Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica
<p>Ice melting beneath Antarctic ice shelves is caused by heat transfer through the ice-shelf–ocean boundary layer (IOBL). However, our understanding of the fluid dynamics and thermohaline physics of the IOBL flow is poor. In this study, we utilize a large-eddy simulation (LES) model to invest...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-09-01
|
| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/16/3451/2022/tc-16-3451-2022.pdf |
| _version_ | 1818000856450072576 |
|---|---|
| author | J. S. Na T. Kim E. K. Jin S.-T. Yoon W. S. Lee S. Yun J. Lee |
| author_facet | J. S. Na T. Kim E. K. Jin S.-T. Yoon W. S. Lee S. Yun J. Lee |
| author_sort | J. S. Na |
| collection | DOAJ |
| description | <p>Ice melting beneath Antarctic ice shelves is caused by
heat transfer through the ice-shelf–ocean boundary layer (IOBL). However,
our understanding of the fluid dynamics and thermohaline physics of the IOBL
flow is poor. In this study, we utilize a large-eddy simulation (LES) model
to investigate ocean dynamics and the role of turbulence within the IOBL
flow near the ice front. To simulate the varying turbulence intensities, we
imposed different theoretical profiles of the velocity. Far-field ocean
conditions for the melting at the ice-shelf base and freezing at the sea
surface were derived based on in situ observations of temperature and salinity near
the ice front of the Nansen Ice Shelf. In terms of overturning features near
the ice front, we validated the LES simulation results by comparing them
with the in situ observational data. In the comparison of the velocity profiles to
shipborne lowered acoustic Doppler current
profiler (LADCP) data, the LES-derived strength of the overturning cells is
similar to that obtained from the observational data. Moreover, the vertical
distribution of the simulated temperature and salinity, which were mainly
determined by the positively buoyant meltwater and sea-ice formation, was
also comparable to that of the observations. We conclude that the IOBL flow
near the ice front and its contribution to the ocean dynamics can be
realistically resolved using our proposed method. Based on validated 3D-LES
results, we revealed that the main forces of ocean dynamics near the ice
front are driven by positively buoyant meltwater, concentrated salinity at
the sea surface, and outflowing momentum of the sub-ice-shelf plume. Moreover,
in the strong-turbulence case, distinct features such as a higher basal melt
rate (0.153 m yr<span class="inline-formula"><sup>−1</sup></span>), weak upwelling of the positively buoyant ice-shelf
water, and a higher sea-ice formation were observed, suggesting a relatively
high speed current within the IOBL because of highly turbulent mixing. The
findings of this study will contribute toward a deeper understanding of the
complex IOBL-flow physics and its impact on the ocean dynamics near the ice
front.</p> |
| first_indexed | 2024-04-14T03:27:12Z |
| format | Article |
| id | doaj.art-6a72ade5b7b744918e6b95aad5df6716 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-04-14T03:27:12Z |
| publishDate | 2022-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-6a72ade5b7b744918e6b95aad5df67162022-12-22T02:15:08ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242022-09-01163451346810.5194/tc-16-3451-2022Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, AntarcticaJ. S. Na0T. Kim1E. K. Jin2S.-T. Yoon3W. S. Lee4S. Yun5J. Lee6Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, South KoreaDepartment of Earth and Marine Science, Jeju National University, Jeju, 63243, South Korea Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, South KoreaSchool of Earth System Sciences, Kyungpook National University, Daegu, 41566, South Korea Division of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, South KoreaDivision of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, South KoreaDivision of Glacial Environment Research, Korea Polar Research Institute, Incheon, 21990, South Korea<p>Ice melting beneath Antarctic ice shelves is caused by heat transfer through the ice-shelf–ocean boundary layer (IOBL). However, our understanding of the fluid dynamics and thermohaline physics of the IOBL flow is poor. In this study, we utilize a large-eddy simulation (LES) model to investigate ocean dynamics and the role of turbulence within the IOBL flow near the ice front. To simulate the varying turbulence intensities, we imposed different theoretical profiles of the velocity. Far-field ocean conditions for the melting at the ice-shelf base and freezing at the sea surface were derived based on in situ observations of temperature and salinity near the ice front of the Nansen Ice Shelf. In terms of overturning features near the ice front, we validated the LES simulation results by comparing them with the in situ observational data. In the comparison of the velocity profiles to shipborne lowered acoustic Doppler current profiler (LADCP) data, the LES-derived strength of the overturning cells is similar to that obtained from the observational data. Moreover, the vertical distribution of the simulated temperature and salinity, which were mainly determined by the positively buoyant meltwater and sea-ice formation, was also comparable to that of the observations. We conclude that the IOBL flow near the ice front and its contribution to the ocean dynamics can be realistically resolved using our proposed method. Based on validated 3D-LES results, we revealed that the main forces of ocean dynamics near the ice front are driven by positively buoyant meltwater, concentrated salinity at the sea surface, and outflowing momentum of the sub-ice-shelf plume. Moreover, in the strong-turbulence case, distinct features such as a higher basal melt rate (0.153 m yr<span class="inline-formula"><sup>−1</sup></span>), weak upwelling of the positively buoyant ice-shelf water, and a higher sea-ice formation were observed, suggesting a relatively high speed current within the IOBL because of highly turbulent mixing. The findings of this study will contribute toward a deeper understanding of the complex IOBL-flow physics and its impact on the ocean dynamics near the ice front.</p>https://tc.copernicus.org/articles/16/3451/2022/tc-16-3451-2022.pdf |
| spellingShingle | J. S. Na T. Kim E. K. Jin S.-T. Yoon W. S. Lee S. Yun J. Lee Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica The Cryosphere |
| title | Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica |
| title_full | Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica |
| title_fullStr | Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica |
| title_full_unstemmed | Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica |
| title_short | Large-eddy simulations of the ice-shelf–ocean boundary layer near the ice front of Nansen Ice Shelf, Antarctica |
| title_sort | large eddy simulations of the ice shelf ocean boundary layer near the ice front of nansen ice shelf antarctica |
| url | https://tc.copernicus.org/articles/16/3451/2022/tc-16-3451-2022.pdf |
| work_keys_str_mv | AT jsna largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT tkim largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT ekjin largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT styoon largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT wslee largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT syun largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica AT jlee largeeddysimulationsoftheiceshelfoceanboundarylayerneartheicefrontofnanseniceshelfantarctica |