Large spatial variations in the flux balance along the front of a Greenland tidewater glacier

Abstract. The frontal flux balance of a medium-sized tidewater glacierin western Greenland in the summer is assessed by quantifying the individual components (ice flux, retreat, calving, and submarinemelting) through a combination of data and models. Ice flux and retreat are obtained from satellite data. Submarinemelting is derived using a high-resolution ocean model informed by near-ice observations, and calving is estimated using a record of calving events along the ice front. All terms exhibit large spatial variabilityalong the  ∼ 5 km wide ice front. It is found that submarinemelting accounts for much of the frontal ablation in small regions where two subglacial discharge plumes emerge at the ice front. Away from the subglacial plumes, the estimated melting accounts for a small fraction of frontal ablation. Glacier-wide, these estimates suggest that mass loss is largely controlled by calving. This result, however, is at odds with the limited presence of icebergsat this calving front – suggesting that melt rates in regions outside of the subglacial plumes may be underestimated. Finally, we argue that localized melt incisions into the glacierfront can be significant drivers of calving. Our results suggest a complex interplay of melting and calving marked by high spatial variabilityalong the glacierfront.