Trends in the Solar Radiation Level UV-B in the Spring-Winter of 1998 Between latitudes 18°S and 33°S

. SUMMARY - Are presented results of dose measurements erythemical solar effected between July - October of 1998, during the period that understands winter and beginning end of spring. The measurements in Arica (Lat.: 18º 29´S, Long.: 70o 19´ 23 m. a.s.l.) were acomplished using radiómeter IL-400, with sensors calibrated in U.S.A. that they permit measure erythemical doses. The maximum values daily obtained, was compared with the maximum values of solar UV-B irradiance obtained by the Meteorological Center of Chile through equipment YES with sensors that measure the ultraviolet radiative flow with lengths of wave between 0.280-0.330 microns, in the cities of Iquique (Lat.:20o 32´S, Long.: 70o 11´W) and Santiago (Lat.:33o 23´S, Long.: 70o 47´W). These results are published monthly in an edited bulletin for this Meteorological Officce. In the case of Arica were obtained the values of the thickness of the ozone cap measured through the instrument TOMS of NASA, during the same period. The obtained results show that the trends in increase in the levels of ultraviolet solar radiation obtained in Arica as well as in Iquique due to station change spring winter vary between a 45% respect to the local daily maximum to beginning of the month of July until arriving to a 100% in October, these changes in the case of Arica are not doubt to variations observed in the thickness of the ozone layer those which in these latitudes are inferior to a 5% in the same period of tim