Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland)

Sergei Kirillov, Igor Dmitrenko, Soren Rysgaard, David Babb, Leif Toudal Pedersen, Jens Ehn, Jorgen Bendtsen, David Barber

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Abstract

In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22-24 April, when northerly winds exceeded 15 ms(-1). The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0-40 m) layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of down-welling lasted similar to 4 days. Although current velocities did not exceed 5 cm s(-1), the enhanced circulation during the storm caused cold turbid intrusions at 75-95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at similar to 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus.Our findings provide evidence that shelf-basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.
Original languageEnglish
JournalOcean Science
Volume13
Issue number6
Pages (from-to)947-959
Number of pages13
ISSN1812-0784
DOIs
Publication statusPublished - 2017

Bibliographical note

© Author(s) 2017. This work is distributed under the Creative Commons Attribution 4.0 License.

Cite this

Kirillov, Sergei ; Dmitrenko, Igor ; Rysgaard, Soren ; Babb, David ; Pedersen, Leif Toudal ; Ehn, Jens ; Bendtsen, Jorgen ; Barber, David. / Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland). In: Ocean Science. 2017 ; Vol. 13, No. 6. pp. 947-959.
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abstract = "In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22-24 April, when northerly winds exceeded 15 ms(-1). The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0-40 m) layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of down-welling lasted similar to 4 days. Although current velocities did not exceed 5 cm s(-1), the enhanced circulation during the storm caused cold turbid intrusions at 75-95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at similar to 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus.Our findings provide evidence that shelf-basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.",
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Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland). / Kirillov, Sergei; Dmitrenko, Igor; Rysgaard, Soren; Babb, David; Pedersen, Leif Toudal; Ehn, Jens; Bendtsen, Jorgen; Barber, David.

In: Ocean Science, Vol. 13, No. 6, 2017, p. 947-959.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Storm-induced water dynamics and thermohaline structure at the tidewater Flade Isblink Glacier outlet to theWandel Sea (NE Greenland)

AU - Kirillov, Sergei

AU - Dmitrenko, Igor

AU - Rysgaard, Soren

AU - Babb, David

AU - Pedersen, Leif Toudal

AU - Ehn, Jens

AU - Bendtsen, Jorgen

AU - Barber, David

N1 - © Author(s) 2017. This work is distributed under the Creative Commons Attribution 4.0 License.

PY - 2017

Y1 - 2017

N2 - In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22-24 April, when northerly winds exceeded 15 ms(-1). The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0-40 m) layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of down-welling lasted similar to 4 days. Although current velocities did not exceed 5 cm s(-1), the enhanced circulation during the storm caused cold turbid intrusions at 75-95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at similar to 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus.Our findings provide evidence that shelf-basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.

AB - In April 2015, an ice-tethered conductivity-temperature-depth (CTD) profiler and a down-looking acoustic Doppler current profiler (ADCP) were deployed from the landfast ice near the tidewater glacier terminus of the Flade Isblink Glacier in the Wandel Sea, NE Greenland. The 3-week time series showed that water dynamics and the thermohaline structure were modified considerably during a storm event on 22-24 April, when northerly winds exceeded 15 ms(-1). The storm initiated downwelling-like water dynamics characterized by on-shore water transport in the surface (0-40 m) layer and compensating offshore flow at intermediate depths. After the storm, currents reversed in both layers, and the relaxation phase of down-welling lasted similar to 4 days. Although current velocities did not exceed 5 cm s(-1), the enhanced circulation during the storm caused cold turbid intrusions at 75-95 m depth, which are likely attributable to subglacial water from the Flade Isblink Ice Cap. It was also found that the semidiurnal periodicities in the temperature and salinity time series were associated with the lunar semidiurnal tidal flow. The vertical structure of tidal currents corresponded to the first baroclinic mode of the internal tide with a velocity minimum at similar to 40 m. The tidal ellipses rotate in opposite directions above and below this depth and cause a divergence of tidal flow, which was observed to induce semidiurnal internal waves of about 3 m height at the front of the glacier terminus.Our findings provide evidence that shelf-basin interaction and tidal forcing can potentially modify coastal Wandel Sea waters even though they are isolated from the atmosphere by landfast sea ice almost year-round. The northerly storms over the continental slope cause an enhanced circulation facilitating a release of cold and turbid subglacial water to the shelf. The tidal flow may contribute to the removal of such water from the glacial terminus.

U2 - 10.5194/os-13-947-2017

DO - 10.5194/os-13-947-2017

M3 - Journal article

VL - 13

SP - 947

EP - 959

JO - Ocean Science

JF - Ocean Science

SN - 1812-0784

IS - 6

ER -