Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12
Abstract The Arctic seasonal halocline impacts the exchange of heat, energy, and nutrients between the surface and the deeper ocean, and it is changing in response to Arctic sea ice melt over the past several decades. Here, we assess seasonal halocline formation in 1975 and 2006–12 by comparing dail...
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2022
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ftcdlib:oai:escholarship.org:ark:/13030/qt00z3g180 2023-05-15T14:52:02+02:00 Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 Rosenblum, Erica Stroeve, Julienne Gille, Sarah T Lique, Camille Fajber, Robert Tremblay, L Bruno Galley, Ryan Loureiro, Thiago Barber, David G Lukovich, Jennifer V 1383 - 1396 2022-07-01 application/pdf https://escholarship.org/uc/item/00z3g180 unknown eScholarship, University of California qt00z3g180 https://escholarship.org/uc/item/00z3g180 public Journal of Physical Oceanography, vol 52, iss 7 Climate Action Life Below Water Ocean Arctic Ocean dynamics Mixed layer Seasonal variability Multidecadal variability Oceanography Maritime Engineering article 2022 ftcdlib 2023-02-13T18:45:25Z Abstract The Arctic seasonal halocline impacts the exchange of heat, energy, and nutrients between the surface and the deeper ocean, and it is changing in response to Arctic sea ice melt over the past several decades. Here, we assess seasonal halocline formation in 1975 and 2006–12 by comparing daily, May–September, salinity profiles collected in the Canada Basin under sea ice. We evaluate differences between the two time periods using a one-dimensional (1D) bulk model to quantify differences in freshwater input and vertical mixing. The 1D metrics indicate that two separate factors contribute similarly to stronger stratification in 2006–12 relative to 1975: 1) larger surface freshwater input and 2) less vertical mixing of that freshwater. The larger freshwater input is mainly important in August–September, consistent with a longer melt season in recent years. The reduced vertical mixing is mainly important from June until mid-August, when similar levels of freshwater input in 1975 and 2006–12 are mixed over a different depth range, resulting in different stratification. These results imply that decadal changes to ice–ocean dynamics, in addition to freshwater input, significantly contribute to the stronger seasonal stratification in 2006–12 relative to 1975. These findings highlight the need for near-surface process studies to elucidate the impact of lateral processes and ice–ocean momentum exchange on vertical mixing. Moreover, the results may provide insight for improving the representation of decadal changes to Arctic upper-ocean stratification in climate models that do not capture decadal changes to vertical mixing. Article in Journal/Newspaper Arctic Arctic Ocean canada basin Sea ice University of California: eScholarship Arctic Arctic Ocean Canada |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Life Below Water Ocean Arctic Ocean dynamics Mixed layer Seasonal variability Multidecadal variability Oceanography Maritime Engineering |
spellingShingle |
Climate Action Life Below Water Ocean Arctic Ocean dynamics Mixed layer Seasonal variability Multidecadal variability Oceanography Maritime Engineering Rosenblum, Erica Stroeve, Julienne Gille, Sarah T Lique, Camille Fajber, Robert Tremblay, L Bruno Galley, Ryan Loureiro, Thiago Barber, David G Lukovich, Jennifer V Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
topic_facet |
Climate Action Life Below Water Ocean Arctic Ocean dynamics Mixed layer Seasonal variability Multidecadal variability Oceanography Maritime Engineering |
description |
Abstract The Arctic seasonal halocline impacts the exchange of heat, energy, and nutrients between the surface and the deeper ocean, and it is changing in response to Arctic sea ice melt over the past several decades. Here, we assess seasonal halocline formation in 1975 and 2006–12 by comparing daily, May–September, salinity profiles collected in the Canada Basin under sea ice. We evaluate differences between the two time periods using a one-dimensional (1D) bulk model to quantify differences in freshwater input and vertical mixing. The 1D metrics indicate that two separate factors contribute similarly to stronger stratification in 2006–12 relative to 1975: 1) larger surface freshwater input and 2) less vertical mixing of that freshwater. The larger freshwater input is mainly important in August–September, consistent with a longer melt season in recent years. The reduced vertical mixing is mainly important from June until mid-August, when similar levels of freshwater input in 1975 and 2006–12 are mixed over a different depth range, resulting in different stratification. These results imply that decadal changes to ice–ocean dynamics, in addition to freshwater input, significantly contribute to the stronger seasonal stratification in 2006–12 relative to 1975. These findings highlight the need for near-surface process studies to elucidate the impact of lateral processes and ice–ocean momentum exchange on vertical mixing. Moreover, the results may provide insight for improving the representation of decadal changes to Arctic upper-ocean stratification in climate models that do not capture decadal changes to vertical mixing. |
format |
Article in Journal/Newspaper |
author |
Rosenblum, Erica Stroeve, Julienne Gille, Sarah T Lique, Camille Fajber, Robert Tremblay, L Bruno Galley, Ryan Loureiro, Thiago Barber, David G Lukovich, Jennifer V |
author_facet |
Rosenblum, Erica Stroeve, Julienne Gille, Sarah T Lique, Camille Fajber, Robert Tremblay, L Bruno Galley, Ryan Loureiro, Thiago Barber, David G Lukovich, Jennifer V |
author_sort |
Rosenblum, Erica |
title |
Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
title_short |
Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
title_full |
Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
title_fullStr |
Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
title_full_unstemmed |
Freshwater Input and Vertical Mixing in the Canada Basin’s Seasonal Halocline: 1975 versus 2006–12 |
title_sort |
freshwater input and vertical mixing in the canada basin’s seasonal halocline: 1975 versus 2006–12 |
publisher |
eScholarship, University of California |
publishDate |
2022 |
url |
https://escholarship.org/uc/item/00z3g180 |
op_coverage |
1383 - 1396 |
geographic |
Arctic Arctic Ocean Canada |
geographic_facet |
Arctic Arctic Ocean Canada |
genre |
Arctic Arctic Ocean canada basin Sea ice |
genre_facet |
Arctic Arctic Ocean canada basin Sea ice |
op_source |
Journal of Physical Oceanography, vol 52, iss 7 |
op_relation |
qt00z3g180 https://escholarship.org/uc/item/00z3g180 |
op_rights |
public |
_version_ |
1766323163539439616 |