'Gravity is climate' - 10 years of climate research satellites GRACE

The uneven distribution of mass on and within the planet causes, due the resulting variability of gravity, the earth to have an irregular shape, which deviates significantly from sphericity. 

Known as the "Potsdam Gravity Potato, the geoid has achieved global notoriety but this potato shape is equally subject to temporal changes.

For the first time, the melting of glaciers in Greenland could now be measured with high accuracy from space.

Just in time for the tenth anniversary of the twin satellites GRACE (Gravity Recovery and Climate Experiment) a sharp image has surface, which also renders the spatial distribution of the glacial melt more precisely.

The Greenland ice shield had to cope with up to 240 gigatons of mass loss between 2002 and 2011. This corresponds to a sea level rise of about 0.7 mm per year.

These statements were made possible by the high-precision measurements of the GRACE mission, whose data records result in a hitherto unequaled accurate picture of the earth's gravity. One of Newton's laws states that the gravity of an object depends directly on its mass.

"When the mass of the Greenland ice sheet changes, so does the gravity there," explains Dr. Frank Flechtner from the GFZ German Research Centre for Geosciences.

"The GRACE gravity field measurements therefore give us information on mass changes, including climate-related ones."

But there's more. The uneven distribution of mass on and within the planet causes, due the resulting variability of gravity, the earth to have an irregular shape, which deviates significantly from sphericity.

Known as the "Potsdam Gravity Potato," the geoid has achieved global notoriety. But this potato shape is equally subject to temporal changes.

During the last Ice Age, a mile-thick ice sheet covered North America and Scandinavia. Since the ice melted, the crust, now liberated from its load, continues to rise to this day.

This causes material flow in the earth's interior, in the mantle, to replenish. With GRACE, this glacial-isostatic adjustment can for the first time be accurately detected globally as a change in the geoid height: the ice ages continue to have an effect, which is especially evident in North America and Scandinavia.