UV-Radiation
Radiation in the ultraviolet part of the solar spectrum from 280 to 400 nanometer (nm), especially at the shorter UV-B wavelengths from 280 to 315nm, is potentially harmful to humans, animals, and plants. Sunburn is considered as one of the main causes for irreparable damages of the human skin and for the incidence of skin cancer.
By means of radiative transfer simulations an efficient procedure for the calculation and mapping of near surface UV radiation has been generated at the DLR Institute of Atmospheric Physics. This procedure serves as the core of the UV-Check service which has been developed in cooperation between the Institute of Atmospheric Physics and the Berufsverband der Deutschen Dermatologen (BVDD). UV-Check has been made available to the user as smartphone APP and internet service. The service enables a user to quickly request his individual sunburn time at every time and every location within Europe.
The sunburn time is the time in minutes UV radiation until a first perceptible reddening of the unprotected skin. The sunburn time is derived from the erythemally weighted UV irradiance and describes the UV radiant power incident from all directions of the upper hemisphere on a horizontally oriented area. The physical unit is milliwatts per square meter (mW/m2).
In a cloud free atmosphere three parameters are mainly affecting the surface UV radiation: the local sun elevation depending on daytime and day of the year, the amount of ozone within a column ranging from the surface to the top of the atmosphere – the so-called total ozone –, and the elevation of the surface above sea level. At the Institute of Atmospheric Physics a method has been developed and tested by independent measurements that allows for an efficient calculation of the UV irradiance from these three parameters. Of essential importance is the distribution of total ozone. This parameter is measured by the instrument GOME-2 (Global Ozone Monitoring Experiment -2) aboard the European satellite MetOp. Ozone data are continuously received and preprocessed by means of atmospheric models at the DLR German Remote Sensing Data Center.
In a first step, and together with the user’s time of request the UV intensity under clear sky conditions is calculated. In a second step, the UV output is further refined. By interaction with the user specifications associated with local environmental conditions are asked, as for example the cloud cover or regarding terrain properties, snow cover, terrain elevation, and water expanses nearby. Furthermore, the individual skin type is requested and a sun protection factor can be provided as input.
The App, instructions for use, and further scientific-technical or medical-dermatological background information to the UV-Check service is available as free download from several App portals in the web. The user registration is enabled under www.uv-check.de.