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Journal of Physics Conference Series 01/2011; 274:012094.
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ABSTRACT: Measurements are presented of UV solar irradiances at 305, 320, 340 and 380 nm and erythemal irradiance on clear-sky days in the city of Buenos Aires, Argentina. These values are compared with data calculated from a radiative atmospheric transfer model. Two quantities of major importance in this model are the ozone and aerosol atmospheric contents. Different values are assigned to them in order to estimate their relative importance in the solar UV irradiance reaching this geographical location. Complementary data on ozone profiles, obtained with the DIAL technique at the same location, are also presented. These spectral and erythemal irradiances are of importance in relation to the biological effects induced in humans by solar UV radiation.
Journal of Optics A Pure and Applied Optics 08/2003; 5(5):S262. · 1.92 Impact Factor
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ABSTRACT: This paper deals with the spectral dependence and time variability of Ångström wavelength exponent scaling law (α), which is the spectral varying slope of the logarithmic relationship between aerosol optical depths (τ) and the wavelength (λ). It is commonly used to retrieve intensive air masses optical properties such as aerosol size distribution from extensive quantities (τ) and Ångström turbidity coefficient (β). This spectral variation of α is studied at different wavelengths from measurements taken by ground-based sun photometer covering from near-infrared to ultraviolet range. We analyze the spectral measurement of aerosols optical depths at eight specific selected wavelengths from 340 to 1020 nm using the sun photometer measurements from AErosol RObotic NETwork (AERONET) from NASA. Data from the entire year 2000 were used from instruments deployed at two different sites covering the regions of Argentina as northcentral at Cordoba CETT (31.5S, 64.4W) and “pampa húmeda” at Buenos Aires CEILAP (34.5S, 58.5W). A new approach of Ångström wavelength exponent spectral variation was developed to take into account with a more accurate precision the significant curvature appearing in the logarithmic relation between τ and λ. Using the direct spectral solar radiation set, time series of Ångström coefficient of turbidity and wavelength scaling law was computed with a day to day data base clustering with uncertainty lower than 0.01 in the optical depth reconstruction over the bulk sun photometer measurements. Temporal series of constant and spectral dependence of wavelength exponent scaling law and turbidity coefficient was derived and shown to vary in space and time. Different meteorological forcing for both sites was evidenced using a regression coefficient analysis to well assess the spectral dependence of wavelength exponent coefficient due to the different cumulating mode of particles and air masses origin at different sites. This spectral decomposition is a key issue in aerosols analysis of steady state and regional scale intrusion episodes with strong connection to their potential contribution of pollution episodes in air-quality problems on urban environment.
Optics and Lasers in Engineering.
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R.D. Piacentini,
E. Luccini,
M.I. Micheletti, E. Quel,
E.A. Wolfram,
A.F. Pazmiño,
J. Fochesatto,
E. Crino,
A. Cede,
M. Blumthaler,
J. Herman,
S. Godin-Beekmann,
G. Mégie
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ABSTRACT: Solar erythemal UV radiation incident on Argentina from tropical to high latitude regions has been measured with ground-based instruments as well as with the TOMS instrument on board of the NASA Earth-Probe satellite. These data permit validation of the UV index, a measure of solar risk to UV exposure, forecasted daily by CONAE (Argentina National Commission on Space Activities) and the Argentine National Weather Service. Model calculations of this index are also presented. In addition, we analyzed the UV effects from the Antarctic ozone hole passing over the continental part of the country using TOMS data corrected by a factor derived front the intercomparison of TOMS satellite data with those determined with Southern Hemisphere ground-based spectroradiometers. In this way, we obtained a rather comprehensive description of the amount of erythemal UV radiation and consequently of the UV index for the entire country, as well as the ozone total column and profile (the latter one at Buenos Aires). The results presented in this work were determined through collaboration between the following institutions: GSFC/NASA in USA, Institute Pierre Simon Laplace in France, University of Innsbruck in Austria and CEILAP, IFIR, CONAE, SMN, Universities of Rosario and San Luis in Argentina. The need to use erythemal irradiance and ozone results in Argentina, one of the most exposed regions of the Southern Hemisphere to study the effects of ozone depletion and consequently UV detrimental effects, has been partially covered in the framework of this North-South collaboration.
Advances in Space Research.
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ABSTRACT: 1) CEILAP (CITEFA-CONICET), Juan B. de La Salle 4397 -B1603ALO Villa Martelli -Argentina. (2) Becario UNSAM (3) Becario Observatorio Pierre Auger (4) IFIR (CONICET -Universidad Nacional de Rosario), Rosario, Argentina (5) Fac. de Cs. Exactas, Ing. Se presentan mediciones de irradiancia espectral solar UV efectuadas en Villa Martelli, Buenos Aires, utilizando un espectroradiómetro computarizado. Los espectros registrados por dicho instrumento, son procesados mediante un software matemático y comparados con resultados obtenidos empleando el algoritmo TUV (Madronich, www.acd.ucar.edu/TUV) que soluciona la ecuación de transferencia radiativa atmosférica y permite evaluar las contribuciones relativas de los componentes atmosféricos. Se presentan además intercomparaciones con otros equipos de sensado remoto pasivo, entre ellos, un radiómetro solar GUV 541 y un radiómetro UV-B EKO MS-210D que registra valores de irradiancia eritémica (indicadora del riesgo solar). Todos los equipos mencionados se encuentran ubicados en el CEILAP (34°33' S 58°30' W, 20 m snm) y se complementan para determinar con mayor precisión esta acción biológica, íntimamente relacionada con el riesgo solar. Measurements of solar UV spectral irradiance made in Villa Martelli, Buenos Aires, using a computarizated spectroradiometer, are presented. The spectra registered by this instrument are processed by means of a mathematical software and compared with results obtained employing the algorithm TUV (Madronich, www.acd.ucar.edu/TUV) that solves the atmospheric radiative transfer equation and it allows to evaluate the relative contributions of the atmospheric components. Intercomparison with other device of passive remote sensing, among them, a GUV 541 solar radiometer and a UV-B EKO MS-210D radiometer that registers values of erythemal irradiance (indicative of the solar risk) are also presented. All the instruments are located at CEILAP (34°33 ' S, 58°30 ' W, 20 m asl) and they complement each other in order to determine with more precision this biological action, intimately related with the solar risk.
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ABSTRACT: As part of the SOLAR field campaign, the CEILAP (CITEFA – CONICET), has developed a mobile tropospheric aerosol lidar system placed in a shelter. This campaign took place in the southern winter-spring period 2005, at Río Gallegos (51,9° S, 69,1° W, 15 m ASL), in Patagonia, Argentina. This lidar and a sunphotometer provided by AERONET (NASA), were used to study aerosols optical properties and boundary layer temporal evolution. This intensive field campaign was supported by JICA, Japan International Cooperation Agency [1], to obtain simultaneous measurements of ozone, water vapor, aerosols vertical profiles and related parameters.
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ABSTRACT: Aerosol characterization is a key parameter to understand its several effects on climate and pollutant transport. For this purpose we use a LIDAR system in combination with a co-located AERONET sunphotometer installed at CEILAP (CITEFA -CONICET) Buenos Aires, Argentina. The aerosol optical thickness retrieved with these instruments is compared in this work. Furthermore, we study this parameter in combination with the Ångström coefficient to estimate the type of aerosol load present in the atmosphere.
