Chapter 8 (Updated): Tidal variations in the Earth's rotation

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  • 22 December 2011
    • The subroutine RG_ZONT2.F has been corrected for a typo in the sine coefficient of the 365.26 day period for delta LOD.[1] The effect is of the order of a ns over the length of a day.

Potential Future Modifications

  • Review of the model for diurnal and semi-diurnal EOP variations


  • ORTHO_EOP.F - Subroutine to compute the diurnal and semidiurnal variations in the Earth orientation. Calls subroutine CNMTX. [2]
  • CNMTX.F - Subroutine called by ORTHO_EOP to compute the time dependent part of the second degree diurnal and semidiurnal tidal potential.[2]
  • RG_ZONT2.F - Subroutine to compute the effects of zonal Earth tides on the rotation of the Earth. Calls subroutine FUNDARG. [3]

[1] Noted by J. Lundberg

[2] Provided by R. Eanes

[3] Provided by R. Gross