Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland

Mike J.  Bentley; James A.  Smith; Stewart S.R.  Jamieson; Margaret R.  Lindeman; Brice Rea; Angelika  Humbert; Timothy P. Lane; Christopher M.  Darvill; Jeremy M.  Lloyd; Fiamma  Straneo; Veit Helm; David H. Roberts

doi:10.5194/tc-17-1821-2023

Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland

Mike J. Bentley^* (Corresponding Author), James A. Smith, Stewart S.R. Jamieson, Margaret R. Lindeman, Brice Rea, Angelika Humbert, Timothy P. Lane, Christopher M. Darvill, Jeremy M. Lloyd, Fiamma Straneo, Veit Helm, David H. Roberts

^*Corresponding author for this work

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Abstract

The North-East Greenland Ice Stream has recently seen significant change to its floating margins, and has been identified as vulnerable to future climate warming. Inflow of warm Atlantic Intermediate Water (AIW) from the continental shelf has been observed in the vicinity of the Nioghalvfjerdsfjorden (79N) Glacier calving front, but AIW penetration deep into the ice shelf cavity has not been observed directly. Here, we report temperature and salinity measurements from profiles in an epishelf lake, which provide the first direct evidence of AIW proximal to the grounding line of 79N Glacier, over 50 km from the calving front. We also report evidence for partial un-grounding of the margin of 79N taking place at the western end of the epishelf lake. Comparison of our measurements to those close to the calving front shows that AIW transits the cavity to reach the grounding line within a few months. The observations provide support for modelling studies that infer AIW-driven basal melt proximal to the grounding line and demonstrate that offshore oceanographic changes can be rapidly transmitted throughout the sub-ice shelf cavity, with implications for near-future stability of the ice stream.

Original language	English
Pages (from-to)	1821–1837
Number of pages	17
Journal	The Cryosphere
Volume	17
Issue number	5
Early online date	5 May 2023
DOIs	https://doi.org/10.5194/tc-17-1821-2023
Publication status	Published - 5 May 2023

Bibliographical note

Acknowledgements
This work was carried out as part of UK NERC Grant, NE/N011228/1 ‘Greenland in a warmer climate: What controls the advance & retreat of the Northeast Greenland Ice Stream’. We thank the Alfred Wegner Institute, in particular
Hicham Rafiq, for their significant logistic support through the iGRIFF project to the work reported here. The airborne data were acquired as part of the campaign RESURV79 conducted by Polar 6. We also thank Jorgen Skafte (Villum
Research Station), Nordland Air, Air Greenland, Joint Arctic Command (Station Nord) and Nanu-Travel (in particular Isak and Ooni) for their role in supporting the fieldwork at Blåsø. Naalakkersuisut, Government of Greenland, provided
Scientific Survey (VU-00121) and Export (046/2017) licences for this work. We also acknowledge help from the Danmarks Meteorologiske Institut for supplying tidal data, and the support of the Department of Geography, Durham University. Chris Orton (Durham Geography) made Figure 6d-f. Comments from Derek Mueller, Jérémie Bonneau and an anonymous reviewer helped strengthen and clarify the paper.

Keywords

NE/N011228/1

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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Cite this

Bentley, M. J., Smith, J. A., Jamieson, S. S. R., Lindeman, M. R., Rea, B., Humbert, A., Lane, T. P., Darvill, C. M., Lloyd, J. M., Straneo, F., Helm, V., & Roberts, D. H. (2023). Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland. The Cryosphere, 17(5), 1821–1837. https://doi.org/10.5194/tc-17-1821-2023

Bentley, MJ, Smith, JA, Jamieson, SSR, Lindeman, MR, Rea, B, Humbert, A, Lane, TP, Darvill, CM, Lloyd, JM, Straneo, F, Helm, V & Roberts, DH 2023, 'Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland', The Cryosphere, vol. 17, no. 5, pp. 1821–1837. https://doi.org/10.5194/tc-17-1821-2023

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title = "Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland",

abstract = "The North-East Greenland Ice Stream has recently seen significant change to its floating margins, and has been identified as vulnerable to future climate warming. Inflow of warm Atlantic Intermediate Water (AIW) from the continental shelf has been observed in the vicinity of the Nioghalvfjerdsfjorden (79N) Glacier calving front, but AIW penetration deep into the ice shelf cavity has not been observed directly. Here, we report temperature and salinity measurements from profiles in an epishelf lake, which provide the first direct evidence of AIW proximal to the grounding line of 79N Glacier, over 50 km from the calving front. We also report evidence for partial un-grounding of the margin of 79N taking place at the western end of the epishelf lake. Comparison of our measurements to those close to the calving front shows that AIW transits the cavity to reach the grounding line within a few months. The observations provide support for modelling studies that infer AIW-driven basal melt proximal to the grounding line and demonstrate that offshore oceanographic changes can be rapidly transmitted throughout the sub-ice shelf cavity, with implications for near-future stability of the ice stream.",

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author = "Bentley, {Mike J.} and Smith, {James A.} and Jamieson, {Stewart S.R.} and Lindeman, {Margaret R.} and Brice Rea and Angelika Humbert and Lane, {Timothy P.} and Darvill, {Christopher M.} and Lloyd, {Jeremy M.} and Fiamma Straneo and Veit Helm and Roberts, {David H.}",

note = "Acknowledgements This work was carried out as part of UK NERC Grant, NE/N011228/1 {\textquoteleft}Greenland in a warmer climate: What controls the advance & retreat of the Northeast Greenland Ice Stream{\textquoteright}. We thank the Alfred Wegner Institute, in particular Hicham Rafiq, for their significant logistic support through the iGRIFF project to the work reported here. The airborne data were acquired as part of the campaign RESURV79 conducted by Polar 6. We also thank Jorgen Skafte (Villum Research Station), Nordland Air, Air Greenland, Joint Arctic Command (Station Nord) and Nanu-Travel (in particular Isak and Ooni) for their role in supporting the fieldwork at Bl{\aa}s{\o}. Naalakkersuisut, Government of Greenland, provided Scientific Survey (VU-00121) and Export (046/2017) licences for this work. We also acknowledge help from the Danmarks Meteorologiske Institut for supplying tidal data, and the support of the Department of Geography, Durham University. Chris Orton (Durham Geography) made Figure 6d-f. Comments from Derek Mueller, J{\'e}r{\'e}mie Bonneau and an anonymous reviewer helped strengthen and clarify the paper.",

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AU - Bentley, Mike J.

AU - Smith, James A.

AU - Jamieson, Stewart S.R.

AU - Lindeman, Margaret R.

AU - Rea, Brice

AU - Humbert, Angelika

AU - Lane, Timothy P.

AU - Darvill, Christopher M.

AU - Lloyd, Jeremy M.

AU - Straneo, Fiamma

AU - Helm, Veit

AU - Roberts, David H.

N1 - Acknowledgements This work was carried out as part of UK NERC Grant, NE/N011228/1 ‘Greenland in a warmer climate: What controls the advance & retreat of the Northeast Greenland Ice Stream’. We thank the Alfred Wegner Institute, in particular Hicham Rafiq, for their significant logistic support through the iGRIFF project to the work reported here. The airborne data were acquired as part of the campaign RESURV79 conducted by Polar 6. We also thank Jorgen Skafte (Villum Research Station), Nordland Air, Air Greenland, Joint Arctic Command (Station Nord) and Nanu-Travel (in particular Isak and Ooni) for their role in supporting the fieldwork at Blåsø. Naalakkersuisut, Government of Greenland, provided Scientific Survey (VU-00121) and Export (046/2017) licences for this work. We also acknowledge help from the Danmarks Meteorologiske Institut for supplying tidal data, and the support of the Department of Geography, Durham University. Chris Orton (Durham Geography) made Figure 6d-f. Comments from Derek Mueller, Jérémie Bonneau and an anonymous reviewer helped strengthen and clarify the paper.

PY - 2023/5/5

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N2 - The North-East Greenland Ice Stream has recently seen significant change to its floating margins, and has been identified as vulnerable to future climate warming. Inflow of warm Atlantic Intermediate Water (AIW) from the continental shelf has been observed in the vicinity of the Nioghalvfjerdsfjorden (79N) Glacier calving front, but AIW penetration deep into the ice shelf cavity has not been observed directly. Here, we report temperature and salinity measurements from profiles in an epishelf lake, which provide the first direct evidence of AIW proximal to the grounding line of 79N Glacier, over 50 km from the calving front. We also report evidence for partial un-grounding of the margin of 79N taking place at the western end of the epishelf lake. Comparison of our measurements to those close to the calving front shows that AIW transits the cavity to reach the grounding line within a few months. The observations provide support for modelling studies that infer AIW-driven basal melt proximal to the grounding line and demonstrate that offshore oceanographic changes can be rapidly transmitted throughout the sub-ice shelf cavity, with implications for near-future stability of the ice stream.

AB - The North-East Greenland Ice Stream has recently seen significant change to its floating margins, and has been identified as vulnerable to future climate warming. Inflow of warm Atlantic Intermediate Water (AIW) from the continental shelf has been observed in the vicinity of the Nioghalvfjerdsfjorden (79N) Glacier calving front, but AIW penetration deep into the ice shelf cavity has not been observed directly. Here, we report temperature and salinity measurements from profiles in an epishelf lake, which provide the first direct evidence of AIW proximal to the grounding line of 79N Glacier, over 50 km from the calving front. We also report evidence for partial un-grounding of the margin of 79N taking place at the western end of the epishelf lake. Comparison of our measurements to those close to the calving front shows that AIW transits the cavity to reach the grounding line within a few months. The observations provide support for modelling studies that infer AIW-driven basal melt proximal to the grounding line and demonstrate that offshore oceanographic changes can be rapidly transmitted throughout the sub-ice shelf cavity, with implications for near-future stability of the ice stream.

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DO - 10.5194/tc-17-1821-2023

M3 - Article

SN - 1994-0416

VL - 17

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EP - 1837

JO - The Cryosphere

JF - The Cryosphere

IS - 5

ER -

Direct measurement of warm Atlantic Intermediate Water close to the grounding line of Nioghalvfjerdsfjorden (79°N) Glacier, Northeast Greenland

Abstract

Bibliographical note

Keywords

UN SDGs

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