Systematic ozone and solar UV measurements in the Observatorio Atmosférico de la Patagonia Austral, Argentina

The depletion of the polar ozone layer is one of the strongest anthropogenic signals in the Earth system. Subpolar regions in the southern part of South America are affected by this phenomenon, covered sometimes by air masses with less ozone than normal with the corresponding UV enhancements at ground surface. Motivated by these atmospheric events, Argentina and Chile with the financial support of JICA has joined scientific efforts to develop UVO Patagonia project. The Observatorio Atmosférico de la Patagonia Austral is located in South Patagonia (51º 55?S, 69º 14'W), in the subpolar region and it is a convenient monitoring site of the atmosphere in the Southern Hemisphere. In this experimental site a differential absorption lidar instrument for the measurement of ozone vertical distribution is operative. The altitude range of the ozone measurement is 14-45 km, which provides the opportunity to monitor the turbulences due to the passage of stratospheric polar air over Río Gallegos. Systematic stratospheric ozone profile measurement has been carried on in this experimental site since 2005. We identified three major perturbations of the ozone hole over the stratospheric ozone profile in Río Gallegos. Approach of polar vortex during late winter, overpass of ozone hole in middle spring and dilution process during late spring change the shape and content of stratospheric ozone profile and as a consequence the solar UV. Solar surface irradiance and total ozone content were measured with a Brewer spectraphotometer and moderate narrow band radiometer GUV-541 deployed in the Río Gallegos experimental site.Fil: Wolfram, Elian Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Salvador, Jacobo Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Orte, Pablo Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: D'elia, Raul Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Casiccia, Claudio. Universidad de Magallanes; ChileFil: Zamorano, Felix. Universidad de Magallanes; ChileFil: Paes Leme, Neusa. Centro de Previsao de Tempo e Estudos Climáticos. Instituto Nacional de Pesquisas Espaciais; Brasi

Ozone profile measurements at Atmospheric Observatory of South Patagonia, Argentina

The Atmospheric Observatory of Austral Patagonia (OAPA) is a remote sensing site located near the Río Gallegos city in South Patagonia (51º 55'S, 69º 14'W), in subpolar region affected by the polar vortex. It is a convenient monitoring site of the atmosphere in the southern hemisphere especially for ozone studies. This site is operating a differential absorption lidar instrument (DIAL) for the measurement of ozone vertical distribution. This instrument is part of Network Data for Atmospheric Composition Change (NDACC). The altitude range of the ozone measurement is 14-45 km, which provides the opportunity to monitor the perturbations due to the passage of stratospheric polar air over Río Gallegos. Since 2005, systematic stratospheric ozone profile measurements have been carried on in this experimental site. The position of the station with respect to the polar vortex was analyzed from the use of equivalent latitude maps. We identified three major perturbation related to the ozone hole on the stratospheric ozone profile record in Río Gallegos: extension of the polar vortex towards the station during late winter, passage of the ozone hole over the station in middle spring and dilution process during late spring. All these three processes change the shape of the stratospheric ozone profile and produce variation in the total ozone column over the OAPA. These perturbations in the middle atmosphere induce change in solar UV radiation at ground surface of great importance for the health of people leaving in the area. In this article, we review the main conclusions regarding the observation of stratospheric ozone profiles measurements OAPA and surface UV radiation for the period 2005-2011

New differential absorption lidar for stratospheric ozone monitoring in Patagonia, South Argentina

International audienceAs part of environmental studies concerned with measurements of the stratospheric ozone layer, CEILAP has developed a new differential absorption lidar (DIAL) instrument. Since the initial construction of the first DIAL instrument, the Lidar Division of CEILAP has made important financial and scientific investments to upgrade this initial prototype. The new version has a bigger reception system formed by four Newtonian telescopes, each of 50 cm diameter, and a larger number of detection channels: four different wavelengths are detected simultaneously and six digital channels record the Rayleigh and Raman backscattered photons emitted by a ClXe excimer laser at 308 nm and the third harmonic of a Nd–YAG laser at 355 nm. A number of different changes have been made to increase the dynamic range of this lidar: a mechanical chopper was installed together with a gated photomultiplier in the high-energy detection channels to avoid the detector being overloaded by strong signals from lower atmospheric layers. This new version was installed inside a shelter, giving the possibility to make field campaigns outside CEILAP laboratories, for example the SOLAR campaign made in the Argentine Patagonian region during 2005 and 2006 spring periods. In this paper a full description of the instrument update is given. Intercomparisons with the ozone sonde and satellite platform instrument are presented. The results show agreement better than 10% in 16–38 km altitude range when the same airmasses are sampled. The comparison with five quasi-coincident sondes launched in Punta Arenas during spring 2005 shows good agreement between both types of measurement, with relative differences inside 1σ deviation of the lidar measurement. The comparison of the integral of height integrated lidar profiles with total ozone column measured with a Brewer photometer shows good agreement, with relative differences less than 10%

Multichannel radiometer calibration: A new approach

The error in irradiance measured with Sun-calibrated multichannel radiometers may be large when the solar zenith angle (SZA) increases. This could be particularly detrimental in radiometers installed at mid and high latitudes, where SZAs at noon are larger than 50° during part of the year. When a multi-regressive methodology, including the total ozone column and SZA, was applied in the calculation of the calibration constant, an important improvement was observed. By combining two different equations, an improvement was obtained at almost all the SZAs in the calibration. An independent test that compared the irradiance of a multichannel instrument and a spectroradiometer installed in Ushuaia, Argentina, was used to confirm the results.Fil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Booth, Charles R.. Biospherical Instruments Inc.; Estados UnidosFil: Armstrong, Roy. Universidad de Puerto Rico; Puerto RicoFil: Brunat, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Inter-American Institute for Global Change Research; ArgentinaFil: Cabrera, Sergio. Universidad de Chile; ChileFil: Camilion, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Casiccia, Claudio. Universidad de Magallanes; ChileFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fuenzalida, Humberto. Universidad de Chile; ChileFil: Lovengreen, Charlotte. Universidad Austral de Chile; ChileFil: Paladini, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Pedroni, Jorge. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Rosales, Alejandro. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Zagarese, Horacio Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Vernet, Maria. University of California; Estados Unido

Quality of UVR exposure for different biological systems along a latitudinal gradient

The exposure of organisms to ultraviolet radiation (UVR) is characterized by the climatology (annual cycle) and the variance (anomalies) of biologically-weighted irradiances at eight geographical locations in austral South America, from 1995-2002. The net effect of UVR on biological systems is a result of the balance of damage and repair which depends on intensity and duration of irradiance and is modulated by its variability. The emphasis in this study is on day-to-day variability, a time scale of importance to adaptive strategies that counteract UVR damage. The irradiances were weighted with DNA- and phytoplankton photosynthesis-action spectra. Low latitude sites show high average UVR. For all sites, the frequency of days with above average irradiances is higher than below average irradiances. Persistence in anomalies is generally low (≤0.36 autocorrelation coefficient), but higher for DNA- than phytoplankton photosynthesis-weighted irradiances due to their higher correspondence to

Availability of vitamin D photoconversion weighted UV radiation in southern South America

Ultraviolet radiation (UVR) plays a key role in several biological functions, including human health. Skin exposure to UVR is the main factor in vitamin D photoconversion. There is also evidence relating low levels of vitamin D with certain internal cancers, mainly colon, breast and prostate, as well as other diseases. Several epidemiological studies have shown an inverse relationship between the above-mentioned diseases and latitude, in accordance with the ultraviolet radiation latitudinal gradient. The aim of this study is to determine whether UV irradiance levels in the southern South America are sufficient to produce suitable levels of vitamin D year around. For this purpose, vitamin D photoconversion weighted-irradiance was analyzed between S.S. de Jujuy (24.17°S, 65.02°W) and Ushuaia (54° 50′S, 68° 18′W). In addition to irradiance, skin type and area of body exposed to sunlight are critical factors in vitamin D epidemiology. Due to a broad ethnic variability, it was assumed that the skin type in this region varies between II and V (from the most to the less sensitive). All sites except South Patagonia indicate that skin II under any condition of body area exposure and skin V when exposing head, hands, arms and legs, would produce suitable levels of vitamin D year round (except for some days in winter at North Patagonian sites). At South Patagonian sites, minimum healthy levels of vitamin D year round can be reached only by the more sensitive skin II type, if exposing head, hands, arms and legs, which is not a realistic scenario during winter. At these southern latitudes, healthy vitamin D levels would not be obtained between mid May and beginning of August if exposing only the head. Skin V with head exposure is the most critical situation; with the exception of the tropics, sun exposure would not produce suitable levels of vitamin D around winter, during a time period that varies with latitude. Analyzing the best exposure time during the day in order to obtain a suitable level of vitamin D without risk of sunburn, it was concluded that noon is best during winter, as determined previously. For skin type II when exposing head, exposure period in winter varies between 30 and 130 min, according to latitude, except for South Patagonian sites. During summer, noon seems to be a good time of day for short periods of exposure, while during leisure times, longer periods of exposure without risk of sunburn are possible at mid-morning and mid-afternoon. At 3 h from noon, solar zenith angles are almost the same for sites between the tropics and North Patagonia, and at 4 h from noon, for all sites. Then, in these cases, the necessary exposure periods varied slightly between sites, only due to meteorological differences.Fil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vernet, María. University Of California At San Diego; Estados UnidosFil: Paladini, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Fuenzalida, Humberto. Universidad de Chile; ChileFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Booth, Charles R.. Biospherical Instruments Inc.; Estados UnidosFil: Cabrera, Sergio. Universidad de Chile; ChileFil: Casiccia, Claudio. Universidad de Magallanes; ChileFil: Dieguez, Maria del Carmen. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lovengreen, Charlotte. Universidad Austral de Chile; ChileFil: Pedroni, Jorge. Universidad Nacional de la Patagonia; ArgentinaFil: Rosales, Alejandro. Universidad Nacional de la Patagonia; ArgentinaFil: Vrsalovic, Jazmin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Availability of vitamin D photoconversion weighted UV radiation in southern South America

Ultraviolet radiation (UVR) plays a key role in several biological functions, including human health. Skin exposure to UVR is the main factor in vitamin D photoconversion. There is also evidence relating low levels of vitamin D with certain internal cancers, mainly colon, breast and prostate, as well as other diseases. Several epidemiological studies have shown an inverse relationship between the above-mentioned diseases and latitude, in accordance with the ultraviolet radiation latitudinal gradient. The aim of this study is to determine whether UV irradiance levels in the southern South America are sufficient to produce suitable levels of vitamin D year around. For this purpose, vitamin D photoconversion weighted-irradiance was analyzed between S.S. de Jujuy (24.17°S, 65.02°W) and Ushuaia (54° 50′S, 68° 18′W). In addition to irradiance, skin type and area of body exposed to sunlight are critical factors in vitamin D epidemiology. Due to a broad ethnic variability, it was assumed that the skin type in this region varies between II and V (from the most to the less sensitive). All sites except South Patagonia indicate that skin II under any condition of body area exposure and skin V when exposing head, hands, arms and legs, would produce suitable levels of vitamin D year round (except for some days in winter at North Patagonian sites). At South Patagonian sites, minimum healthy levels of vitamin D year round can be reached only by the more sensitive skin II type, if exposing head, hands, arms and legs, which is not a realistic scenario during winter. At these southern latitudes, healthy vitamin D levels would not be obtained between mid May and beginning of August if exposing only the head. Skin V with head exposure is the most critical situation; with the exception of the tropics, sun exposure would not produce suitable levels of vitamin D around winter, during a time period that varies with latitude. Analyzing the best exposure time during the day in order to obtain a suitable level of vitamin D without risk of sunburn, it was concluded that noon is best during winter, as determined previously. For skin type II when exposing head, exposure period in winter varies between 30 and 130 min, according to latitude, except for South Patagonian sites. During summer, noon seems to be a good time of day for short periods of exposure, while during leisure times, longer periods of exposure without risk of sunburn are possible at mid-morning and mid-afternoon. At 3 h from noon, solar zenith angles are almost the same for sites between the tropics and North Patagonia, and at 4 h from noon, for all sites. Then, in these cases, the necessary exposure periods varied slightly between sites, only due to meteorological differences.Fil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vernet, María. University Of California At San Diego; Estados UnidosFil: Paladini, Alejandro Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Fuenzalida, Humberto. Universidad de Chile; ChileFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Booth, Charles R.. Biospherical Instruments Inc.; Estados UnidosFil: Cabrera, Sergio. Universidad de Chile; ChileFil: Casiccia, Claudio. Universidad de Magallanes; ChileFil: Dieguez, Maria del Carmen. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lovengreen, Charlotte. Universidad Austral de Chile; ChileFil: Pedroni, Jorge. Universidad Nacional de la Patagonia; ArgentinaFil: Rosales, Alejandro. Universidad Nacional de la Patagonia; ArgentinaFil: Vrsalovic, Jazmin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin