On the Thermal Boundary Layer of the Ocean

Ewing, Gifford C.; McAlister, E. D.

doi:10.1126/science.131.3410.1374

Cited by 89 publications

(35 citation statements)

References 2 publications

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“…Other laboratory experiments (e.g., Ewing and McAlister 1960) showed that the skin layer can reestablish itself within 9-12 s after it is destroyed by a breaking wave. More recent infrared camera measurements have demonstrated that the skin layer has the ability to restore itself in as little as 1 s (Jessup et al 1997).…”

Section: B Likelihood Of the Existence Of Strong Salinity Stratificamentioning

confidence: 99%

“…The significance of correcting the cool skin for improving the absolute accuracy of satellite measurements of SST has further stimulated research into the physical processes that determine the near-surface thermal structure and the cause of the skin-bulk difference (e.g., Ewing and McAlister 1960;Hasse 1963;Saunders 1967;Liu and Businger 1975;Liu et al 1979;Katsaros et al 1977;Katsaros 1980;Paulson and Simpson 1981;Robinson et al 1984;Schlü ssel et al 1990;Fairall et al 1996;Wick et al 1996;Katsaros and Soloviev 2004). The appearance of a cool skin layer is due to (i) the combined cooling effects of net longwave radiation, evaporation, and sensible heat flux from the sea surface to the atmosphere and (ii) the transport of heat by molecular conduction in the skin layer instead of turbulent mixing (Hasse 1971;Katsaros 1980;Schlü ssel et al 1990;Fairall et al 1996).…”

Section: Introductionmentioning

confidence: 99%

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On Sea Surface Salinity Skin Effect Induced by Evaporation and Implications for Remote Sensing of Ocean Salinity

2010

Journal of Physical Oceanography

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The existence of a cool and salty sea surface skin under evaporation was first proposed by Saunders in 1967, but few efforts have since been made to perceive the salt component of the skin layer. With two salinity missions scheduled to launch in the coming years, this study attempted to revisit the Saunders concept and to utilize presently available air-sea forcing datasets to analyze, understand, and interpret the effect of the salty skin and its implication for remote sensing of ocean salinity.Similar to surface cooling, the skin salinification would occur primarily at low and midlatitudes in regions that are characterized by low winds or high evaporation. On average, the skin is saltier than the interior water by 0.05-0.15 psu and cooler by 0.28-0.58C. The cooler and saltier skin at the top is always statically unstable, and the tendency to overturn is controlled by cooling. Once the skin layer overturns, the time to reestablish the full increase of skin salinity was reported to be on the order of 15 min, which is approximately 90 times slower than that for skin temperature. Because the radiation received from a footprint is averaged over an area to give a single pixel value, the slow recovery by the salt diffusion process might cause a slight reduction in area-averaged skin salinity and thus obscure the salty skin effect on radiometer retrievals. In the presence of many geophysical error sources in remote sensing of ocean salinity, the salt enrichment at the surface skin does not appear to be a concern.

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Section: B Likelihood Of the Existence Of Strong Salinity Stratificamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On Sea Surface Salinity Skin Effect Induced by Evaporation and Implications for Remote Sensing of Ocean Salinity

2010

Journal of Physical Oceanography

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“…Experimental studies have mostly focused on measuring transfer properties averaged over large spatial regions; very few have directly examined the influence of a straining flow on the skin layer. Ewing and McAlister (1960) demonstrated that a turbulent jet directed toward the interface can modify the skin temperature, and Leighton et al (2003) showed that direct numerical simulations of free convection were well described by a surface straining model. However, there has been no quantitative experimental evaluation of the direct influence of a straining flow on the skin temperature.…”

Section: Introductionmentioning

confidence: 99%

Variations in Ocean Surface Temperature due to Near-Surface Flow: Straining the Cool Skin Layer

Wells

Cenedese

Farrar

et al. 2009

Journal of Physical Oceanography

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The aqueous thermal boundary layer near to the ocean surface, or skin layer, has thickness O(1 mm) and plays an important role in controlling the exchange of heat between the atmosphere and the ocean. Theoretical arguments and experimental measurements are used to investigate the dynamics of the skin layer under the influence of an upwelling flow, which is imposed in addition to free convection below a cooled water surface. Previous theories of straining flow in the skin layer are considered and a simple extension of a surface straining model is posed to describe the combination of turbulence and an upwelling flow. An additional theory is also proposed, conceptually based on the buoyancy-driven instability of a laminar straining flow cooled from above. In all three theories considered two distinct regimes are observed for different values of the Pé clet number, which characterizes the ratio of advection to diffusion within the skin layer. For large Pé clet numbers, the upwelling flow dominates and increases the free surface temperature, or skin temperature, to follow the scaling expected for a laminar straining flow. For small Pé clet numbers, it is shown that any flow that is steady or varies over long time scales produces only a small change in skin temperature by direct straining of the skin layer. Experimental measurements demonstrate that a strong upwelling flow increases the skin temperature and suggest that the mean change in skin temperature with Pé clet number is consistent with the theoretical trends for large Pé clet number flow. However, all of the models considered consistently underpredict the measured skin temperature, both with and without an upwelling flow, possibly a result of surfactant effects not included in the models.

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“…Most longwave radiation emitted by a water surface is produced in the first 100 ^m below the water surface (McAlister and McLeish, 1969). Ewing and McAlister (1960) found that the temperatures within this layer may differ significantly from that temperature which would be measured with the smallest conventional temperature measuring device placed as close to the water surface as possible. The true surface temperature is generally found to be lower than the bulk water temperature.…”

Section: Pcpymentioning

confidence: 99%