Ice Loss and Gravity Dips
Data from an Earth-observing satellite has provided unexpected evidence that ice loss in Antarctica has had a noticeable effect on Earth’s gravity.
The European Space Agency’s Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) launched in March of 2009 and was intended to orbit the Earth for 20 months. Instead, the spacecraft lasted 55 months, and completed its journey by re-entering Earth’s atmosphere in November 2013.
The mission was designed to map Earth’s gravity field, and provided the most accurate gravity model of our planet to date. Gravity at the Earth’s surface varies slightly due to the planet’s rotation and the position of features like mountains and ocean trenches.
Models produced from GOCE data are used to study numerous aspects of our planet, including ocean circulation and changes in sea level. Using the models, scientists can also gain insights into the interior workings of our planet.
GOCE data is invaluable for Earth scientists who study changes in Earth’s climate; but it is also useful for astrobiologists studying the Earth system as a whole in order to understand how our planet became habitable for life, and how habitability might change in the future. This work forms the basis for understanding how and where habitable worlds could develop beyond our solar system.
ESA’s Gravity field and steady-state Ocean Circulation Explorer (GOCE). Credit: ESA
GOCE was not designed to study how gravity changes over time, but by working with data from the satellite, scientists have shown how the loss of mass from glaciers in West Antarctica has left a noticeable signature in our planet’s gravity field. The measurements from GOCE provide much greater detail than previous measurements from missions like the NASA-German Grace satellite.
GOCE data could also be used to validate measurements from other missions, including ESA’s Cryosat satellite, which has been measuring ice loss in Antarctica.
“We are now working in an interdisciplinary team to extend the analysis of GOCE’s data to all of Antarctica,” said Johannes Bouman, of the German Geodetic Research Institute, in a press release from ESA. “This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass.”
GOCE may have ended its mission in 2013, but scientists will study the data returned by the satellite for years to come to provide a greater understanding of the Earth system and environmental changes that our planet may face in the future.
The animation, based on measurements from ESA’s GOCE satellite and the NASA–German Grace mission, shows that ice lost from West Antarctica has caused a dip in Earth’s gravity. Credit: ESA/DGFI/Planetary visions