Solar Radiation

What we will call "current solar radiation" is more specifically known as Global Solar Radiation, a measure of the intensity of the sun's radiation reaching a horizontal surface. This irradiance includes both the sun's direct beam radiation and the reflected/scattered component from the sky. The solar radiation reading gives a measure of the amount of solar radiation hitting the sensor at any given time and is expressed in Watts per square meter. The solar sensor detects radiation at wavelengths of 400 to 1100 nanometers.

Ultra Violet (UV) Radiation

Energy from the sun in the UV portion of the electromagnetic spectrum also reaches the Earth. Exposure to this type of radiation can cause many health problems, such as sunburn, skin cancer, premature skin aging, cataracts and others. The UV sensor detects radiation at wavelengths of 290 to 390 nanometers. Readings are given in two different scales: MEDs and UV Index. Currently we are measuring in UV Index.

MED stands for Minimum Erythemal Dose and is defined as the amount of sun exposure that is necessary to produce a barely perceptible redness of the skin within 24 hrs after exposure to the sun. Just 1 MED will therefore result in skin redness. The response of a person's skin to 1 MED will vary since skin type/burning rates vary from person to person.

UV Index is an intensity measurement that was first defined by Environment Canada and has been adopted by the World Meteorological Organization (WMO). The UV Index scale ranges from 0 to 16 where the higher the number, the higher the danger of sunburn. In the newspaper or on TV, the published UV Index forecast is for the next day's noontime UV intensity. The value from our weather station is a real-time measurement.

!!!Be aware that the readings do not suggest that any amount of exposure is safe or healthful. Do not use the value to determine the amount of UV radiation to which you expose yourself. Scientific evidence suggests that UV exposure should be avoided and that even low UV doses can be harmful!!!