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Deutsche Hydrografische Zeitschrift

, Volume 48, Issue 2, pp 121–132 | Cite as

Sunglitter radiance modulation by internal waves

  • Ingo Hennings
  • Margitta Metzner
Articles

Summary

Quantitative sunglitter radiance modulations at the ocean surface due to internal waves were calculated applying a simple first order theory. The results have been compared with the image data of internal wave signatures northeast of Nantucket Shoals off the coast of Massachusetts, U.S.A., taken by the Earth Terrain Camera (ETC) during the Skylab mission. The maximum magnitudes of sunglitter radiance modulations predicted by the theory are comparable to the satellite image data. The extreme values of calculated modulations depend only weakly on the wavelength of the internal wave signature. This is consistent with the analysed ETC data. On the other hand, the shapes of simulated and measured image intensity transects across an internal wave packet are different. This may possibly be explained by the assumed idealized sinusoidal type of thermocline used in the calculations. The theory predicts that sunglint signatures of internal waves are advected relative to positions of extreme slope regions of the thermocline due to currents.

Keywords

Internal Wave Sand Wave German Journal Interactive Data Language Nonlinear Internal Wave 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Strahldichtemodulation des Sonnenglitzerns durch interne Wellen

Zusammenfassung

Quantitative Strahldichtemodulationen des Sonnenglitzerns an der Meeresoberfläche durch interne Wellen werden unter Verwendung einer einfachen ersten Ordnungstheorie berechnet. Die Ergebnisse werden mit Bilddaten von internen Wellensignaturen nordöstlich von Nantucket Shoals vor der Küste von Massachusetts, U.S.A., verglichen, die während der Skylab-Mission von der Erdbeobachtungskamera (ETC) aufgenommen wurden. Die Werte der maximalen Strahldichtemodulation des Sonnenglitzerns, die von der Theorie vorhergesagt werden, sind mit den Satellitenbilddaten vergleichbar. Die Extremwerte der berechneten Modulationen hängen nur schwach von der Wellenlänge der internen Wellensignaturen ab. Dieses stimmt mit den analysierten ETC Daten überein. Auf der anderen Seite sind die Kurvenverläufe zwischen den simulierten und gemessenen Bildintensitätsprofilen entlang eines internen Wellenpaketes unterschiedlich. Dieses kann möglicherweise durch den angenommenen idealisierten sinusförmigen Typ der Thermokline erklärt werden, der für die Berechnungen verwendet wurde. Die Theorie macht die Vorhersage, daß Signaturen des Sonnenglitzerns von internen Wellen durch Strömungen advektiert werden relativ zu den Positionen der extremen Neigungsregionen der Thermokline.

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Copyright information

© BSH, Hamburg und Rostock 1996

Authors and Affiliations

  1. 1.GEOMARForschungszentrum für Marine Geowissenschaften der Christian-Albrechts-Universität zu KielKielGermany
  2. 2.Geodätisches Institut der Universität StuttgartStuttgartGermany

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