Mission
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The Atmospheric Optics Group of Valladolid University (GOA-UVa) is involved in the study of atmospheric components, mainly aerosols, with optical methods. The GOA calibration facility is devoted to radiometric calibration of optical instrumentations such as photometers, and it is part of the AERONET-Europe Central Facility, partially funded by the European Union. As a university group, our researchers carry out educational and training activity (graduate, master and PhD thesis). In this site you can find information about the work of the group, members, research lines, publications, projects, vacancies, etc. |
Latests 5 Publications
2021 |
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1. | J C Antuña-Sánchez; R Román; V E Cachorro; C Toledano; C López; R González; D Mateos; A Calle; Á M de Frutos Relative sky radiance from multi-exposure all-sky camera images Journal Article Atmospheric Measurement Techniques, 14 (3), pp. 2201–2217, 2021. @article{amt-14-2201-2021, title = {Relative sky radiance from multi-exposure all-sky camera images}, author = {J C Antuña-Sánchez and R Román and V E Cachorro and C Toledano and C López and R González and D Mateos and A Calle and Á M de Frutos}, url = {https://amt.copernicus.org/articles/14/2201/2021/}, doi = {10.5194/amt-14-2201-2021}, year = {2021}, date = {2021-03-22}, journal = {Atmospheric Measurement Techniques}, volume = {14}, number = {3}, pages = {2201--2217}, abstract = {All-sky cameras are frequently used to detect cloud cover; however, this work explores the use of these instruments for the more complex purpose of extracting relative sky radiances. An all-sky camera (SONA202-NF model) with three colour filters narrower than usual for this kind of cameras is configured to capture raw images at seven exposure times. A detailed camera characterization of the black level, readout noise, hot pixels and linear response is carried out. A methodology is proposed to obtain a linear high dynamic range (HDR) image and its uncertainty, which represents the relative sky radiance (in arbitrary units) maps at three effective wavelengths. The relative sky radiances are extracted from these maps and normalized by dividing every radiance of one channel by the sum of all radiances at this channel. Then, the normalized radiances are compared with the sky radiance measured at different sky points by a sun and sky photometer belonging to the Aerosol Robotic Network (AERONET). The camera radiances correlate with photometer ones except for scattering angles below 10?, which is probably due to some light reflections on the fisheye lens and camera dome. Camera and photometer wavelengths are not coincident; hence, camera radiances are also compared with sky radiances simulated by a radiative transfer model at the same camera effective wavelengths. This comparison reveals an uncertainty on the normalized camera radiances of about 3.3?%, 4.3?% and 5.3?% for 467, 536 and 605?nm, respectively, if specific quality criteria are applied.}, keywords = {}, pubstate = {published}, tppubtype = {article} } All-sky cameras are frequently used to detect cloud cover; however, this work explores the use of these instruments for the more complex purpose of extracting relative sky radiances. An all-sky camera (SONA202-NF model) with three colour filters narrower than usual for this kind of cameras is configured to capture raw images at seven exposure times. A detailed camera characterization of the black level, readout noise, hot pixels and linear response is carried out. A methodology is proposed to obtain a linear high dynamic range (HDR) image and its uncertainty, which represents the relative sky radiance (in arbitrary units) maps at three effective wavelengths. The relative sky radiances are extracted from these maps and normalized by dividing every radiance of one channel by the sum of all radiances at this channel. Then, the normalized radiances are compared with the sky radiance measured at different sky points by a sun and sky photometer belonging to the Aerosol Robotic Network (AERONET). The camera radiances correlate with photometer ones except for scattering angles below 10?, which is probably due to some light reflections on the fisheye lens and camera dome. Camera and photometer wavelengths are not coincident; hence, camera radiances are also compared with sky radiances simulated by a radiative transfer model at the same camera effective wavelengths. This comparison reveals an uncertainty on the normalized camera radiances of about 3.3?%, 4.3?% and 5.3?% for 467, 536 and 605?nm, respectively, if specific quality criteria are applied. |
2. | Ana Barroso; Sandra Mogo; Manuela M V G Silva; Victoria Cachorro; Ángel de Frutos Morphology, Mineralogy, and Chemistry of Atmospheric Aerosols Nearby an Active Mining Area: Aljustrel Mine (SW Portugal) Journal Article Atmosphere, 12 (3), 2021, ISSN: 2073-4433. @article{atmos12030333, title = {Morphology, Mineralogy, and Chemistry of Atmospheric Aerosols Nearby an Active Mining Area: Aljustrel Mine (SW Portugal)}, author = {Ana Barroso and Sandra Mogo and Manuela M V G Silva and Victoria Cachorro and Ángel de Frutos}, url = {https://www.mdpi.com/2073-4433/12/3/333}, doi = {10.3390/atmos12030333}, issn = {2073-4433}, year = {2021}, date = {2021-03-05}, journal = {Atmosphere}, volume = {12}, number = {3}, abstract = {Mining activities increase contaminant levels in the environment, so it is crucial to study the particulate matter in these areas to understand the impacts on nearby urban areas and populations. This work was conducted close to the active mine of Aljustrel (Portugal), where black dust deposition is evident. PM10 samples were collected in two periods: 10–17 July and 1–10 November of 2018. Two different techniques were used: SEM-EDX for the individual characterization of the aerosols and ICP-MS to quantify the elemental concentration of 11 elements (Ca, Na, Fe, Mn, As, Cd, Cu, Sb, Pb, and Zn). In this region, the observed PM10 mass concentration was 20 to 47 µg m ?3 (July) and 4 to 23 µg m?3 (November), which is lower than the limit of 50 ?g m?3 established in the European Directive. The individual characterization of 2006 particles by SEM-EDX shows oxides (17%) and sulfides (10%), while Na, Si, Fe, S, Al, and Cu are the elements with the most representativeness in all the analyzed particles. The ICP-MS results indicate that the daily elemental concentration in the samples collected in July is higher than November, and only As exceeds the limit established for European legislation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Mining activities increase contaminant levels in the environment, so it is crucial to study the particulate matter in these areas to understand the impacts on nearby urban areas and populations. This work was conducted close to the active mine of Aljustrel (Portugal), where black dust deposition is evident. PM10 samples were collected in two periods: 10–17 July and 1–10 November of 2018. Two different techniques were used: SEM-EDX for the individual characterization of the aerosols and ICP-MS to quantify the elemental concentration of 11 elements (Ca, Na, Fe, Mn, As, Cd, Cu, Sb, Pb, and Zn). In this region, the observed PM10 mass concentration was 20 to 47 µg m ?3 (July) and 4 to 23 µg m?3 (November), which is lower than the limit of 50 ?g m?3 established in the European Directive. The individual characterization of 2006 particles by SEM-EDX shows oxides (17%) and sulfides (10%), while Na, Si, Fe, S, Al, and Cu are the elements with the most representativeness in all the analyzed particles. The ICP-MS results indicate that the daily elemental concentration in the samples collected in July is higher than November, and only As exceeds the limit established for European legislation. |
3. | AE Bedoya-Velásquez; M Herreras-Giralda; R Román; M Wiegner; S Lefebvre; C Toledano; T Huet; R Ceolato Ceilometer inversion method using water-vapor correction from co-located microwave radiometer for aerosol retrievals Journal Article Atmospheric Research, pp. 105379, 2021. @article{bedoya2021ceilometer, title = {Ceilometer inversion method using water-vapor correction from co-located microwave radiometer for aerosol retrievals}, author = {AE Bedoya-Velásquez and M Herreras-Giralda and R Román and M Wiegner and S Lefebvre and C Toledano and T Huet and R Ceolato}, doi = {10.1016/j.atmosres.2020.105379}, year = {2021}, date = {2021-03-01}, journal = {Atmospheric Research}, pages = {105379}, publisher = {Elsevier}, abstract = {Recent ceilometer models are more sensitive to aerosols, which is increasing the interest in these instruments to retrieve aerosol optical and microphysical properties. In this paper, a new methodology is proposed to retrieve aerosol vertical extinction and backscatter profiles from a Vaisala ceilometer CL51 model. This methodology is based in two parts: first, a signal pre-processing with a suppression of the dark current and background noises, and a correction of the water vapor absorption using near-real-time temperature and absolute humidity (AH) profiles from a co-located Microwave radiometer (MWR). The measured dark current shows a height-dependence from 11?km agl to the end of the profile. From the water vapor correction, it was seen that the raw ceilometer signal overestimates the water vapor corrected one, mainly below 1?km agl. Second part is based on an iterative Klett-based algorithm making use of AERONET (AErosol RObotic NETwork) AOD (Aerosol Optical Depth) and ceilometer profiles as inputs to retrieve the extinction and backscatter profiles. The sensitivity of the aerosol retrievals to the use of modelled temperature and absolute humidity from HYSPLIT to correct water vapor absorption, instead of MWR measurements, is studied. The absolute errors found in temperature and AH profiles leads to errors in the pre-processed range corrected signals up to 9%, and then in particle backscatter (?p) and particle extinction (?p) coefficients up to 2.2 % and 25 %, respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recent ceilometer models are more sensitive to aerosols, which is increasing the interest in these instruments to retrieve aerosol optical and microphysical properties. In this paper, a new methodology is proposed to retrieve aerosol vertical extinction and backscatter profiles from a Vaisala ceilometer CL51 model. This methodology is based in two parts: first, a signal pre-processing with a suppression of the dark current and background noises, and a correction of the water vapor absorption using near-real-time temperature and absolute humidity (AH) profiles from a co-located Microwave radiometer (MWR). The measured dark current shows a height-dependence from 11?km agl to the end of the profile. From the water vapor correction, it was seen that the raw ceilometer signal overestimates the water vapor corrected one, mainly below 1?km agl. Second part is based on an iterative Klett-based algorithm making use of AERONET (AErosol RObotic NETwork) AOD (Aerosol Optical Depth) and ceilometer profiles as inputs to retrieve the extinction and backscatter profiles. The sensitivity of the aerosol retrievals to the use of modelled temperature and absolute humidity from HYSPLIT to correct water vapor absorption, instead of MWR measurements, is studied. The absolute errors found in temperature and AH profiles leads to errors in the pre-processed range corrected signals up to 9%, and then in particle backscatter (?p) and particle extinction (?p) coefficients up to 2.2 % and 25 %, respectively. |
4. | Ramiro González Desarrollo de nuevos métodos de procesado de datos de redes fotométricas para el análisis de propiedades del aerosol atmosférico PhD Thesis Universidad de Valladolid, 2021, (dirección: Carlos Toledano, Roberto Román). @phdthesis{Gonzalez2021, title = {Desarrollo de nuevos métodos de procesado de datos de redes fotométricas para el análisis de propiedades del aerosol atmosférico}, author = {Ramiro González}, year = {2021}, date = {2021-01-14}, address = {Valladolid, Spain}, school = {Universidad de Valladolid}, abstract = {Se define como aerosol atmosférico a aquellas partículas que se encuentran suspendidas en la atmósfera en estado sólido o líquido. El estudio y análisis de los aerosoles son de vital impor- tancia debido a que estos afectan al clima, a la actividad humana y a la salud de las personas. Distintas redes operan de forma rutinaria y con un grado mayor o menor de automatización con el objetivo de obtener medidas y productos de aerosoles para su posterior análisis. Las medidas ópticas o de detección remota, como las que proporcionan los fotómetros desde tierra y muchos sensores de satélite, basan su funcionamiento en la interacción de la luz con los aerosoles. Uno de los principales productos de estas redes es el espesor óptico de aerosoles (AOD del inglés Ae- rosol Optical Depth). Normalmente se obtiene el AOD midiendo con un fotómetro la irradiancia directa del Sol que llega a la superficie terrestre, ya que la cantidad de irradiancia directa solar extinguida durante su paso por la atmósfera terrestre depende del AOD a través de la ley de Beer- Bouguer-Lambert. El AOD está relacionado con la cantidad de aerosoles presentes en la columna atmosférica, y su variación espectral ligada al tamaño predominante de las partículas. Recientes avances y mejoras en los instrumentos de medida fotométrica han permitido adaptar las medidas directas al Sol también a la Luna, pudiendo obtener valores de AOD también durante la noche. Esto permite que en aquellas zonas con largos periodos nocturnos, principalmente en las zonas polares, se pueda de igual manera obtener información relacionada con los aerosoles. Esto ayuda a rellenar huecos muy relevantes en las series de datos obtenidas en estas zonas, que hasta ahora contaban tan solo con fotometría solar. En este trabajo se aborda el análisis de las propiedades del aerosol atmosférico a través de la creación y mejora de nuevos procesados y productos. En concreto se presenta el desarrollo de nuevos métodos para el cálculo operacional del AOD en una red de instrumentos, tanto para el día como para la noche. En primer lugar, se ha desarrollado el cálculo del AOD durante el día describiendo paso a paso su proceso y datos utilizados. En una segunda instancia se ha adaptado este cálculo a la noche, describiendo de igual manera los modelos utilizados y desarrollando una nueva corrección sobre estos, la cual se propone para la mejora en el cálculo del AOD por la noche. Los productos obtenidos mediante ambos métodos se han contrastado con series de datos independientes y de referencia, que nos ha permitido asegurar la calidad del algoritmo. Finalmente, la puesta en producción de ambos productos en el sistema CÆLIS ha permitido de- tectar un evento de aerosoles extremadamente anómalo en una de las estaciones que el Grupo de Óptica Atmosférica de la Universidad de Valladolid opera en la estación de Marambio, en la Antártida. Con la ayuda de otras medidas complementarias y algunos modelos atmosféricos, se ha descubierto que los aerosoles procedían de la quema de biomasa generada por incendios localizados en el Este de Australia a finales de 2019. La detección de este evento pone de mani- fiesto la importancia y el valor de disponer de medidas rutinarias, procesamientos automatizados y productos de calidad que permitan analizar las propiedades del aerosol atmosférico.}, note = {dirección: Carlos Toledano, Roberto Román}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Se define como aerosol atmosférico a aquellas partículas que se encuentran suspendidas en la atmósfera en estado sólido o líquido. El estudio y análisis de los aerosoles son de vital impor- tancia debido a que estos afectan al clima, a la actividad humana y a la salud de las personas. Distintas redes operan de forma rutinaria y con un grado mayor o menor de automatización con el objetivo de obtener medidas y productos de aerosoles para su posterior análisis. Las medidas ópticas o de detección remota, como las que proporcionan los fotómetros desde tierra y muchos sensores de satélite, basan su funcionamiento en la interacción de la luz con los aerosoles. Uno de los principales productos de estas redes es el espesor óptico de aerosoles (AOD del inglés Ae- rosol Optical Depth). Normalmente se obtiene el AOD midiendo con un fotómetro la irradiancia directa del Sol que llega a la superficie terrestre, ya que la cantidad de irradiancia directa solar extinguida durante su paso por la atmósfera terrestre depende del AOD a través de la ley de Beer- Bouguer-Lambert. El AOD está relacionado con la cantidad de aerosoles presentes en la columna atmosférica, y su variación espectral ligada al tamaño predominante de las partículas. Recientes avances y mejoras en los instrumentos de medida fotométrica han permitido adaptar las medidas directas al Sol también a la Luna, pudiendo obtener valores de AOD también durante la noche. Esto permite que en aquellas zonas con largos periodos nocturnos, principalmente en las zonas polares, se pueda de igual manera obtener información relacionada con los aerosoles. Esto ayuda a rellenar huecos muy relevantes en las series de datos obtenidas en estas zonas, que hasta ahora contaban tan solo con fotometría solar. En este trabajo se aborda el análisis de las propiedades del aerosol atmosférico a través de la creación y mejora de nuevos procesados y productos. En concreto se presenta el desarrollo de nuevos métodos para el cálculo operacional del AOD en una red de instrumentos, tanto para el día como para la noche. En primer lugar, se ha desarrollado el cálculo del AOD durante el día describiendo paso a paso su proceso y datos utilizados. En una segunda instancia se ha adaptado este cálculo a la noche, describiendo de igual manera los modelos utilizados y desarrollando una nueva corrección sobre estos, la cual se propone para la mejora en el cálculo del AOD por la noche. Los productos obtenidos mediante ambos métodos se han contrastado con series de datos independientes y de referencia, que nos ha permitido asegurar la calidad del algoritmo. Finalmente, la puesta en producción de ambos productos en el sistema CÆLIS ha permitido de- tectar un evento de aerosoles extremadamente anómalo en una de las estaciones que el Grupo de Óptica Atmosférica de la Universidad de Valladolid opera en la estación de Marambio, en la Antártida. Con la ayuda de otras medidas complementarias y algunos modelos atmosféricos, se ha descubierto que los aerosoles procedían de la quema de biomasa generada por incendios localizados en el Este de Australia a finales de 2019. La detección de este evento pone de mani- fiesto la importancia y el valor de disponer de medidas rutinarias, procesamientos automatizados y productos de calidad que permitan analizar las propiedades del aerosol atmosférico. |
5. | Juan Carlos Antuña-Sánchez; René Estevan; Roberto Román; Juan Carlos Antuña-Marrero; Victoria E Cachorro; Albeth Rodríguez Vega; Ángel M de Frutos Solar Radiation Climatology in Camagüey, Cuba (1981–2016) Journal Article Remote Sensing, 13 (2), 2021, ISSN: 2072-4292. @article{rs13020169, title = {Solar Radiation Climatology in Camagüey, Cuba (1981–2016)}, author = {Juan Carlos Antuña-Sánchez and René Estevan and Roberto Román and Juan Carlos Antuña-Marrero and Victoria E Cachorro and Albeth Rodríguez Vega and Ángel M de Frutos}, url = {https://www.mdpi.com/2072-4292/13/2/169}, doi = {10.3390/rs13020169}, issn = {2072-4292}, year = {2021}, date = {2021-01-01}, journal = {Remote Sensing}, volume = {13}, number = {2}, abstract = {The transition to renewable energies is an unavoidable step to guarantee a peaceful and sustainable future for humankind. Although solar radiation is one of the main sources of renewable energy, there are broad regions of the planet where it has not been characterized appropriately to provide the necessary information for regional and local planning and design of the different solar powered systems. The Caribbean, and Cuba in particular, lacked until very recently at least one long-term series of surface solar radiation measurements. Here we present the first long-term records of solar radiation for this region. Solar radiation measurements manually conducted and recorded on paper were rescued, reprocessed and quality controlled to develop the solar radiation climatology at the Actinometrical Station of Camagüey, in Cuba (21.422°N; 77.850°W; 122 m a.s.l.) for the period 1981–2016. The diurnal cycle based on the average hourly values of the global, direct and diffuse horizontal variables for the entire period have been determined and analyzed showing the dependence on solar zenith angle (SZA) and clouds. The annual cycle of global solar component given by the mean monthly daily values presents two maxima, one in April and another one in July with values of 5.06 and 4.91 kWh m−2, respectively (18.23 and 17.67 MJ m−2 per day for insolation), and the minimum in December (3.15 kWh m−2 or 11.33 MJ m−2). The maxima are governed by the direct solar components and are modulated by cloudiness. Both, diurnal and annual cycles of the diffuse solar component show a smoothed bell shaped behavior. In general solar radiation at this station presents a strong influence of clouds, with little seasonal variation but with higher values during the rainy season. Daily global radiation annual averages showed its maximum value in the year 1983, with 17.45 MJ m−2 explained by very low cloudiness this year, and the minimum value was reported in 2009 with a value of 12.43 MJ m−2 that could not explained by the cloud coverage or the aerosols optical depths registered that year. The effects of the 1982 El Chichón and 1991 Mount Pinatubo volcanic eruptions on the solar radiation variables at Camagüey are also shown and discussed. The results achieved in this study shown the characteristics of solar radiation in this area and their potential for solar power applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The transition to renewable energies is an unavoidable step to guarantee a peaceful and sustainable future for humankind. Although solar radiation is one of the main sources of renewable energy, there are broad regions of the planet where it has not been characterized appropriately to provide the necessary information for regional and local planning and design of the different solar powered systems. The Caribbean, and Cuba in particular, lacked until very recently at least one long-term series of surface solar radiation measurements. Here we present the first long-term records of solar radiation for this region. Solar radiation measurements manually conducted and recorded on paper were rescued, reprocessed and quality controlled to develop the solar radiation climatology at the Actinometrical Station of Camagüey, in Cuba (21.422°N; 77.850°W; 122 m a.s.l.) for the period 1981–2016. The diurnal cycle based on the average hourly values of the global, direct and diffuse horizontal variables for the entire period have been determined and analyzed showing the dependence on solar zenith angle (SZA) and clouds. The annual cycle of global solar component given by the mean monthly daily values presents two maxima, one in April and another one in July with values of 5.06 and 4.91 kWh m−2, respectively (18.23 and 17.67 MJ m−2 per day for insolation), and the minimum in December (3.15 kWh m−2 or 11.33 MJ m−2). The maxima are governed by the direct solar components and are modulated by cloudiness. Both, diurnal and annual cycles of the diffuse solar component show a smoothed bell shaped behavior. In general solar radiation at this station presents a strong influence of clouds, with little seasonal variation but with higher values during the rainy season. Daily global radiation annual averages showed its maximum value in the year 1983, with 17.45 MJ m−2 explained by very low cloudiness this year, and the minimum value was reported in 2009 with a value of 12.43 MJ m−2 that could not explained by the cloud coverage or the aerosols optical depths registered that year. The effects of the 1982 El Chichón and 1991 Mount Pinatubo volcanic eruptions on the solar radiation variables at Camagüey are also shown and discussed. The results achieved in this study shown the characteristics of solar radiation in this area and their potential for solar power applications. |