Variability of Upper Ocean Heat Balance in the Shikoku Basin during the Ocean Mixed Layer Experiment (OMLET)

2003 ◽  
Vol 59 (5) ◽  
pp. 619-627 ◽  
Author(s):  
Hirotaka Otobe ◽  
Keisuke Taira ◽  
Shoji Kitagawa ◽  
Tomio Asai ◽  
Kimio Hanawa
Keyword(s):  
Mixed Layer ◽  
Heat Balance ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
Shikoku Basin

scholarly journals Energetic Submesoscales Maintain Strong Mixed Layer Stratification during an Autumn Storm

2017 ◽  
Vol 47 (10) ◽  
pp. 2419-2427 ◽  
Author(s):  
Daniel B. Whitt ◽  
John R. Taylor
Keyword(s):  
Mixed Layer ◽  
North Atlantic ◽  
Small Scale ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
Ocean Stratification ◽  
The North ◽  
Large Eddy ◽  
The Mean ◽  
Scale Turbulence

AbstractAtmospheric storms are an important driver of changes in upper-ocean stratification and small-scale (1–100 m) turbulence. Yet, the modifying effects of submesoscale (0.1–10 km) motions in the ocean mixed layer on stratification and small-scale turbulence during a storm are not well understood. Here, large-eddy simulations are used to study the coupled response of submesoscale and small-scale turbulence to the passage of an idealized autumn storm, with a wind stress representative of a storm observed in the North Atlantic above the Porcupine Abyssal Plain. Because of a relatively shallow mixed layer and a strong downfront wind, existing scaling theory predicts that submesoscales should be unable to restratify the mixed layer during the storm. In contrast, the simulations reveal a persistent and strong mean stratification in the mixed layer both during and after the storm. In addition, the mean dissipation rate remains elevated throughout the mixed layer during the storm, despite the strong mean stratification. These results are attributed to strong spatial variability in stratification and small-scale turbulence at the submesoscale and have important implications for sampling and modeling submesoscales and their effects on stratification and turbulence in the upper ocean.

scholarly journals Simulation of More Realistic Upper-Ocean Processes from an OGCM with a New Ocean Mixed Layer Model

2002 ◽  
Vol 32 (5) ◽  
pp. 1284-1307 ◽  
Author(s):  
Yign Noh ◽  
Chan Joo Jang ◽  
Toshio Yamagata ◽  
Peter C. Chu ◽  
Cheol-Ho Kim
Keyword(s):  
Mixed Layer ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
Layer Model ◽  
Mixed Layer Model ◽  
Ocean Processes

scholarly journals A Gas Tension Device with Response Times of Minutes

2006 ◽  
Vol 23 (11) ◽  
pp. 1539-1558 ◽  
Author(s):  
Craig McNeil ◽  
Eric D’Asaro ◽  
Bruce Johnson ◽  
Matthew Horn
Keyword(s):  
Mixed Layer ◽  
Puget Sound ◽  
Pressure Gauge ◽  
Dead Volume ◽  
Upper Ocean ◽  
Dynamical Response ◽  
Depth Range ◽  
Membrane Interface ◽  
Ocean Mixed Layer ◽  
Dissolved Air

Abstract The development and testing of a new, fast response, profiling gas tension device (GTD) that measures total dissolved air pressure is presented. The new GTD equilibrates a sample volume of air using a newly developed (patent pending) tubular silicone polydimethylsiloxane (PDMS) membrane interface. The membrane interface is long, flexible, tubular, and is contained within a seawater-flushed hose. The membrane interface communicates pressure to a precise pressure gauge using low dead-volume stainless steel tubing. The pressure sensor and associated electronics are located remotely from the membrane interface. The new GTD has an operating depth in seawater of 0–300 m. The sensor was integrated onto an upper-ocean mixed layer, neutrally buoyant float, and used in air–sea gas exchange studies. Results of laboratory and pressure tank tests are presented to show response characteristics of the device. A significant hydrostatic response of the instrument was observed over the depth range of 0–9 m, and explained in terms of expulsion (or absorption) of dissolved air from the membrane after it is compressed (or decompressed). This undesirable feature of the device is unavoidable since a large exposed surface area of membrane is required to provide a rapid response. The minimum isothermal response time varies from (2 ± 1) min near the sea surface to (8 ± 2) min at 60-m depth. Results of field tests, performed in Puget Sound, Washington, during the summer of 2004, are reported, and include preliminary comparisons with mass-spectrometric analysis of in situ water samples analyzed for dissolved N2 and Ar. These tests served as preparations for deployment of two floats by aircraft into the advancing path of Hurricane Frances during September 2004 in the northwest Atlantic. The sensors performed remarkably well in the field. A model of the dynamical response of the GTD to changing hydrostatic pressure that accounts for membrane compressibility effects is presented. The model is used to correct the transient response of the GTD to enable a more precise measurement of gas tension when the float was profiling in the upper-ocean mixed layer beneath the hurricane.

scholarly journals Mixing, heat fluxes and heat content evolution of the Arctic Ocean mixed layer

2011 ◽  
Vol 8 (1) ◽  
pp. 247-289 ◽  
Author(s):  
A. Sirevaag ◽  
S. de la Rosa ◽  
I. Fer ◽  
M. Nicolaus ◽  
M. Tjernström ◽  
...  
Keyword(s):  
Heat Flux ◽  
Solar Radiation ◽  
Arctic Ocean ◽  
Mixed Layer ◽  
Heat Content ◽  
The Arctic ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
The Arctic Ocean ◽  
Melting Season

Abstract. A comprehensive measurement program was conducted during 16 days of a 3 week long ice pack drift, from 15 August to 1 September 2008 in the Central Amundsen Basin, Arctic Ocean. The data, sampled as part of the Arctic Summer Cloud Ocean Study (ASCOS), included upper ocean stratification, mixing and heat transfer as well as transmittance of solar radiation through the ice. The observations give insight into the evolution of the upper layers of the Arctic Ocean in the transition period from melting to freezing. The ocean mixed layer was found to be heated from above and, for summer conditions, the net heat flux through the ice accounted for 22% of the observed change in mixed layer heat content. Heat was mixed downward within the mixed layer and a small, downward heat flux across the pycnocline accounted for the accumulated heat in the upper cold halocline during the melting season. On average, the ocean mixed layer was cooled by an ocean heat flux at the ice/ocean interface (1.2 W m−2) and heated by solar radiation through the ice (−2.6 W m−2). An abrupt change in surface conditions halfway into the drift due to freezing and snowfall showed distinct signatures in the data set and allowed for inferences and comparisons to be made for cases of contrasting forcing conditions. Transmittance of solar radiation was reduced by 59% in the latter period. From hydrographic observations obtained earlier in the melting season, in the same region, we infer a total fresh water equivalent of 3.3 m accumulated in the upper ocean, which together with the observed saltier winter mixed layer indicates a transition towards a more seasonal ice cover in the Arctic.

scholarly journals Upper-Ocean Mixed Layer and Wintertime Sea Surface Temperature Anomalies in the North Pacific

2006 ◽  
Vol 19 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Tomohiko Tomita ◽  
Masami Nonaka
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer ◽  
North Pacific ◽  
Sea Surface ◽  
Upper Ocean ◽  
Ocean Mixed Layer ◽  
The North ◽  
The Impact ◽  
The North Pacific

Abstract In the North Pacific, the wintertime sea surface temperature anomaly (SSTA), which is represented by March (SSTAMar), when the upper-ocean mixed layer depth (hMar) reaches its maximum, is formed by the anomalous surface forcing from fall to winter (S′). As a parameter of volume, hMar has a potential to modify the impact of S′ on SSTAMar. Introducing an upper-ocean heat budget equation, the present study identifies the physical relationship among the spatial distributions of hMar, S′, and SSTAMar. The long-term mean of hMar adjusts the spatial distribution of SSTAMar. Without the adjustment, the impact of S′ on SSTAMar is overestimated where the hMar mean is deep. Since hMar is partially due to seawater temperature, it leads to nonlinearity between the S′ and the SSTAMar. When the SSTAMar is negative (positive), the sensitivity to S′ is impervious (responsive) with the deepening (shoaling) of the hMar compared to the linear sensitivity. The thermal impacts from the ocean to the atmosphere might be underestimated under the assumption of the linear relationship.

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