************************************************************************
IERS Message No. 223                                    January 16, 2013
************************************************************************


Information on the updates to the IERS Conventions (2010)


The IERS Conventions Center informs of the following updates:

15 January 2013

* Chapter 9 "Models for atmospheric propagation delays" has been
updated, see http://tai.bipm.org/iers/convupdt/convupdt_c9.html .

Changes are the following:

- Introduce the model Global Pressure and Temperature 2 in sections 9.2
  "Tropospheric model for radio techniques" and 9.3 "Sources for
  meteorological data" (provided by J. Boehm). 

- In the section 9.4 "Ionospheric models for radio techniques", correct
  some numerical values in a number of equations for using exact CODATA
  (2010) values of fundamental constants (noted by R. Langley). Changes
  are not significant with respect to the uncertainties of the
  quantities.

* Appendix E with the IUGG Resolution 3 Adopted at the XXVth General
Assembly (2012), has been added, see
http://tai.bipm.org/iers/convupdt/convupdt_ap.html .


The USNO web site http://maia.usno.navy.mil/conv2010/convupdt.html has
similarly been updated.

Gerard Petit and Brian Luzum
IERS Conventions Center


************************************************************************
IERS Messages are edited and distributed by the IERS Central Bureau.
If not stated otherwise, the IERS is only the distributor of the message
and is not responsible for its content.
To submit texts for distribution and to subscribe or unsubscribe,
please write to <central_bureau@iers.org>.
Archives: http://www.iers.org/Messages/
************************************************************************