Interannual Variations of Global UV Radiation in Santiago, Chile (33.5øS)

Abstract

Observations with a four-channel UV radiometer in Santiago, Chile (33.5øS, 70.6øW) from January 1992 to December 1998 are presented. Chinreels are centered at 305, 320, 340 and 380 nm with a 10 nm bandwidth. Measurements were made at one-minute intervals. Hourly mean values at noon for 305 and 340 nm are presented as well as instantaneouisr radiancesf or 60ø of solar zenith angle. Their aperiodic variations on a seasonal scale are discussed with respect to the quasi-biennial oscillation (QBO) and ENSO phenomenaA. significantp ositivet rend that must be caused by decreasingto tal ozonei s found in 305 nm irradimqceO. n a seasonal basis, this negative trend appears strong mqd significant during winter.