Wednesday, April 6, 2011

Earth’s gravity revealed in unprecedented detail


GOCE Geoid
New GOCE geoid (credit: ESA/HPF/DLR)
Scientists at the Institute for Astronomical and Physical Geodesy at the Technische Universität München haveunveiled the most accurate model of the geoid ever produced.
The geoid is the surface of an ideal global ocean in the absence of tides and currents, shaped only by gravity. After two years in orbit, the European Space Agency’s GOCE satellite has gathered enough data on the geoid to map Earth’s gravity with unparalleled precision. GOCE orbits at the lowest altitude of any observation satellite in order to gather the most accurate data on Earth’s gravity. It uses an ion engine to generate tiny forces that compensate for drag.
A precise model of Earth’s geoid is crucial for deriving accurate measurements of ocean circulation, sea-level change, and terrestrial ice dynamics. The geoid is also used as a reference surface from which to map the topographical features on the planet. The ESA researchers say that a better understanding of variations in the gravity field will lead to a deeper understanding of Earth’s interior, such as the physics and dynamics associated with volcanic activity and earthquakes.
The new geoid was unveiled March 31 at the Fourth International GOCE User Workshop hosted at the Technische Universität München in Munich, Germany.

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