Large ice loss variability at Nioghalvfjerdsfjorden Glacier, Northeast-Greenland

Mayer, Christoph; Schaffer, Janin; Hattermann, Tore; Floricioiu, Dana; Krieger, Lukas; Dodd, Paul A.; Kanzow, Torsten; Licciulli, Carlo; Schannwell, Clemens

doi:10.1038/s41467-018-05180-x

Cited by 58 publications

(82 citation statements)

References 44 publications

(57 reference statements)

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“…The mean melt rates calculated using Eq. 9 match the model results well above -1.3 • C. Note that for a stable ice tongue (m sub = 4.2 m yr −1 ), equation 9 yields a AW temperature of approximately -0.8 • C. However, observations in the last decades show significantly warmer temperatures (Mayer et al, 2018;Schaffer et al, 2017;Wilson and Straneo, 2015;Mayer et al, 2000) m mean = 0.677…”

Section: Ice Shelf Water Plume -Ocean Forcing Sensitivitysupporting

confidence: 63%

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Sensitivity of submarine melting on North East Greenland towards ocean forcing

Anhaus

Smedsrud

Årthun

et al. 2019

Preprint

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Abstract. The Nioghalvfjerdsbræ (79NG) is a floating ice tongue on Northeast Greenland draining a large part of the Greenland Ice Sheet. A CTD profile from a rift on the ice tongue close to the northern front shows that Atlantic Water (AW) is present in the cavity below, with maximum temperature of approximately 1 °C at 610 m depth. The AW present in the cavity thus has the potential to drive submarine melting along the ice base. Here, we simulate melt rates from the 79NG with a 1D numerical Ice Shelf Water (ISW) plume model. A meltwater plume is initiated at the grounding line depth (600 m) and rises along the ice base as a result of buoyancy contrast to the underlying AW. Ice melts as the plume entrains the warm AW. Maximum simulated melt rates are 50–76 m yr−1 within 10 km of the grounding line. Within a zone of rapid decay between 10 km and 20 km melt rates drop to roughly 6 m yr−1. Further downstream, melt rates are between 15 m yr−1 and 6 m yr−1. The melt-rate sensitivity to variations in AW temperatures is assessed by forcing the model with AW temperatures between 0.1–1.4 °C, as identified from the ECCOv4 ocean state estimate. The melt rates increase linearly with rising AW temperature, ranging from 10 m yr−1 to 21 m yr−1 along the centerline. The corresponding freshwater flux ranges between 11 km3 yr−1 (0.4 mSv) and 30 km3 yr−1 (1.0 mSv), which is 5 % and 12 % of the total freshwater flux from the Greenland Ice Sheet since 1995, respectively. Our results improve the understanding of processes driving submarine melting of marine-terminating glaciers around Greenland, and its sensitivity to changing ocean conditions.

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Section: Ice Shelf Water Plume -Ocean Forcing Sensitivitysupporting

confidence: 63%

“…10.2 ± 0.59 km 3 yr −1 . Further, Mayer et al (2018) found that the 79NG ice tongue will most likely disappear within a few decades based on observations of surface features, ice thickness, and bedrock data.…”

Section: Stability Of the 79ng Ice Tonguementioning

confidence: 99%

Sensitivity of submarine melting on North East Greenland towards ocean forcing

Anhaus

Smedsrud

Årthun

et al. 2019

Preprint

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“…Enhanced stability of 79N has been recently tested under various future warming scenarios by another modelling study (Choi et al, 2017), suggesting that it may be related to the presence of pinning points (such as ice rises) near the calving front. Ice loss from these two marine-terminating glaciers is thought to be partly related to the increasing temperature of North Atlantic waters (Khan et al, 2014;Mouginot et al, 2015), which increases the oceanic heat flux and accelerates the submarine melting (Mayer et al, 2018). This hypothesis is supported by the three-decade-long observed warming in the subpolar North Atlantic (Straneo and Heimbach, 2013, and references therein).…”

Section: Introductionmentioning

confidence: 97%

“…In less than 15 years the ZI floating tongue has lost 95 % of its size as a result of an enhanced mass loss (Mouginot et al, 2015). Concurrently, since 1999 the 79N ice shelf has lost 30 % of its thickness at the grounding line (Mouginot et al, 2015), contributing to its inland retreat by 2 km (Mayer et al, 2018). However, since 79N is retreating over an upward-sloping bed (Mouginot et al, 2015), it may be less prone than ZI to an unstable retreat.…”

Section: Introductionmentioning

confidence: 99%

Submarine melt as a potential trigger of the North East Greenland Ice Stream margin retreat during Marine Isotope Stage 3

et al. 2019

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The Northeast Greenland Ice Stream (NEGIS) has been suffering a significant ice mass loss during the last decades. This is partly due to increasing oceanic temperatures in the subpolar North Atlantic, which enhance submarine basal melting and mass discharge. This demonstrates the high sensitivity of this region to oceanic changes. In addition, a recent study suggested that the NEGIS grounding line was 20-40 km behind its present-day location for 15 ka during Marine Isotope Stage (MIS) 3. This is in contrast with Greenland temperature records indicating cold atmospheric conditions at that time, expected to favour ice-sheet expansion. To explain this anomalous retreat a combination of atmospheric and external forcings has been invoked. Yet, as the ocean is found to be a primary driver of the ongoing retreat of the NEGIS glaciers, the effect of past oceanic changes in their paleo evolution cannot be ruled out and should be explored in detail. Here we investigate the sensitivity of the NEGIS to the oceanic forcing during the last glacial period using a three-dimensional hybrid ice-sheet-shelf model. We find that a sufficiently high oceanic forcing could account for a NEGIS ice-margin retreat of several tens of kilometres, potentially explaining the recently proposed NEGIS groundingline retreat during Marine Isotope Stage 3.

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“…often named 79°N after its latitudinal position. Until recently, very few studies focused on 79°N glacier and NEGIS as they were thought to contribute little to surface mass loss and instabilities (Khan et al, 2014;Mayer et al, 2018). However, 79°N glacier, with its 80 km long by 20 km wide floating tongue, has retreated by 2-3km between 2009 and 2012, and is now thinning at a rate of 1 m yr -1 (Khan et al, 2014).…”

mentioning

confidence: 99%

High-resolution (1 km) Polar WRF output for 79° N Glacier and the Northeast of Greenland from 2014–2018

Turton¹,

Mölg²,

Collier³

2019

Preprint

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Abstract. The northeast region of Greenland is of growing interest due to changes taking place on the large marine-terminating glaciers which drain the north east Greenland ice stream. Nioghalvfjerdsfjordern, or 79° N glacier, is one of these glaciers that is currently experiencing accelerated thinning, retreat and enhanced surface melt. Understanding both the influence of atmospheric processes on the glacier and the interactions between the atmosphere and the changing surface is crucial for our understanding of present stability and future change. However, relatively few studies have focused on the atmospheric processes in this region, and even fewer have used high-resolution modelling as a tool for these research questions. Here we present a high-resolution (1 km) atmospheric modelling dataset, NEGIS_WRF, for the 79° N and northeast Greenland region from 2014–2018, and an evaluation of the model’s success at representing daily near-surface meteorology compared with two automatic weather station records. The dataset, (Turton et al, 2019b: https://doi.org/10.17605/OSF.IO/53E6Z), is now available for a wide variety of applications ranging from atmospheric dynamics, to input for hydrological and oceanic modelling studies.

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Large ice loss variability at Nioghalvfjerdsfjorden Glacier, Northeast-Greenland

Cited by 58 publications

References 44 publications

Sensitivity of submarine melting on North East Greenland towards ocean forcing

Sensitivity of submarine melting on North East Greenland towards ocean forcing

Submarine melt as a potential trigger of the North East Greenland Ice Stream margin retreat during Marine Isotope Stage 3

High-resolution (1 km) Polar WRF output for 79° N Glacier and the Northeast of Greenland from 2014–2018

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