Meltwater pathways from marine terminating glaciers of the Greenland ice sheet

Gillard, Laura C.; Hu, Xianmin; Myers, Paul G.; Bamber, Jonathan

doi:10.1002/2016gl070969

Cited by 77 publications

(83 citation statements)

References 53 publications

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“…Several regions where freshwater deviates into the interior have been identified downstream of our array in observations: the tip of CF (Holliday et al, ) and the unstable West Greenland Current (Bracco et al, ; Myers et al, ; Rykova et al, ; Schmidt & Send, ). Furthermore, several recent modeling studies have found that freshwater originating east of Greenland is more likely to enter the Labrador Sea than freshwater originating west of Greenland (Gillard et al, ; Luo et al, ; Marson et al, ; Tesdal et al, ; Wang et al, ). In particular, water over the slope east of Greenland is more likely to enter the Labrador Sea than water originating on the shelf (Schulze Chretien & Frajka‐Williams, ).…”

Section: Discussionmentioning

confidence: 99%

“…Freshwater is a key player in the formation of globally significant water masses in the subpolar gyre (Manabe & Stouffer, 1995). In particular, the freshwater flowing east of Greenland, which includes Arctic freshwater and sea ice, as well as Greenland melt and icebergs, has been shown to be the primary source of freshwater for the subpolar gyre interior in recent modeling studies (Gillard et al, 2016;Luo et al, 2016;Marson et al, 2018;Schulze Chretien & Frajka-Williams, 2018;Tesdal et al, 2018;Wang et al, 2018). Freshwater export from the Arctic and Greenland is expected to increase (Alley et al, 2005;Wang & Overland, 2009), with potential consequences for the formation of intermediate North Atlantic Deep Waters and global climate.…”

Section: Introductionmentioning

confidence: 99%

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Seasonality of Freshwater in the East Greenland Current System From 2014 to 2016

et al. 2018

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The initial 2 years of Overturning in the Subpolar North Atlantic Program mooring data (2014–2016) provide the first glimpse into the seasonality of freshwater in the complete East Greenland Current system. Using a set of eight moorings southeast of Greenland at 60∘ N, we find two distinct, persistent velocity cores on the shelf and slope. These are the East Greenland Coastal Current, which carries cold, fresh water from the Arctic and Greenland along the shelf, and the East Greenland/Irminger Current over the slope, which is a combination of cold, fresh waters and warm, salty waters of Atlantic origin. Together, these currents carry 70% of the freshwater transport across the subpolar North Atlantic east of Greenland. The freshwater transport referenced to a salinity of 34.9 is approximately equipartitioned between the coastal current (East Greenland Coastal Current) and the fresh portion of the slope current (East Greenland Current), which carry 42 ± 6 and 32 ± 6 mSv, respectively. The coastal and slope current freshwater transports have staggered seasonality during the observed period, peaking in December and March, respectively, suggesting that summer surveys have underestimated freshwater transport in this region. We find that the continental slope is freshest in the winter, when surface cooling mixes freshwater off the shelf. This previously unmeasured freshwater over the slope is likely to enter the Labrador Sea downstream, where it can impact deep convection.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seasonality of Freshwater in the East Greenland Current System From 2014 to 2016

et al. 2018

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“…The strength of the Atlantic Meridional Overturning Circulation (AMOC) is of concern when considering the increasing freshwater flux from the Greenland Ice Sheet and potential consequences to global ocean circulation and energy transfers (Bamber et al, 2012;Böning et al, 2016;Gillard et al, 2016;Yang et al, 2016). In their modeling studies, Gillard et al (2016), Marson et al (2018), and Wagner and Eisenman (2017) note that direct meltwater input from the Greenland Ice Sheet or via iceberg deterioration could affect deep-water convection in the North Atlantic and potentially lead to a slowdown of the AMOC. However, a sustained freshwater flux anomaly of at least 7 mSv in the North Atlantic is thought to be necessary to substantially slowdown the AMOC (Brunnabrend et al, 2015;Yang et al, 2016).…”

Section: Meltwater Dispersalmentioning

confidence: 99%

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

et al. 2018

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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.

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“…Many of the earlier studies have used an idealized FWF, typically averaged zonally and sometimes with unrealistically large flux anomalies (Gerdes et al, 2006;Hu et al, 2009;Jungclaus et al, 2006). More recently, experiments have used an observational and model-based estimate of FWF from the GrIS to investigate its potential role on the hydrography of the SNA and influence on the Atlantic Meridional Overturning Circulation (AMOC) (Boning et al, 2016;Dukhovskoy et al, 2016;Gillard et al, 2016;Marsh et al, 2010;Yang et al, 2016). From these analyses, it has been suggested, for example, that changes to deep Labrador Sea Water are linked to enhanced FWF from the GrIS (Yang et al, 2016) and that, if the FWF trend continues, it could play an important role in modulating the strength of the AMOC (Boning et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Land Ice Freshwater Budget of the Arctic and North Atlantic Oceans: 1. Data, Methods, and Results

et al. 2018

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The freshwater budget of the Arctic and sub‐polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea ice and enhanced melting of Arctic land ice. Since the mid‐1990s this latter component has experienced a pronounced increase. We use a combination of satellite observations of glacier flow speed and regional climate modeling to reconstruct the land ice freshwater flux from the Greenland ice sheet and Arctic glaciers and ice caps for the period 1958–2016. The cumulative freshwater flux anomaly exceeded 6,300 ± 316 km 3 by 2016. This is roughly twice the estimate of a previous analysis that did not include glaciers and ice caps outside of Greenland and which extended only to 2010. From 2010 onward, the total freshwater flux is about 1,300 km 3 /yr, equivalent to 0.04 Sv, which is roughly 40% of the estimated total runoff to the Arctic for the same time period. Not all of this flux will reach areas of deep convection or Arctic and Sub‐Arctic seas. We note, however, that the largest freshwater flux anomalies, grouped by ocean basin, are located in Baffin Bay and Davis Strait. The land ice freshwater flux displays a strong seasonal cycle with summer time values typically around five times larger than the annual mean. This will be important for understanding the impact of these fluxes on fjord circulation, stratification, and the biogeochemistry of, and nutrient delivery to, coastal waters.

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Meltwater pathways from marine terminating glaciers of the Greenland ice sheet

Cited by 77 publications

References 53 publications

Seasonality of Freshwater in the East Greenland Current System From 2014 to 2016

Seasonality of Freshwater in the East Greenland Current System From 2014 to 2016

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

Land Ice Freshwater Budget of the Arctic and North Atlantic Oceans: 1. Data, Methods, and Results

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