Shown above are the monthly changes in ice mass of 8 large drainage basin systems into which the Greenland Ice Sheet can be divided. It can be seen that there are considerable regional differences in the size and timing of the changes of mass in the different basins. The changes in mass here are calculated on the basis of data from the GRACE satellites using the method described in Barletta et al. (2013). The graphs illustrate the month-by-month development in changes of mass measured in gigatonnes, Gt (1 Gt is 1 billion tonnes or 1 km3 of water. 100 Gt correspond to 0.28 mm global sea level rise. Read more.

The map and graph show the gain in the mass of ice when there is precipitation, and how much of this mass is lost when snow and ice melt and when icebergs break off from the ice sheet’s major outlet glaciers. The difference in these mass changes over a glaciological year (September-August) is called the total mass balance of the Greenland Ice Sheet. The map shows the latest changes in mass derived from data from the GRACE and GRACE-FO satellites. The graph illustrates the month-by-month development in changes of mass measured in gigatonnes, Gt (1 Gt is 1 billion tonnes or 1 km3 of water). The left axis on the graph shows how this ice mass loss corresponds to sea level rise contribution. 100 Gt corresponds to 0.28 mm global sea level rise). This data shows that most of the loss of ice occurs along the edge of the ice sheet, where independent observations also indicate that the ice is thinning, that the glacier fronts are retreating in fjords and on land, and that there is a greater degree of melting from the surface of the ice. High on the central region of the ice sheet, however, the GRACE satellites show that there is a small increase in the mass of the ice. Other measurements suggest that this is due to a small increase in precipitation/snowfall. All changes are given relative to April 2002. Based on this data, it can be seen that during the period 2003-2011 the Greenland Ice Sheet has lost 234 km3 of water per year, corresponding to an annual contribution to the mean increase in sea level of 0.65 mm (Barletta et al. (2013). Read more.