Total mass change
This page illustrates the total change in mass of the Greenland Ice Sheet. Here you can follow how the ice sheet gains mass through snowfall accumulating on the surface and how it shrinks through melting from the surface and discharge of icebergs from glaciers that end in the sea.
- The map illustrates the latest GRACE satellite-derived mass changes.
- The curve shows the change in the total mass balance month by month measured in gigatonnes (1 Gt is 1 billion tonnes or 1 km3 of water. 100 Gt corresponds to 0.28 mm global sea level). All mass changes are relative to June 2006.
The figures are based on monthly measurements of changes in gravity. Gravity changes as the amount of ice changes and this can be detected by the GRACE satellites. Scientists at DTU Space have contributed to developing the methods used to derive ice mass changes from the gravity changes. The raw GRACE satellite data is carefully processed and validated before it is released to the user, and the product presented here might be delayed by 2-3 months. See Barletta et al. 2013.
The map illustrates the latest monthly mass change map derived from the GRACE satellite data. The curve illustrates the total mass change month by month measured in gigatonnes (1 Gt is 1 billion tonnes or 1 km3 of water. 100 Gt corresponds to 0.28 mm global sea level).
The GRACE data reveal that most of the ice loss has been from the areas near the ice sheet margins where other observations show ice thinning, glacier retreat on land and in fjords, and increased surface melting. High in the ice sheet interior, GRACE satellite measurements show a slight ice mass gain that is again consistent with other measurements of slightly increased snowfall.
Overall, the Greenland Ice Sheet has during 2003-2011 on average seen a net annual ice loss corresponding to 234 km3 of water. Or approximately 0.65 mm in average annual contribution to global sea level rise (Barletta et al. 2013).
Origin of data
The gravity data comes from the NASA and German Aerospace Center (DLR) GRACE mission. Data are processed at different processing centers, which provide monthly models of the gravity field to the user. These monthly models are processed after Barletta et al. (2013) to derive ice mass changes.
More about the GRACE-mission
The Gravity Recovery And Climate Experiment (GRACE) is a joint NASA-DLR satellite mission. The GRACE twin satellites were launched in March 2002, and they are orbiting Earth, approximately 500 km above Earth. The two satellites are separated by approximately 200 km in space and the relative distance between the two is measured very accurately and this information is used to derive monthly, global models of the Earth’s gravity field.