IGCP 565 Project Workshop
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IGCP 565 Workshop 1: Science of geodetic monitoring of the hydrological cycle |
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Abstract:
Inversions of Geodetic Observations: Current Resolution, Accuracy and Challenges
Xiaoping Wu
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
Ice ages, Late-Pleistocene deglaciation, present-day non-steric sea level
change, Greenland and Antarctic ice mass fluctuations and land hydrological
cycles are all prominent examples of global surface mass variations in the
fluid layer of the Earth. Physically distinguishable geodetic signatures
of such variations including gravity, ocean topography and displacement of
the solid Earth surface are currently measured with ever increasing
precision by the GRACE, Topex/Jason/OSTM satellite missions and surface
geodetic networks of SLR/VLBI/GPS. The complementary and overlapping
information content contained in these data makes it very clear that data
combination offers the best chance for signature separation, more complete
spatiotemporal coverage and resolution, and cross technique data validation.
In this presentation, we will demonstrate quantitatively the power of such
data combination in providing a global monitoring capability with more
complete spatiotemporal spectrum, and enhanced resolution, and accuracy. The
time rates of change in many geodetic data contain a multitude of signatures
due to present-day surface mass trend, glacial isostatic adjustment (GIA)
and tectonic motions. Data combination in this case offers a unique chance
to separate and resolve them and allow us to understand the different
underlying geophysical causes better. We will show that although some
separation can be achieved for the secular signatures, a better
understanding requires continued missions, significant ground infrastructure
improvement, and more data in strategic locations.
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