Chapter 7 (Updated): Displacement of reference points
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- 1 February 2018:
- Section 7.1.4 has been rewritten to include the secular pole and remove the former mean pole.
- 31 March 2017:
- In Section 7.1.4 (pg. 16) of chapter text, the last point of observed mean pole values has been corrected to read "epoch (YYYY-1).0". It had been previously written as "YYYY.0".
- 20 December 2016:
- To account of the leap second occurring on 31 December 2016:
- Other Changes:
- An updated CAL2JD.F, a subroutine of DEHANTTIDEINEL.F, was added from the 12th release of the SOFA package.
- 19 June 2015:
- The program HARDISP.F, its subroutine ETUTC.F, the subroutine DEHANTTIDEINEL.F and its subroutine from the SOFA package, DAT.F were updated to account of the leap second occurring on 30 June 2015.
- Corrected Errors:
- Two subroutines of the HARDISP.F package
have been corrected for bugs and the test cases of all affected routines
have been subsequently modified and completed. The potential error on the
HARDISP results is less than 0.1 mm.
- Two variables in ETUTC.F have been changed from single to double precision
- Error in number of seconds/day in the subroutine TDFRPH.F has been corrected. A new test case utilizing non-zero time has been added.
- The test case has been modified in HARDISP.F to utilize non-zero time and correct for the change to double precision in ETUTC.F
- Previously missing data in the test run of the ocean pole tide model was added. An explanatory sentence has been added to section 7.1.5, "Ocean pole tide loading."
- Typos present in the text of the Conventions (2010), have been corrected in the paragraph following Table 7.1 and in Section 7.1.5.
- Two subroutines of the HARDISP.F package have been corrected for bugs and the test cases of all affected routines have been subsequently modified and completed. The potential error on the HARDISP results is less than 0.1 mm.
- Other changes:
- A new version of the IERS Conventional Mean Pole (CMP) is realized in the IERS subroutine, IERS_CMP_2015.F. See Section 7.1.4, "Rotational deformation due to polar motion" for more information. The CMP change also affects the computation of the pole tide effects on the geopotential, see Chapter 6 (Updated).
- An updated CAL2JD.F, a subroutine of DEHANTTIDEINEL.F, was added from the 11th release of the SOFA package.
- 10 June 2013:
- The subroutine DEHANTTIDEINEL.F is corrected for a bug that occurred at the update dated 26 March 2012.  The potential error is below 0.1 mm.
- 24 Dec 2013: The subroutine TDFRPH.F used in the HARDISP package is corrected for an error in the test case. Also, the subroutine TDFRPH2.F has been removed as it was not used.
- 26 March 2012:
The following have been modified to account for the 30 June 2012 leap second:
- The program HARDISP.F, its subroutine ETUTC.F, the subroutine DEHANTTIDEINEL.F and its subroutines from the SOFA package DAT.F and CAL2JD.F have been modified to account for the next leap second to occur 30 June 2012.
- An updated CAL2JD.F, a subroutine of DEHANTTIDEINEL.F, was added from the latest SOFA package. Note that the previous version of DEHANTTIDEINEL.F erroneously did not include the update dated 10 April 2009. This version reinstalls this update (a 0.05 mm effect).
- 14 October 2011:
- The subroutine ARG2.F has been corrected to not modify internally the IYEAR argument (the four-digit year).
- 23 September 2011:
- The subroutine ARG2.F has been corrected for a bug that caused an error for dates starting with year 2000.  Note that the IYEAR argument is now the four-digit year.
Potential Future Modifications
- New section on non-tidal displacement of reference markers
- Section on models for displacement of reference points of instruments rewritten. [Started 10 February 2009]
- DEHANTTIDEINEL.F- Subroutine to compute tidal corrections of station displacements caused by lunar and solar gravitational attraction. (Updated 23 October 2007, 19 February 2009, 10 April 2009, 26 March 2012, 10 June 2013, 19 June 2015) All subroutines needed for compilation are provided on our FTP site.
- HARDISP.F - Program to compute ocean tidal loading from a table of amplitudes and phases of the 11 main tides.  (Updated 19 February 2009, 10 April 2009, 26 March 2012, 19 June 2015) All subroutines needed for compilation are provided on our FTP site.
- ARG2.F - Subroutine to compute the angular argument which depends on time for 11 tidal argument calculations.  This routine replaces the previous routine ARG.f. Main changes are the use of double precision for all variables and of the four-digit year as an input argument.
- IERS_CMP_2015.F - Subroutine to provide estimates of the Conventional Mean Pole.
- annual.pole - Table of yearly mean of pole coordinates from 1976.0 to 2010.0, used to generate the IERS (2010) mean pole model in Section 7.1.4. 
- opoleloadcoefcmcor.txt.gz - Table of coefficients for the ocean pole tide loading model (gzipped). 
- opoleloadcmcor.test - Test run for the ocean pole tide model. 
 Noted by Sha Liu
 Noted by D. Ferguson
 Provided by V. Dehant
 Provided by Duncan Agnew
 From a Table by by E.W. Schwiderski
 Provided by D. Gambis
 Provided by S. Desai