The ever-changing Earth

Researchers at the Institute of Geodesy and Geophysics at Vienna University of Technology (TU) are investigating the effects of the Earth's atmosphere on our planet's shape, its rotation and its gravitational field. The Earth's atmosphere is not only essential to support human life on Earth; it also affects our planet's shape, its rotation and its gravitational field. The research project "Global Geodetic Observing System (GGOS) Atmosphere" is a comprehensive and cross-disciplinary study of these complex interrelationships, financed by the Fonds zur Förderung der wissenschaftlichen Forschung (FWF) [The Austrian Science Fund]. The researchers' aim is to develop a better understanding of the Earth's system and to support the development of the Global Geodetic Observing System (GGOS). The Earth's pulse Many different atmospheric influences have to be taken into consideration in modern geodesy, particularly when using space-geodetic techniques. The atmosphere delays radio signals from GPS satellites as well as signals from extragalactic radio sources, which are monitored using the VLBI (Very Long Baseline Interferometry) technique. Atmospheric loads (= air pressure), e.g. during a high pressure weather system, can change the shape of the elastic Earth by up to two centimetres and can also alter the Earth's gravitational force.