Articles | Volume 14, issue 4
https://doi.org/10.5194/os-14-801-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-14-801-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Turbulent length scales in a fast-flowing, weakly stratified, strait: Cook Strait, New Zealand
Craig L. Stevens
CORRESPONDING AUTHOR
National Institute of Water and Atmospheric Research, Greta Point,
Wellington, 6021, New Zealand
Department of Physics, University of Auckland, Auckland, New Zealand
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Ocean Sci., 18, 1109–1130, https://doi.org/10.5194/os-18-1109-2022, https://doi.org/10.5194/os-18-1109-2022, 2022
Short summary
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Understanding ocean-driven melting of Antarctic ice shelves is critical for predicting future sea level. However, ocean observations from beneath ice shelves are scarce. Here, we present unique ocean and melting data from the Amery Ice Shelf, East Antarctica. We use our observations to evaluate common methods of representing melting in ocean–climate models (melting
parameterisations) and show that these parameterisations overestimate melting when the ocean is warm and/or currents are weak.
Craig Stevens, Natalie Robinson, Gabby O'Connor, and Brett Grant
The Cryosphere Discuss., https://doi.org/10.5194/tc-2020-249, https://doi.org/10.5194/tc-2020-249, 2020
Revised manuscript not accepted
Short summary
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Along Antarctica's coastal margin melting ice shelves create plumes of very cold sea water. In some circumstances the water is so cold that ice crystals exist in suspension. We present evidence from near the McMurdo Ice Shelf of ice crystals far larger than normal (by an order of magnitude or more). The crystal behaviour is examined by combining measurements of the crystal motion with ocean flow and turbulence data. This helps us make links between ice shelf melting and sea ice formation.
Rebecca A. McPherson, Craig L. Stevens, Joanne M. O'Callaghan, Andrew J. Lucas, and Jonathan D. Nash
Ocean Sci., 16, 799–815, https://doi.org/10.5194/os-16-799-2020, https://doi.org/10.5194/os-16-799-2020, 2020
Short summary
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River plume characteristics (density, velocity, turbulence) are measured in the first several kilometers of a river flow entering a New Zealand fjord. These observations are used to quantify the influence of the main plume dynamics on controlling the behavior and structure of the flow. The mixing of dense, stationary water from below into the fast-flowing plume drove its deceleration. Internal waves were capable of transporting almost 15 % of the total momentum out beyond the plume's boundaries.
Seung-Tae Yoon, Won Sang Lee, Craig Stevens, Stefan Jendersie, SungHyun Nam, Sukyoung Yun, Chung Yeon Hwang, Gwang Il Jang, and Jiyeon Lee
Ocean Sci., 16, 373–388, https://doi.org/10.5194/os-16-373-2020, https://doi.org/10.5194/os-16-373-2020, 2020
Short summary
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We investigated the variability in high-salinity shelf water (HSSW) formation in the Terra Nova Bay polynya using hydrographic data from instrumented moorings and vessel-based profiles. We show that HSSW can be formed in the upper water column of the eastern Terra Nova Bay via polynya activity and convective processes, as well as how the nature of circulation in Terra Nova Bay influences HSSW production. This article also discusses the present results in the context of previous analyses.
Miles G. McPhee, Craig L. Stevens, Inga J. Smith, and Natalie J. Robinson
Ocean Sci., 12, 507–515, https://doi.org/10.5194/os-12-507-2016, https://doi.org/10.5194/os-12-507-2016, 2016
Short summary
Short summary
Measurements of turbulent heat fluxes in tidally modulated flow of supercool seawater under Antarctic land-fast sea ice show that turbulent heat exchange at the ocean–ice boundary is characterized by the product of friction velocity and (negative) water temperature departure from freezing. Also, the conditions cause platelet ice growth to form on the underside of the sea ice which increases the hydraulic roughness (drag) of fast ice compared to ice without platelets.
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Short summary
Mixing in the ocean is highly variable and it is often difficult to measure the more energetic regions. Here we present the first full-depth turbulence profiles from Cook Strait, New Zealand. This 22 km wide channel between the major islands of New Zealand sustains very fast tidally driven flows. The measurements show that large vertical eddies exist, moving water up and down. This will affect stratification, as well as any biology, as it passes through the strait.
Mixing in the ocean is highly variable and it is often difficult to measure the more energetic...