SMuK 2021 – wissenschaftliches Programm
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UP: Fachverband Umweltphysik
UP 6: Poster Session
UP 6.2: Poster
Freitag, 3. September 2021, 16:30–18:30, P
Modelling optical twilight phenomena: Earth's shadow and the Belt of Venus — •Anna Lange1, Alexei Rozanov2, and Christian von Savigny1 — 1Institute of Physics, University of Greifswald, Germany — 2Institute of Environmental Physics, University of Bremen, Germany
During clear civil twilights it is possible to see a combination of two optical phenomena above the antisolar horizon: The earth's shadow and the Belt of Venus (or antitwilight arch). Simulations with the radiative transfer model SCIATRAN and colour modelling based on the CIE (International Commission on Illumination) colour matching functions and CIE chromaticity values reproduce the phenomena accurately. Investigations on the influence of ozone show that it has a strong impact on the colours of both twilight phenomena. Although the Chappuis bands are clearly visible in the spectra of all segments, the colour of the earth's shadow differs from the sky above the antitwilight arch. Furthermore, a low optical depth in the troposphere is necessary to simulate the reddish colour of the Belt of Venus.