dc.contributor.author |
Giddy, IS
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|
dc.contributor.author |
Fer, I
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|
dc.contributor.author |
Swart, S
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dc.contributor.author |
Nicholson, Sarah-Anne
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dc.date.accessioned |
2023-10-13T12:09:26Z |
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dc.date.available |
2023-10-13T12:09:26Z |
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dc.date.issued |
2023-05 |
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dc.identifier.citation |
Giddy, I., Fer, I., Swart, S. & Nicholson, S. 2023. Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer. <i>Journal of Physical Oceanography, 53(8).</i> http://hdl.handle.net/10204/13154 |
en_ZA |
dc.identifier.issn |
0022-3670 |
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dc.identifier.issn |
1520-0485 |
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dc.identifier.uri |
https://doi.org/10.1175/JPO-D-22-0259.1
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|
dc.identifier.uri |
http://hdl.handle.net/10204/13154
|
|
dc.description.abstract |
The seasonal warming of Antarctic Winter Water (WW) is a key process that occurs along the path of deep water transformation to intermediate waters. These intermediate waters then enter the upper branch of the circumpolar overturning circulation. Despite its importance, the driving mechanisms that mediate the warming of Antarctic WW remain unknown, and their quantitative evaluation is lacking. Using 38 days of glider measurements of microstructure shear, we characterize the rate of turbulent dissipation and its drivers over a summer season in the northern Weddell Sea. Observed dissipation rates in the surface layer are mainly forced by winds, and explained by the stress scaling (r2=0.84). However, mixing to the base of the mixed layer during strong wind events is suppressed by vertical stratification from sea ice melt. Between the WW layer and the warm and saline circumpolar deep water, a subsurface layer of enhanced dissipation is maintained by double-diffusive convection (DDC). We develop a WW layer temperature budget and show that a warming trend (0.2°C over 28 days) is driven by a convergence of heat flux through mechanically-driven mixing at the base of the mixed layer and DDC at the base of the WW layer. Notably, excluding the contribution from DDC results in an underestimation of WW warming by 23%, highlighting the importance of adequately representing DDC in ocean models. These results further suggest that an increase in storm intensity and frequency during summer could increase the rate of warming of WW with implications for rates of upper ocean water mass transformation. |
en_US |
dc.format |
Fulltext |
en_US |
dc.language.iso |
en |
en_US |
dc.relation.uri |
https://journals.ametsoc.org/view/journals/phoc/aop/JPO-D-22-0259.1/JPO-D-22-0259.1.xml |
en_US |
dc.source |
Journal of Physical Oceanography, 53(8) |
en_US |
dc.subject |
Antarctic Winter Water |
en_US |
dc.subject |
Climate change |
en_US |
dc.subject |
Global warming |
en_US |
dc.subject |
Warming of Antarctic |
en_US |
dc.subject |
Winter Water |
en_US |
dc.title |
Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer |
en_US |
dc.type |
Article |
en_US |
dc.description.pages |
1941-1958 |
en_US |
dc.description.note |
Copyright: 2023 American Meteorological Society. This published article is licensed under the terms of a Creative Commons Attribution 4.0 International (CC BY 4.0) License |
en_US |
dc.description.cluster |
Smart Places |
en_US |
dc.description.impactarea |
Ocean Systems and Climate |
en_US |
dc.identifier.apacitation |
Giddy, I., Fer, I., Swart, S., & Nicholson, S. (2023). Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer. <i>Journal of Physical Oceanography, 53(8)</i>, http://hdl.handle.net/10204/13154 |
en_ZA |
dc.identifier.chicagocitation |
Giddy, IS, I Fer, S Swart, and Sarah-Anne Nicholson "Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer." <i>Journal of Physical Oceanography, 53(8)</i> (2023) http://hdl.handle.net/10204/13154 |
en_ZA |
dc.identifier.vancouvercitation |
Giddy I, Fer I, Swart S, Nicholson S. Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer. Journal of Physical Oceanography, 53(8). 2023; http://hdl.handle.net/10204/13154. |
en_ZA |
dc.identifier.ris |
TY - Article
AU - Giddy, IS
AU - Fer, I
AU - Swart, S
AU - Nicholson, Sarah-Anne
AB - The seasonal warming of Antarctic Winter Water (WW) is a key process that occurs along the path of deep water transformation to intermediate waters. These intermediate waters then enter the upper branch of the circumpolar overturning circulation. Despite its importance, the driving mechanisms that mediate the warming of Antarctic WW remain unknown, and their quantitative evaluation is lacking. Using 38 days of glider measurements of microstructure shear, we characterize the rate of turbulent dissipation and its drivers over a summer season in the northern Weddell Sea. Observed dissipation rates in the surface layer are mainly forced by winds, and explained by the stress scaling (r2=0.84). However, mixing to the base of the mixed layer during strong wind events is suppressed by vertical stratification from sea ice melt. Between the WW layer and the warm and saline circumpolar deep water, a subsurface layer of enhanced dissipation is maintained by double-diffusive convection (DDC). We develop a WW layer temperature budget and show that a warming trend (0.2°C over 28 days) is driven by a convergence of heat flux through mechanically-driven mixing at the base of the mixed layer and DDC at the base of the WW layer. Notably, excluding the contribution from DDC results in an underestimation of WW warming by 23%, highlighting the importance of adequately representing DDC in ocean models. These results further suggest that an increase in storm intensity and frequency during summer could increase the rate of warming of WW with implications for rates of upper ocean water mass transformation.
DA - 2023-05
DB - ResearchSpace
DP - CSIR
J1 - Journal of Physical Oceanography, 53(8)
KW - Antarctic Winter Water
KW - Climate change
KW - Global warming
KW - Warming of Antarctic
KW - Winter Water
LK - https://researchspace.csir.co.za
PY - 2023
SM - 0022-3670
SM - 1520-0485
T1 - Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer
TI - Vertical convergence of turbulent and double-diffusive heat flux drives warming and erosion of Antarctic Winter Water in summer
UR - http://hdl.handle.net/10204/13154
ER -
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en_ZA |
dc.identifier.worklist |
26848 |
en_US |