The solar radiation at Earth surface is measured usually with instruments of narrow or large wavelengths bands. However, for different applications like the determination of irradiances related to biological actions and substance and material degradations, it is needed to know the spectrum at all wavelengths with reasonable resolution. In CEILAP (CONICET - CITEFA) placed at the Gran Buenos Aires suburbs (34° 33' S, 58° 30' W, 20 m asl), we made measurements of solar UV irradiance in clear sky days in the UV range (300 - 400 nm) range with a spectroradiometer Monospec 27 of National University of Rosario. The data represented in a 3D diagram show the variations in the solar spectrum along the day as function of the solar zenith angle. From the comparison with the results obtained employing the TUV program developed by Madronich/NCAR that solves the radiative transfer equation, it is possible to determine the influence of the <i>ozone</i> and <i>aerosol</i> atmospheric components on this irradiance. The spectra were calibrated against the absolute measurements made with an instrument GUV 541 at wavelengths of 305, 320, 340 and 380 nm, which is placed in the same building and was recently calibrated.
We present results of measurements and atmospheric radiative model calculations of erythemal and 305 nm solar irradiances measured at Buenos Aires (34° 36' S, 58° 30' W, 20 m a.s.l.). Complementary data on ozone profile obtained with the DIAL technique are also presented. The solar irradiance values are of importance for evaluation of solar risk through the UV index and DNA damage.
An analysis of aerosols optical parameters is made using the sun photometer measurements taken at CEILAP in 2000. The sun photometer deployed in the Buenos Aires suburb is part of AERONET. Using the present data set, time series of key optical parameters such as the optical depth at 500 nm and Angstrom coefficient of the wavelength scaling law are derived. Clustering the observations by mean of a statistical analysis we can infer the pollution episodes in the Buenos Aires area. They can be either of local or regional origins, depending on the meteorological conditions prevailing over central Argentina.
A ground-based differential Absorption Lidar (DIAL) system has been implemented at CEILAP laboratory, located in the Buenos Aires industrial suburbs, The goal was to perform measurements of the stratospheric ozone layer. Since early 199 systematic measurements of zone concentration profiles from approximately 18 to 35 km altitude are performed. Our measurements are carried out in 5 hours in average during the night and in cloudless conditions. The DIAL system allows us to calculate directly the ozone profile from the lidar backscattering radiation since it is a self- calibrating technique. The signals processing takes into account the influence of the temperature profile on the ozone cross section. The temperature data is obtained from the radiosondes measurements performed at Ezeira International Airport. The evolution of the stratospheric ozone profile is studied for different months. Results are compared with the data obtained by different satellites like SAGE II and HALOE. The spatial and temporal range of the satellites must be taken into account.