Ice front and flow speed variations of marine-terminating outlet glaciers along the coast of Prudhoe Land, northwestern Greenland

Daiki Sakakibara,Shin Sugiyama

doi:10.1017/jog.2018.20

Abstract

ABSTRACTSatellite images were analyzed to measure the frontal positions and ice speeds of 19 marine-terminating outlet glaciers along the coast of Prudhoe Land, northwestern Greenland from 1987 to 2014. All the studied glaciers retreated over the study period at a rate of between 12 and 200 m a−1, with a median (mean) retreat rate of 30 (40) m a−1. The glacier retreat began in the year ~2000, which coincided with an increase in summer mean air temperature from 1.4 to 5.5 °C between 1996 and 2000 in this region. Ice speed near the front of the studied glaciers ranged between 20 and 1740 m a−1 in 2014, and many of them accelerated in the early 2000s. In general, the faster retreat was observed at the glaciers that experienced greater acceleration, as represented by Tracy Glacier, which experienced a retreat of 200 m a−1 and a velocity increase of 930 m a−1 during the study period. A possible interpretation of this observation is that flow acceleration induced dynamic thinning near the termini, resulting in enhanced calving and rapid retreat of the studied glaciers. We hypothesize that atmospheric warming conditions in the late 1990s triggered glacier retreat in northwestern Greenland since 2000.

Highlights

Mass loss from the Greenland ice sheet has been increasing since the 1990s, resulting in an enhanced contribution to sea-level rise (e.g., Rignot and others, 2008, 2011; Shepherd and others, 2012)
We present a comprehensive dataset of recent changes in ice front positions and ice speed fields of marine-terminating outlet glaciers located along the coast of Prudhoe Land, northwestern Greenland (Fig. 1)
All the 19 studied glaciers retreated at a rate ranging from 12 to 200 m a−1 between the 1980s and 2014, having median and mean retreat rates of 30 and 44 m a−1, respectively

Summary

Introduction

Mass loss from the Greenland ice sheet has been increasing since the 1990s, resulting in an enhanced contribution to sea-level rise (e.g., Rignot and others, 2008, 2011; Shepherd and others, 2012). Satellite observations and surface mass-balance modelling have demonstrated that the recent mass loss from the Greenland ice sheet is driven by two processes: increases in surface melting and ice discharge from outlet glaciers (Rignot and others, 2008, 2011; van den Broeke and others, 2009; Sasgen and others, 2012; Enderlin and others, 2014). A future projection of ice discharge from the Greenland ice sheet is still crucial for understanding the magnitude and timing of global sea-level rise. An understanding of the mechanisms controlling glacier dynamics is crucial for predicting both the response of the Greenland ice sheet to climate change and future sea-level rise (Church and others, 2013)

Results

Discussion

Conclusion