Fig. 1: Glacier mass change in ACN and SVA.
a,b, Time series of mass change from GRACE/GRACE-FO satellite data (dark coloured lines; April 2002 to April 2021) and MAR3.11 SMB-D* (light coloured lines; April 2002 to December 2019) of ACN (a) and SVA (b). Vertical lines indicate the end of GRACE and start of the GRACE-FO science data operations. The GRACE/GRACE-FO uncertainties in a and b are shown as one standard deviation (±1σ; dark grey) and two standard deviations (±2σ; light grey) (Methods). Time series were shifted along the ordinate by an arbitrary offset. SMB-D* data for 2013 (yellow dotted line in b) include an estimate of the mass loss of 4.4 ± 0.8 Gt (ref. 25) related to the Austfonna surge event. The respective rate of mass change from GRACE/GRACE-FO for 2002–2021 (polynomial fit of order n = 1) is indicated in a and b. c, The specific annual mass-balance anomalies from GRACE/GRACE-FO for 2003–2020, detrended with the rate of mass change for 2002–2021, are juxtaposed for ACN (blue) and SVA (red) with ±1σ uncertainties. A biennial mass balance is estimated for 2017 and 2018 to bridge the GRACE/GRACE-FO data gap. For clarity, an intermittent bar indicates the value for SVA for the period 2013–2014, including the Austfonna surge event. d, The geographic locations of the glaciers. The specific mass balance is the mass balance divided by the glacier area of 105,000 km2 for ACN and 34,000 km2 for SVA.
