Analysis of Antarctic Peninsula glacier frontal ablation rates with respect to iceberg melt-inferred variability in ocean conditions

M C Dryak,E M Enderlin

doi:10.1017/jog.2020.21

Abstract

AbstractMarine-terminating glaciers on the Antarctic Peninsula (AP) have retreated, accelerated and thinned in response to climate change in recent decades. Ocean warming has been implicated as a trigger for these changes in glacier dynamics, yet little data exist near glacier termini to assess the role of ocean warming here. We use remotely-sensed iceberg melt rates seaward of two glaciers on the eastern and six glaciers on the western AP from 2013 to 2019 to explore connections between variations in ocean conditions and glacier frontal ablation. We find iceberg melt rates follow regional ocean temperature variations, with the highest melt rates (mean ≈ 10 cm d−1) at Cadman and Widdowson glaciers in the west and the lowest melt rates (mean ≈ 0.5 cm d−1) at Crane Glacier in the east. Near-coincident glacier frontal ablation rates from 2014 to 2018 vary from ~450 m a−1at Edgeworth and Blanchard glaciers to ~3000 m a−1at Seller Glacier, former Wordie Ice Shelf tributary. Variations in iceberg melt rates and glacier frontal ablation rates are significantly positively correlated around the AP (Spearman'sρ= 0.71,p-value = 0.003). We interpret this correlation as support for previous research suggesting submarine melting of glacier termini exerts control on glacier frontal dynamics around the AP.

Highlights

Many marine-terminating glaciers and ice shelves along the Antarctic Peninsula (AP) have undergone significant thinning and retreat in the last three decades (e.g. Liu and others, 2015; Cook and others, 2016; Rott and others, 2018)
In line with iceberg melt rate estimates for Greenland (Enderlin and others, 2018; Moon and others, 2018), we find that iceberg melt rates generally increase with the draft
To minimize the influence of iceberg size on our interpretation, we focus our analysis on iceberg melt rates estimated as the slope of linear polynomials fit the submerged area and meltwater flux estimates for each observation period (Enderlin and others, 2018), hereafter referred to as the mean melt rate (Table 1)

Summary

Introduction

Many marine-terminating glaciers and ice shelves along the Antarctic Peninsula (AP) have undergone significant thinning and retreat in the last three decades (e.g. Liu and others, 2015; Cook and others, 2016; Rott and others, 2018). On the eastern Antarctic Peninsula (EAP), oceanic warming may have been a factor in preconditioning the Larsen A and B ice shelves to their rapid surface meltwater-driven collapse in 1995 and 2002, respectively (Shepherd and others, 2003; Glasser and Scambos, 2008; McGrath and others, 2012). Taken together, these observations suggest that variations in ocean forcing of glaciers and ice shelves across the AP may strongly influence glacier dynamics in this region

Results

Discussion

Conclusion