Since 2002, two generations of NASA's GRACE satellites have provided important knowledge about the freshwater cycle on Earth. It is a cycle that includes ice and meltwater, among other things, and which has a major impact on the climate system. Now the third generation of GRACE satellites is being manufactured.
The satellites measure changes in the Earth's gravitational field. Gravity varies slightly on Earth, partly because its mass is not evenly distributed. Areas with mountains and ice caps generally have a greater gravity because they have a greater mass locally. This direct correlation between mass distribution and local gravity means that changes such as melting ice can therefore be detected by the satellites.
As a PhD student, Senior Researcher Valentina Barletta from DTU was among the first European researchers to start using data from GRACE 20 years ago. A data source she still uses in her research.
"The GRACE missions are probably one of the most successful missions when it comes to Earth observations. Measurements of gravity provide a unique insight into how the land, ice, and water masses change, and we can monitor how the ice melts and the sea rises," says Valentina Barletta.
