The Greenland Ice Sheet in 2021

Total Mass Balance Change

For the 25th year in a row, the Greenland Ice Sheet (GrIS) lost ice. The total mass balance (TMB) is calculated by accounting for 1) the surface mass balance (SMB), where accumulation at the top of the ice sheet normally exceeds ablation and 2) ice discharge (D) which is the loss of ice through glacial calving and basal melting where glaciers are in contact with seawater. For the 25th year in a row, the loss of ice from discharge exceeded mass gains from the surface.

There were several notable features and events from the GrIS in 2021:

1. The loss of mass from ice discharge was the largest amount since satellite observations began in 1986.
2. It rained at the top of the GrIS at a station 3216 m above sea level.
3. For the third time in a decade, scientists have observed a melt layer at the station (2021, 2019 and 2012). Melt layers have only been observed 6 times previously over the last 2000 years: 1889, 1094, 992, 758, 753 and 244.

Resources:

[1] "Polar Portal Season Report 2021." http://polarportal.dk/fileadmin/user_upload/PolarPortal/season_report/polarportal_saesonrapport_2021_EN.pdf

[2] "Mass and Height Change". http://polarportal.dk/en/greenland/mass-and-height-change/

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