The Aftermath of Petermann Glacier Calving Events (2008–2012): Ice Island Size Distributions and Meltwater Dispersal

Abstract

Three large calving events occurred at Petermann Glacier in northwest Greenland between 2008 and 2012 that generated ice islands (large tabular icebergs) that ranged from ~30 to 300 km2 in areal extent. Ice islands are known to deteriorate, via fracture and melt, during their drift through regional water bodies where they pose a potential risk to offshore resource extraction operations and disperse freshwater from the Greenland Ice Sheet. This study presents the first analysis of the deterioration occurring across the flux of ice islands that travel between Nares Strait and the North Atlantic after Petermann Glacier calving events. The evolution of Petermann ice island size distributions was evaluated, and the spatial dispersal of meltwater was quantified, through analyses that utilized the newly developed Canadian Ice Island Drift, Deterioration and Detection Database. Size‐frequency distributions remained relatively consistent, both spatially and temporally, and were well fit by power law models with slopes of approximately −1.7. This suggested that fracture was an important process by which the Petermann ice islands deteriorated, regardless of elapsed time or distance from the glacier. Ice island meltwater fluxes into the Baffin Island and Labrador currents were not large enough to slow down the Atlantic Meridional Overturning Circulation by weakening deep‐water convection in the Labrador Sea. However, augmented meltwater input was calculated within Petermann Fjord (2.0 mSv) and in the vicinity of grounding locations (0.4 mSv). Further research is necessary to better understand how this freshwater alters fjord circulation and influences the composition of local ocean waters.

Spatiotemporal distributions of icebergs in a temperate fjord: Columbia Fjord, Alaska

“…The power-law exponents found in the summer months were very close to −1.5, which has been shown both experimentally and theoretically to be indicative of dominant brittle fragmentation (Ångström, 2006;Spahn et al, 2014). Previous studies examining iceberg size distributions resulting from fragmentation have also calculated power-law exponents close to −1.5 (Bouhier et al, 2018;Crawford et al, 2018;Tournadre et al, 2016). The warmer summer conditions in Columbia Fjord could be responsible for the increased iceberg fragmentation.…”

“…Current fjord circulation models do not take icebergs into account, though icebergs may modify warm, dense waters entering the fjord by enhancing vertical mixing and by extracting heat through iceberg melt (Carroll et al, 2015;Klinck et al, 1981;Mortensen et al, 2018;Motyka et al, 2003;Rignot et al, 2010). Various studies have examined the iceberg calving process (Bahr, 1995;Chapuis and Tetzlaff, 2014;Hughes, 2002;O'Neel et al, 2003;Warren et al, 2001), as well as the transport and evolution of icebergs in the open ocean (Bigg et al, 1997;Dowdeswell and Forsberg, 1992;Gladstone et al, 2001;Kubat et al, 2007), but comparably little is known about iceberg evolution inside the fjords where they originate.…”

A stationary impulse-radar system for autonomous deployment in cold and temperate environments

“…PII-A-1-f was first observed on 10 September 2013 after PII-A-1, the largest fragment persisting after the Petermann Glacier calving event, fractured in Nares Strait (personal communication, L. Desjardins). The ice island followed the common route of previous ice islands sourced from northwest Greenland's floating ice tongues, drifting south through Nares Strait and then being directed through the western sector of Baffin Bay by the southerly Baffin Current (Newell, 1993; Crawford and others, 2016, 2018). The 14 km 2 PII-A-1-f became grounded in October 2014 off the east coast of Baffin Island at ~67 ° 23′ N, 63 ° 18′ W, where it was first accessed in October 2015 (Fig.…”

“…Petermann Ice Island (PII)-A-1-f was a fragment of the ~136 km 2 tabular iceberg that calved from the Petermann Glacier in northwest Greenland (80 ° 45′ N, 60 ° 45′ W, Fig. 4a) in July 2012 (Crawford and others, 2018) with a reported average thickness of 182 ± 16 m (Münchow and others, 2014). PII-A-1-f was first observed on 10 September 2013 after PII-A-1, the largest fragment persisting after the Petermann Glacier calving event, fractured in Nares Strait (personal communication, L. Desjardins).…”

Significant contribution of small icebergs to the freshwater budget in Greenland fjords

“…With the increase of Arctic temperatures and the decline in perennial sea ice coverage, a larger region of the Arctic will be open to marine transportation. Therefore, it is crucial to accurately identify both small and large icebergs in Greenlandic fjords and the North Atlantic ocean, as well as investigating their trajectories 18 – 20 with high spatial and temporal resolution.…”