Vitamin D3 - Daily Dose - Forecast:

The Forecast

This is the predicted vitamin D effective daily dose for tomorrow. The prediction is done for a vertically (left) and a horizontally (right) oriented plane receiver.
This forecast enables an estimation of the capacity of the ambient solar radiation in initiating Vitamin D production.
As the thumbnails (March) already indicate, there is a significant difference in the global distribution of the received dose between both orientations.
The difference is largest in the tropics and is vanishing at higher latitudes. Further on seasonsal effects affect the differences.

Additional Information

UV radiation may cause a variety of damages in the human organism. However there are also positive effects to the human like Vitamin D production or influences positively mental health. Deficiencies in Vitamin D lead to rachitis, osteomalicia and influences the progress of osteoporosis which effects 40% of all post-menopausal woman.
In the past years several studies have shown that there is an anti-correlation between Vitamin D level and the risk for several type of cancer (breast, prostate, colon, etc.).
Several tissues of the human body are involved in the Vitamin D metabolism and there is a close connection between different disease and the Vitamin D level.

Information about the actual effectiveness of solar radiation in producing Vitamin D could therefore a very helpful tool for health care. However, one has to keep in mind the damaging potential of UV radiation (for this see our Sun Protection Forecast). A proper intercourse with the sun's rays is the main goal of our forecasts.
As a first step we have introduced this world wide forecast of the vitamin D effective UV radiation for the next day.
The core procedure is a fast spectral UV model, the same as used for the forecast of the erythemally effective UV radiation (Schmalwieser et al. 2001, 2004). A simple preparation scheme (Schmalwieser et al. 2002) is applied to total ozone measurements made by EPTOMS to get appropriate TOC values for the next day.
The forecast is done by using the action spectrum for vitamin D3 production derived by MacLaughlin et al. 1982. This action spectrum ranges from 280nm to 320nm.

Vitamin D levels become critical especially during winter season. The hairless parts of the human head can be regarded as the main receiver for UV radiation during this time of the year.


The forecast is done for a vertical oriented receiver but also for a horizontal one. The vertical orientation corresponds closely to the human face.
In the case of a hairless head plate the horicontal orientation becomes important. The area of the human face is in the order 0.05m2 to 0.07m2. The plate contributes with approximately 0.02m2.
The horizontal orientation is also today's standard orientation for operational measurements. It is less affected by the environment of the measuring station.

Content and realisation (March 12, 2005): alois.schmalwieser()