Variations in ocean surface temperature due to near-surface flow : straining the cool skin layer
Wells, Andrew J.
Farrar, J. Thomas
Zappa, Christopher J.
MetadataShow full item record
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 Péclet number, which characterizes the ratio of advection to diffusion within the skin layer. For large Péclet 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 Péclet 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 Péclet number is consistent with the theoretical trends for large Péclet 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.
Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 39 (2009): 2685-2710, doi:10.1175/2009JPO3980.1.
Suggested CitationJournal of Physical Oceanography 39 (2009): 2685-2710
Showing items related by title, author, creator and subject.
What controls seasonal evolution of sea surface temperature in the Bay of Bengal? Mixed layer heat budget analysis using moored buoy observations along 90°E Thangaprakash, V. P.; Girishkumar, M. S.; Suprit, K.; Kumar, N. Suresh; Chaudhuri, Dipanjan; Dinesh, K.; Kumar, Ashok; Shivaprasad, S.; Ravichandran, M.; Farrar, J. Thomas; Sundar, R.; Weller, Robert A. (The Oceanography Society, 2016-06)Continuous time-series measurements of near surface meteorological and ocean variables obtained from Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction (RAMA) moorings at 15°N, 90°E; 12°N, ...
Marine isoprene production and consumption in the mixed layer of the surface ocean – a field study over two oceanic regions Booge, Dennis; Schlundt, Cathleen; Bracher, Astrid; Endres, Sonja; Zäncker, Birthe; Marandino, Christa A. (Copernicus Publications on behalf of the European Geosciences Union, 2018-02-01)Parameterizations of surface ocean isoprene concentrations are numerous, despite the lack of source/sink process understanding. Here we present isoprene and related field measurements in the mixed layer from the Indian ...
Ocean preconditioning of Cyclone Nargis in the Bay of Bengal : interaction between Rossby waves, surface fresh waters, and sea surface temperatures Yu, Lisan; McPhaden, Michael J. (American Meteorological Society, 2011-09)An in-depth data analysis was conducted to understand the occurrence of a strong sea surface temperature (SST) front in the central Bay of Bengal before the formation of Cyclone Nargis in April 2008. Nargis changed its ...