Some 1,200 Participants of the European Space Agency’s (ESA) Living Planet Symposium in Bergen, Norway, got a first glimpse today of a geoid map produced by GOCE, ESA’s Gravity Field and Steady-State Ocean Circulation Explorer.
Image: ESA – Colours show the height differences – in metres – in an idealized motionless global ocean due to density anomalies in the Earth’s interior.
The Earth’s geoid, a concept first described by 19th century German mathematician Carl Friedrich Gauss, is a visualization of what the idealized planetary surface would look like if the force of gravity was everywhere perpendicular – like in a global ocean without tides and currents.
GOCE, launched in March 2009, is measuring Earth’s gravity with unprecedented accuracy and resolution. The so-produced maps and data could help scientists precisely measure changes in ocean circulation, sea-level and ice caps – all of which are affected by climate change.
“With each two-month cycle of data, the gravity model will become more detailed and accurate,” says Reiner Rummel, chairman of the GOCE mission advisory group.
As gravitational variations are stronger closer to Earth, GOCE orbits at an altitude of merely 255 kiolmetres – the lowest of any Earth observation satellite. To counter the effect of strong residual air, which would otherwise quickly decay its orbit, the satellite engine continuously fires xenon ions at high velocities.
“The gravity measuring system is functioning extremely well. The system is actively compensating for the effects of atmospheric drag and delivering a continuous set of clean gravity readings,” says GOCE mission manager Rune Floberghagen Floberghagen.
The final gravity map and geoid model is to advance research in a broad range of fields, from oceanography to geodesy and earthquake research.