Zuheir Altamimi

The 2013 Vening Meinesz Medal is awarded to Zuheir Altamimi for his invaluable research in the development and continuous improvement of the International Terrestrial Reference Frame and for his important contributions to space geodetic research.

Zuheir Altamimi’s major contribution to space geodesy is the continuous improvement of determining the International Terrestrial Reference Frame (ITRF). The ITRF is the metrological framework that has become indispensible for Earth science applications and for satellite navigation. For the past 30 years, Altamimi has constantly worked to improve the accuracy of the ITRF realisation: its origin, scale, and orientation and the temporal evolution of these defining parameters. Altamimi has been a leader in adopting rigorous mathematical methods to combine diverse multi-center and multi-technique geodetic solutions. His papers on this topic, particularly in the context of the ITRF2005 realisation, are among the most cited articles in space geodesy.

Other aspects of his algorithm development have also received attention, such as imposing inner constraints without distorting the geodetic network. Many geoscience applications, such as measuring sea level rise and its variability in space and time by satellite altimetry, require an accurate terrestrial reference frame at the 1mm level and stability at 0.1mm/yr. To realise this extremely demanding goal, it has been necessary for Altamimi and his group to continuously quantify the metrological performance of the techniques contributing to the ITRF and evaluate their systematic errors. As a result, Altamimi has often played the role of an unbiased referee among the various space geodetic technique services, which has well served the community, ITRF, and end user. Questions of special interest have included quantifying the stability of the satellite-laser-ranging (SLR) frame origin, i.e., the ITRF origin, and the relative scales of SLR and very-long-baseline interferometry frames, upon which the ITRF scale relies. Errors in the local site ties that inter-connect the technique observing networks have received critical attention. The end result has been steady progress in identifying and resolving many outstanding issues in space geodesy. It is easy to take for granted the work that goes into producing a precise and reliable ITRF despite the countless research that relies on the ITRF.

With this medal, the geodetic and geosciences communities recognise Altamimi’s tireless contribution to geoscientific research.