[22 December 2008] GGOS and geodesy monitor sea level: The Newsletter of the Information Zentrum Sydney of the DAAD reported in its Issue 13 of December 2008 on the "Annual Alumni and Scholarship Holder Meeting in November". One of the presentations at this meeting was given by the IAG Vice President Chris Rizos with the title "What Geodesy can tell us about Sea Level Rise". The Newletter reports on page 3 the following about this presentation:

"Chris Rizos: What Geodesy can tell us about Sea Level Rise

Geodesy is the science of measuring and mapping the geometry, orientation and gravity field of the Earth including the associated variations with time. Modern Geodesy involves a range of space and terrestrial technologies that contribute to our knowledge of the solid earth, atmosphere and oceans. These technologies include: Global Positioning System/Global Navigation Satellite Systems (GPS/GNSS), Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), Satellite Altimetry, Gravity Mapping Missions such as GRACE, CHAMP & GOCE, satellite-borne Differential Interferometric Synthetic Aperture Radar (DInSAR), Absolute and Relative Gravimetry, Precise Surveying (Levelling & Traversing).

The Global Geodetic Observing System (GGOS) is an important component of the International Association of Geodesy (IAG). GGOS aims to integrate all geodetic observations in order to generate a consistent high quality set of geodetic parameters for monitoring the phenomena and processes within the 'System Earth'. Integration implies the inclusion of all relevant information for parameter estimation, implying the combination of geometric and gravimetric data, and the common estimation of all the necessary parameters representing the solid Earth, the hydrosphere (including oceans, ice-caps, continental water), and the atmosphere.

Chris’ presentation focused on the contribution geodetic space techniques are making to: (a) define the reference frame, (b) measure global sea level rise using Satellite Altimetry, (c) monitor the stability of tide gauges that measure the local differential change in sea-land level, (d) separating the sea level rise from thermal expansion from that of ice melt effects (which change the gravity field), and (e) making accurate determinations of coastal Digital Elevation Models for coastal zone vulnerability studies.

Humboldt alumnus Professor Chris Rizos holds a Doctor of Philosophy in Satellite Geodesy and is Head of the School of Surveying & Spatial Information Systems at UNSW as well as the Vice President of the above mentioned IAG."