Following one year of gravitational data collection, the European Space Agency’s GOCE satellite has produced what the ESA says is the most accurate model of the Earth’s geoid ever produced. A geoid is, essentially, a surface that describes the way the Earth’s oceans would shake out if there were no tides or currents and if the oceans could travel over continents: If gravity was all that mattered. (Wikipedia has a more rigorous definition.) As you can see in the animation above (h/t Bad Astronomy), it is quite a lumpy fellow.
ESA:
[The geoid] is a crucial reference for measuring ocean circulation, sea-level change and ice dynamics – all affected by climate change.
…
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. In addition, 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.
(ESA, Bad Astronomy via Cindy Au)
