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IERS Message No. 61 September 1, 2004
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AGU Fall Meeting - Call for Papers
In the geodesy program of the AGU Fall Meeting (San Francisco, December
13-17, 2004) some sessions are particularly relevant for
the IERS. We strongly encourage your participation in presentations
and discussions during this meeting (descriptions here below). The full
program and more information are available at:
Please note that the deadline for online submission of abstracts is
September 9.
Questions or information requests can be sent to Olivier de Viron,
e-mail: o.deviron@oma.be
G02: Geophysical Synergies From Combinations of Independent Geodetic
Results
One advantage of a system of multiple, independent geodetic observing
techniques is the potential to produce combined products that provide
improved geophysical insights compared to any single method in terms of
accuracy, precision, resolution, reliability, or other property. This
session will focus on studies demonstrating this potential or clarifying
the limitations of such approaches. Examples include improved
tropospheric monitoring using combined GPS, VLBI, and DORIS path delay
estimates, more accurate Earth orientation estimates using
multi-technique combinations, improved spatial resolution of surface
deformations using GPS and InSAR jointly, etc. The emphasis here is on
the enhancements to geophysical understanding that can be derived rather
than on the mechanics of combinations strategies, although papers on
this aspect are also welcome. Identification of any weaknesses in the
current networks of observing systems and ideas to address them are
appropriate as well.
G03: Earth Rotation Variations and Geocenter Motion
Space-geodetic techniques are used to monitor precisely the Earth's
rotation and the motion of its center of mass. These techniques perform
observations relating terrestrial sites to extra-terrestrial objects.
The motions of the terrestrial and celestial fiducial objects are
modelled taking into account the knowledge of plate tectonics and
deformations, solar system dynamics, quasars physics (VLBI), the Earth
gravity field (SLR, DORIS, GPS) and other effects. On the other hand,
the dynamics of the global fluids (atmosphere, ocean, hydrosphere, ...)
is also monitored and its influence on the the observed motions can be
modelled. The session topics will include the observation of these
variations and motions at long as well as short timescales, the
modelling involved in the analysis of observations and the effects of
geophysical fluids.
G09: Reference Frame Procedures in Practice to Enhance Scientific
Investigations
We solicit scientific investigators to present papers on the actual
practice of reference frames to specific scientific problems. Scientific
investigators do not necessarily apply the same conventional reference
frame procedure to all scientific problems, but often apply various
procedures appropriate to the signal under investigation. Reasons for
selecting a specific procedure might be to improve signal to noise ratio
in station coordinate time series, or to simplify the scientific
interpretation by a physically useful choice of datum, or to simplify
the analysis in cases where the choice of frame is irrelevant.
Scientists often do not require accurate determination of station
positions, but they more generally do require very precise knowledge of
station kinematics. Reference frame procedures appropriate to the study
of seasonal loading signals might be more relaxed than studies that also
require scientific interpretation of secular loading signals. Frames
used in practice for the study of secular tectonics might not be the
same as those for the study of secular loading or GIA. Depending on the
situation, frames procedures that produce globally-reference coordinate
time series (such as fiducial-free precise point positioning) may be
more or less effective for scientific interpretation of tectonics than
regionally-filtered coordinate time series. We welcome papers that
present results on the application of reference frame procedures to
specific scientific problems, and also papers that discuss the
effectiveness of different possible procedures appropriate to scientific
problems over a wide variety of spatial and temporal scales. Our
definition of 'reference frame procedure' is intended to be broad,
including spatial and temporal filtering schemes.
G12: Time-Variable Gravity: Observations, Analyses, and Implications
The Earth is a dynamic system - it has a fluid, mobile atmosphere and
oceans, a continually changing distribution of ice, snow, and
groundwater, a fluid core undergoing hydromagnetic motion, a mantle
undergoing both thermal convection and rebound from glacial loading of
the last ice age, and mobile tectonic plates. These processes affect the
distribution of mass in the Earth and produce variations in the Earth's
gravitational field on a variety of spatial and temporal scales. Highly
accurate measurements of the Earth's gravity field made with appropriate
spatial and temporal sampling can thus be used to better understand the
processes that move mass within the Earth, and on and above its surface.
This session will address the measurement of time-varying gravity and
their interpretation, particularly as it applies to the solid Earth,
ocean and hydrosphere, cryosphere, atmosphere and the interactions
between the various components of the Earth system. Results from
multi-satellite laser ranging and GRACE, as well as expected findings
from future missions, such as GOCE, are encouraged.
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