Summary
A new multispectral method to derive sea surface emissivity and temperature by using interferometer measurements of the near surface upwelling radiation in the infrared window region is presented. As reflected sky radiation adds substantial spectral variability to the otherwise spectrally smooth surface radiation, an appropriate estimate of surface emissivity allows the measured upwelling radiation to be corrected for the reflected sky component. The remaining radiation, together with the estimated surface emissivity, yields an estimate of the sea surface temperature. Measurements from an ocean pier in the Baltic Sea in October 1995 indicate an accuracy of about 0.1 K for the sea surface temperature thus derived. A strong sea surface skin effect of about 0.6 K is found in that particular case.
Zusammenfassung
Eine neue multispektrale Methode zur Bestimmung von EmissivitÄt und Temperatur der MeeresoberflÄche wird vorgestellt. Die Methode basiert auf spektral hochauflösenden Interferometermessungen der von der MeeresoberflÄche aufwÄrts gerichteten Strahlung im infraroten atmosphÄrischen Fensterbereich. Die abwÄrts gerichtete Himmelsstrahlung, die an der MeeresoberflÄche reflektiert wird, überlagert dem glatten Spektrum der MeeresoberflÄchenemission eine charakteristische spektrale Struktur. Daran kann die spektrale EmissivitÄt der MeeresoberflÄche abgeschÄtzt werden. Damit wird die Korrektur der gemessenen aufwÄrts gerichteten Strahlung und folglich die Bestimmung der MeeresoberflÄchentemperatur möglich. Messungen von einer Seebrücke an der Ostsee im Oktober 1995 zeigen eine absolute Genauigkeit der so ermittelten OberflÄchentemperatur von 0,1 K. Dabei konnte ein Fall mit einem stark ausgeprÄgten Skineffekt von 0,6 K erfa\t werden.
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Fiedler, L., Bakan, S. Interferometric measurements of sea surface temperature and emissivity. Deutsche Hydrographische Zeitschrift 49, 357–365 (1997). https://doi.org/10.1007/BF02764044
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DOI: https://doi.org/10.1007/BF02764044