Analyzing the footprints of near-surface aqueous turbulence: an image processing-based approach

In this contribution, a detailed investigation of surface thermal patterns on the water surface is presented, with wind speeds ranging from 1 to 7 m s − 1 and various surface conditions. Distinct structures can be observed on the surface—small-scale short-lived structures termed fish scales and larg...

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Auteurs principaux: Schnieders, Jana (Auteur) , Garbe, Christoph S. (Auteur) , Peirson, W. L. (Auteur) , Smith, G. B. (Auteur) , Zappa, C. J. (Auteur)
Format: Article (Journal)
Langue:anglais
Publié: 18 March 2013
In: Journal of geophysical research. Oceans
Year: 2013, Volume: 118, Numéro: 3, Pages: 1272-1286
ISSN:2169-9291
DOI:10.1002/jgrc.20102
Accès en ligne:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1002/jgrc.20102
Verlag, lizenzpflichtig, Volltext: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/jgrc.20102
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Notes sur l'auteur:J. Schnieders, C.S. Garbe, W.L. Peirson, G.B. Smith, and C.J. Zappa
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Résumé:In this contribution, a detailed investigation of surface thermal patterns on the water surface is presented, with wind speeds ranging from 1 to 7 m s − 1 and various surface conditions. Distinct structures can be observed on the surface—small-scale short-lived structures termed fish scales and larger-scale cold streaks that are consistent with the footprints of Langmuir circulations. The structure of the surface heat pattern depends strongly on wind-induced stress. Consistent behavior regarding the spacing of cold streaks can be observed in a range of laboratory facilities when expressed as a function of water-sided friction velocity, u * . This behavior systematically decreased until a point of saturation at u * = 0.7 cm/s. We present a new image processing-based approach to the analysis of the spacing of cold streaks based on a machine learning approach to classify the thermal footprints of near-surface turbulence. Comparison is made with studies of Langmuir circulation and the following key points are found. Results suggest a saturation in the tangential stress, anticipating that similar behavior will be observed in the open ocean. A relation to Langmuir numbers shows that thermal footprints in infrared images are consistent with Langmuir circulations and depend strongly on wind wave conditions.
Description:Gesehen am 15.07.2021
Description matérielle:Online Resource
ISSN:2169-9291
DOI:10.1002/jgrc.20102