UVR models and simulation tools
- The text on this page is taken from an equivalent page of the IEHIAS-project.
Measurements of ultraviolet radiation are available from many atmospheric monitoring stations worldwide, e.g. [1]. However, estimation of human uv exposure from those measurements are not straightforward because they are in principle only valid for the exact times and locations of the measurements. UV simulation models are therefore useful tools to overcome these problems.
Follow links to overview information on those tools and to references of detailed published peer-reviewed scientific papers
- FastRT - Fast simulations of UV doses, indices and irradiances at the Earth's surface. UV indices are the most common proxy for human UV exposure.
- VitD_quartMED - Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status. Estimates how long exposure time is needed to obtain a desired vitamin D dose.
- VitD - Duration of Vitamin D Synthesis in Human Skin. Estimates at which times of day and year vitamin D synthesis is active in skin.
Corresponding simplified web tools for the public:
Contact person: Ola Engelsen, Norwegian Instititute for Air Research, 9296 Tromso, Norway, oen@nilu.no
Model description
Purpose
Exposure of ultraviolet radiation
FastRT - Fast and easy UV simulation tool
Simulations of ultraviolet irradiances, doses and indices at the Earth's surface at user-specified UV wavelengths, locations, times and ambient conditions. This web tool is suitable for assessment of human UV exposure. The program can also be run off-line on the user's computer.
VitD_quartMED - Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status
This online tool estimates the duration of exposure necessary to obtain a desired vitamin D dose. Perhaps even more useful for public guidance than medical research.
VitD - Duration of Vitamin D Synthesis in Human Skin:
This web page estimates at which times of day and year vitamin D synthesis is active in skin. It is used by both the public and epidemiological researchers.
Boundaries
Ultraviolet exposure and its effects in outdoor air. Valid for arbitrary times and locations, but for typical idealized atmospheric conditions only. UV exposure onto a flat, horizonatal surface is taken as a proxy for human skin exposure. See the journal articles below for more exhaustive discussion of limitations of the models.
Input
Requires at least information on time, location, cloudiness, ozone layer classification (thin, medium, thick), altitude and surface type. The model also accepts and accounts for even more detailed information on the ambient conditions.
Output
Either UV intensity (mW m-2), UV dose (J m-2) or exposure time (hours).
Description of processes modelled and of technical details
Run within a web-browser window or on the unix prompt. The latter requires compilation of source code.
Open source. Requires citation of appropriate journal article.
Webb, A.R. and Engelsen, O 2006 Calculated ultraviolet exposure levels for a healthy vitamin D status. Photochemistry and Photobiology 82(6), 1697–1703.
Engelsen O., Brustad, M. Aksnes, L. and Lund, E. 2005 Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness. Photochemistry and Photobiology 81(6), 1287-1290.
Engelsen, O. and Kylling, A. 2005 Fast simulation tool for ultraviolet radiation at the earth’s surface. Optical Engineering 44(4), 041012.1-7.
Rationale
The model has been validated against measurements and other models. For cloudless conditions, the accuracy is at the same level as measurements. Under cloudy conditions, the uncertainties may be substantial, mainly due to the lack of information on the cloud properties.
References
- Webb, A.R. and O. Engelsen (2006) Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status. Photochemistry and Photobiology. 82(6), 1697–1703.
- Engelsen O., M. Brustad, L. Aksnes and E. Lund (2005) Daily Duration of Vitamin D Synthesis in Human Skin with Relation to Latitude, Total Ozone, Altitude, Ground Cover, Aerosols and Cloud Thickness, Photochemistry and Photobiology, 81(6), 1287-1290.
- Engelsen, O. and A. Kylling (2005) Fast simulation tool for ultraviolet radiation at the earth’s surface. Optical Engineering, 44(4), 041012.1-7.