Medically important solar ultraviolet A. Radiation measurements.

Results from a 6-year study of solar ultraviolet A (UVA) radiation measurements at the equatorial location of Penang (5 degrees N) are presented. On clear days, the diurnal flux reaches a very high dosage of about 3.0 x 10(-2) KWHM-2 around midday. The average daily total flux is in the range of 1.6 x 10(-1) KWHM-2 and does not change much seasonally. The high 83% cloud cover only reduces the incoming flux to about half. The radiation flux represents a lower limit of the incident UVA radiation applicable to much of the equatorial/tropical region.