Extended Data Fig. 3: Climatology of the SMB and its components.
Climatology of the surface mass balance (SMB) and its components snowfall and melt runoff in ACN (a, c, and e, respectively) and SVA (b, d, and f, respectively) for 1950–2019 as represented by MAR3.11 forced by ERA5. The mean is depicted as coloured line, the variability as grey area (dark: one standard deviation; light: two standard deviations). It is discernible that the surface mass balance fluctuations for both regions are determined by the variability of the melt production in the summer months JJA. Relative contribution of the SMB components shown in a-f to the variability of the annual mass balance for g, ACN and h, SVA. The variability of each component is estimated as the standard deviation with respect to the climatological mean for the years 1950–2019. Discharge variability is assumed to be ± 15% of the mean discharge rate of 4.3 Gt yr-1 (ACN) and 5.2 Gt yr-1 (SVA) based on Blasczyk et al.6. It is visible that melt runoff is the dominant contributor to interannual variability, accounting for 75% (ACN) and 66% (SVA) of the variability of the annual mass balance. Note that SMB highly correlates with melt runoff (-0.98 for ACN and -0.89 for SVA) and to a lesser extent with snowfall (0.50 for ACN and 0.48 for SVA).
