Wednesday, September 14, 2011
GGOS Atmosphere
In modern geodesy and in particular in space geodetic techniques various effects of the atmosphere have to be considered. The atmosphere delays (or advances) radio signals emitted by satellites, e.g. of the GNSS (Global Navigation Satellite Systems), or by distant radio sources observed by VLBI (Very Long Baseline Interferometry), atmosphere pressure loading causes deformation of the Earth's surface up to more than one centimeter (see figure), Earth gravity observations from dedicated satellites have to be reduced for atmospheric influences, and a considerable part of the variations of Earth rotation (polar motion, length of day) is due to processes in the atmosphere. Thus, the atmosphere plays an important role for the Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) with its central theme 'Global deformation and mass exchange processes in the System Earth'.
