UV-B radiation at Penang

A new series of measurements including global and UV radiation was initiate d in 1994 at Penang. These high quality data were used to study diurnal and seasonal variations. The mean daily total UV-B and global radiation is abo ut 1.43 X 10(4) J and 1.77 X 10(7) J, respectively. Maximum radiation value s for both the UV-B and global radiation are received in March and Septembe r. The daily total global radiation shows a bigger seasonal variation than UV-B radiation. On clear days, the erythemal UV radiation flux is in the hi gh or extreme range for about 5 h beginning at around 1030 hours throughout the year. Penang (5.3 degrees N) and Natal (6 degrees S) are found to exhi bit similar daily maximum erythemal UV irradiance values. A simple empirica l relationship for the noontime UV-B flux and global irradiance in the equa torial/tropical regions has been established. (C) 1999 Published by Elsevie r Science B.V. All rights reserved.