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M. Schrempf
Institut für Meteorologie und Klimatologie, Leibniz Universität Hannover

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Journal article
Published: 29 August 2017 in Aktuelle Dermatologie
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Zusammenfassung Die Vitamin-D3-gewichtete UV-Exposition eines aufrecht stehenden Menschen wurde für ausgewählte urbane Umgebungen bestimmt, um den Einfluss der Verschattung durch Gebäude oder Bewuchs auf die Exposition zu untersuchen. Die Exposition wird berechnet unter Berücksichtigung der Strahldichte, also der Strahlungsenergie von direkter Sonnenstrahlung und diffuser Himmelsstrahlung aus verschiedenen Einfalls- und Azimutwinkeln und der 3 D-Geometrie eines Modellmenschen. Die Verschattung wird durch Hemisphären-Bilder bestimmt, die mithilfe einer Fotokamera mit Fischaugenobjektiv aufgenommen wurden, wobei angenommen wird, dass die Strahlung verschatteter Himmelssegmente vernachlässigbar klein ist. Dadurch werden den Himmel verdeckende Hindernisse räumlich hochaufgelöst erfasst und als Input in das Expositionsmodell eingegeben. Die Vitamin-D3-gewichtete Exposition betrug an einer bebauten Straße am 21. Dezember zu Sonnenhöchststand ungefähr 50 % und am 21. März 70 % von der Exposition einer hindernisfreien Umgebung.

ACS Style

M. Schrempf; N. Thuns; K. Lange; G. Seckmeyer. Einfluss der Verschattung auf die Vitamin-D-gewichtete UV-Exposition eines Menschen. Aktuelle Dermatologie 2017, 44, 204 -209.

AMA Style

M. Schrempf, N. Thuns, K. Lange, G. Seckmeyer. Einfluss der Verschattung auf die Vitamin-D-gewichtete UV-Exposition eines Menschen. Aktuelle Dermatologie. 2017; 44 (05):204-209.

Chicago/Turabian Style

M. Schrempf; N. Thuns; K. Lange; G. Seckmeyer. 2017. "Einfluss der Verschattung auf die Vitamin-D-gewichtete UV-Exposition eines Menschen." Aktuelle Dermatologie 44, no. 05: 204-209.

Journal article
Published: 16 August 2017 in International Journal of Environmental Research and Public Health
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The vitamin D3-weighted UV exposure of a human with vertical posture was calculated for urban locations to investigate the impact of orientation and obstructions on the exposure. Human exposure was calculated by using the 3D geometry of a human and integrating the radiance, i.e., the radiant energy from the direct solar beam and the diffuse sky radiation from different incident and azimuth angles. Obstructions of the sky are derived from hemispherical images, which are recorded by a digital camera with a fisheye lens. Due to the low reflectivity of most surfaces in the UV range, the radiance from obstructed sky regions was neglected. For spring equinox (21 March), the exposure of a human model with winter clothing in an environment where obstructions cover 40% of the sky varies by up to 25%, depending on the orientation of the human model to the sun. The calculation of the accumulated vitamin D3-weighted exposure of a human with winter clothing walking during lunch break shows that human exposure is reduced by the obstruction of buildings and vegetation by 40%.

ACS Style

Michael Schrempf; Nadine Thuns; Kezia Lange; Gunther Seckmeyer. Impact of Orientation on the Vitamin D Weighted Exposure of a Human in an Urban Environment. International Journal of Environmental Research and Public Health 2017, 14, 920 .

AMA Style

Michael Schrempf, Nadine Thuns, Kezia Lange, Gunther Seckmeyer. Impact of Orientation on the Vitamin D Weighted Exposure of a Human in an Urban Environment. International Journal of Environmental Research and Public Health. 2017; 14 (8):920.

Chicago/Turabian Style

Michael Schrempf; Nadine Thuns; Kezia Lange; Gunther Seckmeyer. 2017. "Impact of Orientation on the Vitamin D Weighted Exposure of a Human in an Urban Environment." International Journal of Environmental Research and Public Health 14, no. 8: 920.

Journal article
Published: 28 September 2016 in International Journal of Environmental Research and Public Health
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In a recent study, melanoma incidence rates for Austrian inhabitants living at higher altitudes were found to increase by as much as 30% per 100 m altitude. This strong increase cannot simply be explained by the known increase of erythemally-weighted irradiance with altitude, which ranges between 0.5% and 4% per 100 m. We assume that the discrepancy is partially explainable by upwelling UV radiation; e.g., reflected by snow-covered surfaces. Therefore, we present an approach where the human UV exposure is derived by integrating incident radiation over the 3D geometry of a human body, which enables us to take upwelling radiation into account. Calculating upwelling and downwelling radiance with a radiative transfer model for a snow-free valley and for snow-covered mountain terrain (with albedo of 0.6) yields an increase in UV exposure by 10% per 100 m altitude. The results imply that upwelling radiation plays a significant role in the increase of melanoma incidence with altitude.

ACS Style

Michael Schrempf; Daniela Haluza; Stana Simic; Stefan Riechelmann; Kathrin Graw; Gunther Seckmeyer. Is Multidirectional UV Exposure Responsible for Increasing Melanoma Prevalence with Altitude? A Hypothesis Based on Calculations with a 3D-Human Exposure Model. International Journal of Environmental Research and Public Health 2016, 13, 961 .

AMA Style

Michael Schrempf, Daniela Haluza, Stana Simic, Stefan Riechelmann, Kathrin Graw, Gunther Seckmeyer. Is Multidirectional UV Exposure Responsible for Increasing Melanoma Prevalence with Altitude? A Hypothesis Based on Calculations with a 3D-Human Exposure Model. International Journal of Environmental Research and Public Health. 2016; 13 (10):961.

Chicago/Turabian Style

Michael Schrempf; Daniela Haluza; Stana Simic; Stefan Riechelmann; Kathrin Graw; Gunther Seckmeyer. 2016. "Is Multidirectional UV Exposure Responsible for Increasing Melanoma Prevalence with Altitude? A Hypothesis Based on Calculations with a 3D-Human Exposure Model." International Journal of Environmental Research and Public Health 13, no. 10: 961.

Preprint content
Published: 18 December 2013 in Atmospheric Measurement Techniques Discussions
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Cloud Fractional Cover (CFC) derived from Spinning Enhanced Visible and Infrared Imager (SEVIRI) on a geostationary satellite and from the Advanced Very High Resolution Radiometer (AVHRR) on polar orbiters, was validated against ground-based observations in Hannover, Germany (three months of data) and Lauder, New Zealand (only AVHRR, two months of data). The ground-based cloud coverage data consists of synoptical data and imagery taken by a Hemispherical Sky Imager. The standard deviation of the differences between the daily mean CFC derived by SEVIRI and synoptical data was satisfactory, but it was 100% larger than the deviations of the differences between SEVIRI and those derived by the hemispherical sky imager. For the instantaneous CFC, clear and completely overcast skies are well detected in the satellite products. During broken cloud coverage the agreement between ground-based data from the hemispherical sky imager and data from satellite is mostly uncorrelated. The standard deviations of the differences between AVHRR and the imager (instantaneous and daily mean data) were smaller than those between SEVIRI and imager. In Lauder, New Zealand, only data from the hemispherical sky imager and AVHRR was available. The standard deviations of the differences were slightly higher than in Hannover, Germany. In addition we found that the SEVIRI algorithm systematically overestimates the cloud coverage. We therefore suggest to refine the parameterization of the cloud contamination factor in the algorithms for the derivation of CFC.

ACS Style

A. Werkmeister; M. Schrempf; K. Tohsing; M. Lockhoff; B. Liley; G. Seckmeyer. Validation of CM SAF cloud fractions: can cloud cover be reliably derived by satellite data at Hannover, Germany and Lauder, New Zealand? – a comment. Atmospheric Measurement Techniques Discussions 2013, 1 .

AMA Style

A. Werkmeister, M. Schrempf, K. Tohsing, M. Lockhoff, B. Liley, G. Seckmeyer. Validation of CM SAF cloud fractions: can cloud cover be reliably derived by satellite data at Hannover, Germany and Lauder, New Zealand? – a comment. Atmospheric Measurement Techniques Discussions. 2013; ():1.

Chicago/Turabian Style

A. Werkmeister; M. Schrempf; K. Tohsing; M. Lockhoff; B. Liley; G. Seckmeyer. 2013. "Validation of CM SAF cloud fractions: can cloud cover be reliably derived by satellite data at Hannover, Germany and Lauder, New Zealand? – a comment." Atmospheric Measurement Techniques Discussions , no. : 1.