[IGSMAIL-6193] REFAG

[Harald Schuh]

Dear Colleagues,

We would like to draw your attention to the

Session 4, Interaction of Celestial and Terrestrial Reference Frames,

a part of the

IAG Commission 1 Symposium 2010 on Reference Frames for Applications
in Geosciences (REFAG2010)

which will be held at Marne la Vallee, France on 4-8 October 2010

Session description:

The main objective of this session is the study of the interactions between
the celestial and the terrestrial reference frames (CRF and TRF) with a
special focus on the consistency between the frames. This covers
theoretical aspects of the celestial reference system and systematic
effects in the CRF determination. The celestial and the terrestrial
ephemeris origin replaced in 2003 the vernal equinox and the traditional
first axis of the terrestrial intermediate frame. Consequently, the Earth
rotation angle replaced the apparent sidereal time. The Earth orientation
parameters (EOP) connect the CRF and the TRF. Some effects or modelling
errors which can be expressed in both frames, e.g. atmospheric gradients,
can systematically affect each of the frames. Other effects affect only one
frame directly but - if not modelled there correctly - can still be
transcribed as deformation of the other frame or change of the Earth
orientation parameters. W.r.t. theory the effects of the most recent IAU
definitions (2006), the relation between the barycentric system (as
realized by VLBI) and the geocentric system shall be studied. Additionally,
effects which systematically affect source positions are to be identified.
This includes the comparison of various CRF realizations, effects of
geodetic datum definition on VLBI-determined CRF, effects of meteorological
data on VLBI-determined CRF, and effects of various analysis options on
VLBI-determined CRF.

As for the celestial reference frames the second realization of the ICRF
was approved at the XXVIIth IAU General Assembly in 2009. First survey of
the new ICRF-2 will be reported. Concerning highly precise optical
celestial reference frames, upcoming optical astrometry space missions such
as GAIA (Global Astrometry Interferometer for Astrophysics) and SIM (Space
Interferometer Mission) will significantly enhance the quality of the
optical catalogues in terms of position precision and number of stars.

Finally, the interaction between the celestial and terrestrial reference
frame and the transformation between both shall be studied with the goal to
improve the consistency between celestial reference frames, a terrestrial
reference frame and the EOP. This includes the effect of errors in the CRF
on the terrestrial reference frame and vise versa, the realization of the
NNR-condition for the ITRF (e.g. the influence of deformations). The
interaction between the frames and the EOP determination, the effect of
various geophysical models, and the interaction with the gravity field can
also be reported.

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Please consider submitting a paper for this session or contact us directly
if you have any questions.

Please note the submission deadline 31 July, and the registrtation deadline
31 August.

More details on REFAG2010 can be found at the meeting Web page
http://iag.ensg.ign.fr/index.php?id=140

Looking forward to seeing you in Paris,


Session conveners:
Harald Schuh, harald.schuh at tuwien.ac.at
Sebastien Lambert, sebastien.lambert at obspm.fr
Chopo Ma, chopo.ma at mail.nasa.gov
Zinovy Malkin, malkin at gao.spb.ru



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Prof. Dr. Dr. h.c. Harald Schuh
Advanced Geodesy
Institute of Geodesy and Geophysics (E128)
TU Wien
Gusshausstr. 27-29
1040 Wien
AUSTRIA

Tel. +43-1-58801-12860
Fax. +43-1-58801-12896
harald.schuh at tuwien.ac.at