Home  >  Work done at ROB(4)

 

The Descartes Prize 2003 has been awarded to the WG on Nutation chaired by Veronique Dehant. This prize is awarded for a fruitful collaboration in Europe and outside Europe, in order to achieve a goal in the frame of Science and Society.
The IAU/IUGG WG on "Nutation for a nonrigid Earth" was awarded a Descartes Prize in 2003 for their development of a new model of the nutations and precession of the Earth. The model was adopted by the International Astronomical Union (IAU) in 2000 and the International Union of Geodesy and Geophysics (IUGG) in 2003. It provides the link between the terrestrial frame, 'fixed' in relation to the Earth's crust and rotating with the Earth, and the celestial frame, which is immobile in space. The relationship between these frames is complicated by the fact that the rotation and orientation of the Earth is subject to irregularities caused by the gravitational pull of the sun and moon, as well as by many other factors that are progressively being identified by geodesists and astronomers. Because the Earth is an ellipsoid flattened at its poles, the combined forces acting upon it produce changes in both the speed of rotation and the orientation of the Earth symmetry axis. The term 'precession' describes the long-term trend of this latter motion, while 'nutation' is the name given to periodic variations, which were the prime focus of the present project.
We have presented this work to the European Union and defended it in front of the Grand Jury. We have learned at the 2003 ceremony that we have been awarded.
The project was coordinated by Prof. Veronique Dehant of the Royal Observatory of Belgium in association with researchers from her institution, from the

• Bureau International des Poids et Mesures in Sevres,
• Institut de Mécanique Céleste et de Calcul des Ephémérides à Paris et l'Observatoire de Paris (France),
• Space Research Centre of the Polish Academy of Sciences in Warsaw (Poland),
• Complutense University of Madrid, the Universities of Alicante and Valladolid (Spain),
• Tehnical Universities of Dresden and Munich and GeoForschungsZentrum Potsdam (Germany),
• Technical University of Vienna (Austria),
• Astronomical Institute of the Academy of Sciences of Czech Republic in Prague (Czech Republic),
• Main Astronomical Observatory of the National Academy of Sciences of Ukraine in Kiev (Ukraine) and
• Sternberg State Astronomical Institute of Moscow State University (Russia).

In addition to these European countries, US, India, Japan, Canada, and China were also participating in the project. Since that time, an advisory board was created; it is composed of Veronique Dehant, Nicole Capitaine, Juan Getino, Harald Schuh, and Aleksander Brzezinski. We have sent a call for proposal for financing PhD students or post-doctoral fellowships. We have received a lot of good proposals and we have decided to finance many subjects. In particular at ROB, there has been several Descartes Nutation Fellows working on different subjects:

• Marta Folgueira (6 months): 'Geophysical effects of considering the new solutions for the Earth's rotation in the framework of the new parameters adopted by the IAU 2000 Resolutions';
• Laurence Koot (2 months): 'Combination of AAM series for a IERS product';
• Laurent Metivier (3 months):'Effect of the internal structure on its loading deformations including rotational deformations such as nutations';
• Marta Folgueira (6 months): 'Impact of tidal Poisson terms on non rigid Earth rotation' and 'Topographic coupling effects on nutations';
• Nicolas Rambaux (6 months): 'Earth's rotation dissipative and excitation mechanisms'.