Seasonal ice-speed variations in 10 marine-terminating outlet glaciers along the coast of Prudhoe Land, northwestern Greenland

• Published in: Journal of Glaciology
• Main Authors: Sakakibara, Daiki, Sugiyama, Shin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2019
• Subjects: glacier; Greenland; Journal of Glaciology; Prudhoe land; Sea ice
• Online Access: http://dx.doi.org/10.1017/jog.2019.81; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143019000819

Abstract We present a 3-year record of seasonal variations in ice speed and frontal ablation of 10 marine-terminating outlet glaciers along the coast of Prudhoe Land in northwestern Greenland. The glaciers showed seasonal speedup initiated between late May and early June, and terminated between late June and early July. Ice speed subsequently decreased from July to September. The timing of the speedup coincided with the onset of the air temperature rise to above freezing, suggesting an influence of meltwater availability on the glacier dynamics. No clear relationship was found between the speedup and the terminus position or the sea-ice/ice-mélange conditions. These results suggest that the meltwater input to the glacier bed triggered the summer speedup. The excess of summer speed (June–August) over the mean for the rest of the year accounted for 0.5–13% of the annual ice motion. Several glaciers showed seasonal frontal variations, i.e. retreat in summer and advance in winter. This was not due to ice-speed variations, but was driven by seasonal variations in frontal ablation. The results demonstrate the dominant effect of glacier surface melting on the seasonal speedup, and the importance of seasonal speed patterns on longer-term ice motion of marine-terminating outlet glaciers in Greenland.