Journal ArticleDOI
Transmittance of a cloud is wavelength‐dependent in the UV‐range
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In this article, the spectral attenuation of the UV-irradiance by a homogeneous cloud-layer at an altitude of about 1200 m was examined and the transmittance of the cloudlayer was found to be wavelength-dependent, ranging from 45% in UVA to 60% in the UVB.Abstract:
Spectral irradiance measured at two stations at different altitudes (the Zugspitze-summit at 2964 m a.s.l. and the Fraunhofer-Institute for Atmospheric Environmental Research at 730 m a.s.l., 8 km apart in horizontal direction) was used to examine the spectral attenuation of the UV-irradiance by a homogeneous cloud-layer at an altitude of about 1200 m. Calculating the ratio of the global spectral irradiance beneath a homogenous cloud-cover (22 October, 1995) to the global spectral irradiance on a cloudless day (24 October, 1995) both measured at the valley station, delivered the spectral transmittance of the cloud. By means of data measured on the Zugspitze on the same two days possible differences in the atmospheric conditions above 2964 m were eliminated and thus the influence of the cloud on the UV-irradiance at Garmisch-Partenkirchen was separated. The transmittance of the cloud-layer was found to be wavelength-dependent, ranging from 45% in the UVA to 60% in the UVB. Therefore it can be assumed that clouds are not generally “grey” (i.e. that the attenuation is dependent on wavelength).read more
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Changes in biologically active ultraviolet radiation reaching the Earth's surface
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Changes in biologically-active ultraviolet radiation reaching the Earth's surface
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Empirical studies of cloud effects on UV radiation: A review
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Solar and ultraviolet radiation
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Composition changes after the "Halloween" solar proton event: the High Energy Particle Precipitation in the Atmosphere (HEPPA) model versus MIPAS data intercomparison study
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References
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Journal ArticleDOI
Solar spectral irradiance under clear and cloudy skies : measurements and a semiempirical model
Stefan Nann,Carol Riordan +1 more
TL;DR: In this article, the authors developed a semi-empirical model that describes the total solar spectral irradiance for clear and cloudy sky conditions based on readily available input data, which was applied to calculate spectral irradiances in short time.
Journal ArticleDOI
The ultraviolet radiation environment of the Antarctic Peninsula : the roles of ozone and cloud cover
Dan Lubin,John E. Frederick +1 more
TL;DR: The National Science Foundation scanning spectroradiometer at Palmer Station, Antarctica (64°46′S, 64°04′W) provides hourly ground-based measurements of solar ultraviolet (UV) irradiance at the, earth's surface as mentioned in this paper.
Journal ArticleDOI
UV‐B in Germany higher in 1993 than in 1992
TL;DR: A comparison of spectral UV measurements between 1992 and 1993 showed increased levels of UV-B radiation in late spring and early summer of 1993 caused by reduced total ozone columns in Southern Germany as mentioned in this paper.
Journal ArticleDOI
Tropospheric Influence on Solar Ultraviolet Radiation: The Role of Clouds.
TL;DR: The role of cloud cover in moderating biologically effective ultraviolet radiation at the Earth's surface is discussed in this paper, where the authors estimate the response of erythemal irradiance to variations in fractional cloud cover and cloud optical thickness.
Journal ArticleDOI
Solar ultraviolet radiation in southeast england: the case for spectral measurements
TL;DR: In this paper, the daily and annual changes in the ultraviolet-B (UV-B) part of the spectrum, and illustrate the dominance of the longer wavelengths in grouping the data into a single broadband measurement.