sea-surface height of the Antarctic Circumpolar Current from Geosat data—Method and application. J. Geophys. Res., 99 , 18255–18273.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Grose, T. J., Bigg G. R. , and Johnson J. A. , 1994: The Bernoulli inverse method—Theory and practice. Deep-Sea Res., 41 , 767–785.

  • Hall, M. M., 1989: Velocity and transport structure of the Kuroshio Extension at 35°N, 152°E. J. Geophys. Res., 94 , 14445–14459.

  • Hanawa, K., Yoshikawa Y. , and Taneda T. , 1996: TOLEX-ADCP monitoring. Geophys. Res. Lett., 23 , 2429–2432.

  • Imawaki, S., Uchida H. , Ichikawa H. , Fukasawa M. , and Umatani S. , AKUSA Group,. 1997: Time series of the Kuroshio transport derived from field observations and altimetry data. International WOCE Newsletter, No. 25, WOCE International Project Office, Southampton, United Kingdom, 15–18.

    • Search Google Scholar
    • Export Citation

  • Ishikawa, Y., Awaji T. , Akitomo K. , and Qiu B. , 1996: Successive correction of the mean sea surface height by the simultaneous assimilation of drifting buoy and altimetric data. J. Phys. Oceanogr., 26 , 2381–2397.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Joyce, T. M., Kelly K. A. , Schubert D. M. , and Caruso M. J. , 1990: Shipboard and altimetric studies of rapid Gulf Stream variability between Cape Cod and Bermuda. Deep-Sea Res., 37 , 897–910.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Kelly, K. A., and Gille S. T. , 1990: Gulf Stream surface transport and statistics at 69°W from the Geosat altimeter. J. Geophys. Res., 95 , 3149–3161.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Kelly, K. A., and Qiu B. , 1995: Heat flux estimates for the western North Atlantic. Part II: The upper-ocean heat balance. J. Phys. Oceanogr., 25 , 2361–2373.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Kelly, K. A., Joyce T. M. , Schubert D. M. , and Caruso M. J. , 1991: The mean sea surface height and geoid along the Geosat subtrack from Bermuda to Cape Cod. J. Geophys. Res., 96 , 12699–12709.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Kelly, K. A., Singh S. , and Hwang R. X. , 1999: Seasonal variations of sea surface height in the Gulf Stream region. J. Phys. Oceanogr., 29 , 313–327.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Killworth, P. D., 1986: A Bernoulli inverse method for determining the ocean circulation. J. Phys. Oceanogr., 16 , 2031–2050.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Kim, S. B., 1998: Upper ocean heat balance over the northwest Pacific heat balance analysed using in-situ, model and satellite data. Ph.D. thesis, University College London, London, United Kingdom, 310 pp.

    • Search Google Scholar
    • Export Citation

  • Levitus, S., and Boyer T. P. , 1994: Temperature. World Ocean Atlas 1994, Vol. 4. NOAA Atlas NESDIS4, 117 pp.

  • Marshall, J. C., 1985: Determining the ocean circulation and improving the geoid from satellite altimetry. J. Phys. Oceanogr., 15 , 330–349.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Mitsuzawa, K., and Holloway G. , 1998: Characteristics of deep currents along trenches in the northwest Pacific. J. Geophys. Res., 103 , 13085–13092.

  • Porter, D. L., Glenn S. M. , Dobson E. B. , and Crowley M. F. , 1996: Extension and validation of a Gulf Stream synthetic geoid. J. Atmos. Oceanic Technol., 13 , 514–531.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Qiu, B., 1992: Recirculation and seasonal change of the Kuroshio from altimetry observations. J. Geophys. Res., 97 , 17801–17811.

  • Qiu, B., 1995: Variabilities and energetics of the Kuroshio Extension and its recirculation gyre from the first two-year TOPEX data. J. Phys. Oceanogr., 25 , 1827–1842.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Qiu, B., 2000: Interannual variability of the Kuroshio Extension system and its impact on the wintertime SST field. J. Phys. Oceanogr., 30 , 1486–1502.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Qiu, B., Kelly K. A. , and Joyce T. M. , 1991: Mean flow and variability in the Kuroshio Extension from Geosat altimetry data. J. Geophys. Res., 96 , 18491–18507.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Rapp, R. H., and Yi Y. , 1994: A TOPEX/Poseidon reference ground track. TOPEX/Poseidon Research News, No. 2, Jet Propulsion Laboratory. 15–17.

    • Search Google Scholar
    • Export Citation

  • Snaith, H. M., 1993: A simple iterative method to improve Geosat along track sea surface height data. Int. J. Remote Sens., 14 , 1715–1722.

  • Stommel, H., and Schott F. , 1977: The beta spiral and the determination of the absolute velocities in different oceans from hydrographic station data. Deep-Sea Res., 24 , 325–329.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Tapley, B. D., Chambers D. P. , Shum C. K. , Eanes R. J. , and Ries J. C. , 1994: Accuracy assessment of the large-scale dynamic ocean topography from TOPEX/Poseidon altimetry. J. Geophys. Res., 99 , 24605–24617.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • van Leeuwen, P. J., 1999: The time-mean circulation in the Agulhas region determined with the ensemble smoother. J. Geophys. Res., 104 , 1393–1404.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Willebrand, J., Käse R. H. , Stammer D. , Hinrichen H. H. , and Kraus W. , 1990: Verification of Geosat sea surface topography in the Gulf Stream Extension with surface drifting buoys and hydrographic measurements. J. Geophys. Res., 95 , 3007–3014.

    • Crossref
    • Search Google Scholar
    • Export Citation

  • Wunsch, C., 1977: Determining the general circulation of oceans: A preliminary discussion. Science, 196 , 871–875.

  • Wunsch, C., and Gaposchkin E. M. , 1980: On using satellite altimetry to determine the general circulation of the ocean with application to geoid improvements. Rev. Geophys., 18 , 725–745.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 458 234 20
PDF Downloads 99 34 3