Chapter 6 (Updated): Geopotential

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All content in the updated pages should be considered under development and are not definitive nor officially approved as a registered edition. For the official IERS Conventions (2010), please download the packaged v 1.0.0.

Updates

  • 1 February 2018:
    • Reference to mean pole has been replaced with mean figure axis.
    • Other minor changes to the text in Section 6.1.
  • 10 August 2012:
    Changes with respect to previous version of the chapter:
    • A clarification has been added to section 6.3.2 "Ocean tide models", part "FES2004", specifying how the zonal terms should be treated to consistently obtain Stokes coefficients.
  • 14 October 2011:
    Main changes with respect to previous version of the chapter:
    • Corrected errors in fes2004_Cnm-Snm.dat: Coefficients for the waves Sa and P1 were computed with an erroneous phase.
    • In the section 6.3.2 "Ocean tide models", part "FES2004", there is an ongoing discussion on the phase of the C20 term of the very long period waves (pi/2 as per the update of 23 September 2011 or -pi/2). A warning sentence has been inserted in the text. The same warning applies to the values in the first two data lines of the files fes2004.dat and fes2004_Cnm-Snm.dat, which remain as in the update of 23 September 2011.
  • 23 September 2011:
    Main changes with respect to previous version of the chapter:
    • Corrected an error in the file fes2004_Cnm-Snm.dat: The unit of coefficients is 10^-11.
    • In the section 6.3.2 "Ocean tide models", part "FES2004", the phase of the C20 term of the very long period waves has been corrected to pi/2.[1] The corresponding changes are introduced in the first two data lines of the files fes2004.dat and fes2004_Cnm-Snm.dat.

Additional Information

Tide models:
  • fes2004.dat - Tide height coeeficients of the main waves of FES2004, see Section 6.3 for details.[1]
  • fes2004_Cnm-Snm.dat - Harmonic coefficients of the main waves of FES2004 computed from the tide height coefficients, see Section 6.3 for details.
  • S1.dat - Tide height coefficients of wave S1 for FES2004, see Section 6.3 for details. [1]

[1] Provided by R. Biancale

[2] Provided by S. Desai