Defying Sea Level Rise
March 13, 2024
Insights from the Deep
March 13, 2024The Earth's
True Shape
The true shape of Earth
ESA's GOCE mission has delivered the most accurate model of the 'geoid' ever produced, which will be used to further our understanding of how the Earth works. A precise model of the Earth's geoid is essential for deriving accurate measurements of ocean circulation, sea-level change, and terrestrial ice dynamics. The colours in the image represent deviations in height (–100 m to +100 m) from an ideal geoid. The blue area represent low values, and the red/yellow areas represent high values.
© GOCE, ESA
The surface of the ocean is not as “flat” as it looks. It is influenced by gravity. Where gravity is higher, the ocean surface bulges; in areas with lower gravity, the water surface flattens. The difference between the two areas is up to 150 metres, a key reason that sea level change is not uniform across the globe.
Scientists from Scripps Institute of Oceanography at University California San Diego used altimetry measurements from ESA’s CryoSat mission and from the CNES–NASA Jason-1 satellite to create a new marine gravity map – twice as accurate as the previous version produced nearly 20 years ago. CryoSat’s main task is to measure the elevation of the world’s ice but its altimetry measurements acquired over oceans measure sea-surface height, and this can be used to create global marine gravity models and, from them, eventually derive maps of the seafloor. The new gravity map exposes thousands of previously unchartered seamounts, ridges and deep ocean structures.
© Scripps Institute of Oceanography
Rune Floberghagen
Head of the Climate action, Sustainability and Science department
European Space Agency - ESA
