Day-to-day development of the Greenland Ice Sheet with the weather

The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

The figures above are updated on a daily basis and show how much mass in terms of snow, ice or water is lost or gained on the surface of the Ice Sheet.

The black circles on the map correspond to the PROMICE meteorological stations that have been established to monitor the melting processes. Note that the circles on the map are slightly displaced from their actual positions in order for them to be distinguishable. On the large version of the map they are marked with small dots at their true positions. By clicking on the magenta circle, measurements of runoff from Watson river close to Kangerlussuaq is shown. The river drains about 12000 km2 of the inland ice.

The density of snow and ice is different to that of water, and the figures are therefore converted to water to ensure that the total mass is calculated.

The model on which “Daily change” and “Accumulated” are based

The figures are based in part on observations made by meteorological stations on the ice sheet and in part on DMI's research weather model for Greenland, Hirlam-Newsnow, and since 1 July 2017 the HARMONIE-AROME weather model. This data is used in a model that can calculate the total amounts of ice and snow. Snowfall, melting of snow and bare ice, refreezing of melt water and snow that evaporates without melting first (sublimation) are all taken into account in this model.

The model was enhanced in 2014 to take into account the fact that some of the melt water refreezes in the snow, and again in 2015 in order to also take into account the low reflection of sunlight on bare ice compared to snow. Finally, it has been updated again in 2017 with a more advanced representation of percolation and refreezing of meltwater. At the same time, we have extended the reference period to 1981-2010. The update means that the new maps, figures and graphs will deviate from previous examples that can be seen in earlier season reports. Everything that appears on this page, however, is calculated using the same model, such that all graphs and values are directly comparable.

Data from the meteorological stations may be missing due to problems with instruments or transmissions via satellite if the power of the solar-powered battery is low or if the meteorological station is covered in snow, or, in the worst case, has toppled over.

More information:

PROMICE

This year's data for the total contribution can be downloaded here. Please make sure that you read the disclaimer at the top of the file!

Surface mass balance and other model output from DMI's regional climate model HIRHAM5 as shown on the daily surface mass balance page is freely available for research purposes from the DMI research department. A selection of variables for the ERA-Interim period and future simulations driven by EC-Earth can be downloaded here. These simulations are documented in scientific publications by Langen et al. (2017) and Mottram et al. (2017).

The HIRLAM weather model

The HARMONIE-AROME weather model that since 1 July 2017 drives the melt model