Analysis of Antarctic Peninsula Glacier Frontal Ablation Rates with Respect to Iceberg Melt-Inferred Variability in Ocean Conditions

Marine-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−1 at Edgeworth and Blanchard glaciers to ~3000 m a−1 at 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\u27s ρ = 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

Investigating connections between Iceberg Melt Rates and Glacier Dynamics on the Antarctic Peninsula

Over the past several decades marine-terminating glaciers on the Antarctic Peninsula have retreated, accelerated, and thinned in response to changing climate. Although ocean warming has been implicated as a trigger for these rapid changes in glacier dynamics, there are few ocean observations near inaccessible glacier termini that can be used to assess the role of ocean warming as a control on glacier dynamics in this region. Here we use iceberg melt rates to infer variations in ocean conditions near glacier termini. We map patterns in iceberg melt rates for two study sites on the eastern and five sites on the western Antarctic Peninsula through differencing of high-resolution digital elevation models (DEMs) for at least one time period from 2013-2018, for 14 different observation periods overall. Iceberg melt rates are spatially variable with the highest melt rates (mean = 7.49 cm d-1) at Widdowson Glacier, in the west, and the lowest melt rates (mean = 0.10 cm d-1) at Crane Glacier, in the east. We compare these data to satellite remotely-sensed estimates of glacier frontal ablation (i.e., submarine melting plus calving) from 2014-2018 to investigate if patterns in iceberg melt rates can be used as a proxy for variations in ocean forcing of glacier termini. We find that mean iceberg melt rates generally follow variations in regional ocean temperatures and have a positive relationship with glacier frontal ablation at our study sites. The observed correlation between glacier frontal ablation and iceberg melt rates provide additional support for the hypothesis that glacier dynamics along the Antarctic Peninsula are strongly controlled by ocean conditions. We recommend that remotely-sensed iceberg melt rates continue to be used as proxy for ocean conditions in remote areas where in situ observations proximal to glacier termini are limited