Mission
 |
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
2022
11.
García, O.; Suárez, D.; Cuevas, E.; Ramos, R.; Barreto, Á.; Hernández, M.; Quintero, V.; Toledano, C.; Sicard, M.; Córdoba-Jabonero, C.; Riz, V.; Roininen, R.; López, C.; Vilches, J.; Weiss, M.; Carreño, V.; Taquet, N.; Boulesteix, T.; Fraile, E.; Torres, C.; Prats, N.; Alcántara, A.; León, S.; Rivas, P.; Álvarez, Ó.; Parra, F.; de Luis, J.; González, C.; Armas, C.; Romero, P.; de Bustos, J.; Redondas, A.; Marrero, C.; Milford, C.; Román, R.; González, R.; López-Cayuela, M.; Carvajal-Pérez, C.; Chinea, N.; García, R.; Almansa, F.; González, Y.; Bullón, F.; Poggio, M.; Rivera, C.; Bayo, C.; Rey, F.
La erupción volcánica de La Palma y el papel de la Agencia Estatal de Meteorología Journal Article
In: Revista Tiempo Y Clima, vol. 5, no. 76, 2022.
@article{García2022,
title = {La erupción volcánica de La Palma y el papel de la Agencia Estatal de Meteorología},
author = {García, O. and Suárez, D. and Cuevas, E. and Ramos, R. and Barreto, Á. and Hernández, M. and Quintero, V. and Toledano, C. and Sicard, M. and Córdoba-Jabonero, C. and Riz, V. and Roininen, R. and López, C. and Vilches, J. and Weiss, M. and Carreño, V. and Taquet, N. and Boulesteix, T. and Fraile, E. and Torres, C. and Prats, N. and Alcántara, A. and León, S. and Rivas, P. and Álvarez, Ó. and Parra, F. and de Luis, J. and González, C. and Armas, C. and Romero, P. and de Bustos, J. and Redondas, A. and Marrero, C. and Milford, C. and Román, R. and González, R. and López-Cayuela, M. and Carvajal-Pérez, C. and Chinea, N. and García, R. and Almansa, F. and González, Y. and Bullón, F. and Poggio, M. and Rivera, C. and Bayo, C. and Rey, F.},
url = {https://pub.ame-web.org/index.php/TyC/article/view/2516},
year = {2022},
date = {2022-05-04},
journal = { Revista Tiempo Y Clima},
volume = {5},
number = {76},
abstract = {Durante la erupción del volcán de Cumbre Vieja, en la isla de La Palma en 2021, la Agencia Estatal de Meteorología (AEMET), en calidad de Servicio Nacional y Autoridad Meteorológica del Estado, prestó diferentes servicios de apoyo al Comité Científico y al Comité Asesor del Plan de Emergencias Volcánicas de Canarias (PEVOLCA). Parte de sus actividades abarcaron la vigilancia y predicción meteorológica, la monitorización y predicción del transporte del penacho volcánico, y la valoración del impacto de las emisiones de gases y cenizas de la erupción volcánica en la calidad del aire en la isla de La Palma y en la región de Canarias.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Durante la erupción del volcán de Cumbre Vieja, en la isla de La Palma en 2021, la Agencia Estatal de Meteorología (AEMET), en calidad de Servicio Nacional y Autoridad Meteorológica del Estado, prestó diferentes servicios de apoyo al Comité Científico y al Comité Asesor del Plan de Emergencias Volcánicas de Canarias (PEVOLCA). Parte de sus actividades abarcaron la vigilancia y predicción meteorológica, la monitorización y predicción del transporte del penacho volcánico, y la valoración del impacto de las emisiones de gases y cenizas de la erupción volcánica en la calidad del aire en la isla de La Palma y en la región de Canarias.
12.
J.C. Antuña-Sánchez; R. Román; J.L. Bosch; C. Toledano; D. Mateos; R. González; V.E. Cachorro; Ángel de Frutos
ORION software tool for the geometrical calibration of all-sky cameras Journal Article
In: PLoS ONE 17(3), 2022.
@article{Antuña-Sánchez2022,
title = {ORION software tool for the geometrical calibration of all-sky cameras},
author = {J.C. Antuña-Sánchez and R. Román and J.L. Bosch and C. Toledano and D. Mateos and R. González and V.E. Cachorro and Ángel de Frutos},
doi = {10.1371/journal.pone.0265959},
year = {2022},
date = {2022-03-31},
urldate = {2022-03-31},
journal = {PLoS ONE 17(3)},
abstract = {This paper presents the software application ORION (All-sky camera geOmetry calibRation from star positIONs). This software has been developed with the aim of providing geometrical calibration to all-sky cameras, i.e. assess which sky coordinates (zenith and azimuth angles) correspond to each camera pixel. It is useful to locate bodies over the celestial vault, like stars and planets, in the camera images. The user needs to feed ORION with a set of cloud-free sky images captured at night-time for obtaining the calibration matrices. ORION searches the position of various stars in the sky images. This search can be automatic or manual. The sky coordinates of the stars and the corresponding pixel positions in the camera images are used together to determine the calibration matrices. The calibration is based on three parameters: the pixel position of the sky zenith in the image; the shift angle of the azimuth viewed by the camera with respect to the real North; and the relationship between the sky zenith angle and the pixel radial distance regards to the sky zenith in the image. In addition, ORION includes other features to facilitate its use, such as the check of the accuracy of the calibration. An example of ORION application is shown, obtaining the calibration matrices for a set of images and studying the accuracy of the calibration to predict a star position. Accuracy is about 9.0 arcmin for the analyzed example using a camera with average resolution of 5.4 arcmin/pixel (about 1.7 pixels).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper presents the software application ORION (All-sky camera geOmetry calibRation from star positIONs). This software has been developed with the aim of providing geometrical calibration to all-sky cameras, i.e. assess which sky coordinates (zenith and azimuth angles) correspond to each camera pixel. It is useful to locate bodies over the celestial vault, like stars and planets, in the camera images. The user needs to feed ORION with a set of cloud-free sky images captured at night-time for obtaining the calibration matrices. ORION searches the position of various stars in the sky images. This search can be automatic or manual. The sky coordinates of the stars and the corresponding pixel positions in the camera images are used together to determine the calibration matrices. The calibration is based on three parameters: the pixel position of the sky zenith in the image; the shift angle of the azimuth viewed by the camera with respect to the real North; and the relationship between the sky zenith angle and the pixel radial distance regards to the sky zenith in the image. In addition, ORION includes other features to facilitate its use, such as the check of the accuracy of the calibration. An example of ORION application is shown, obtaining the calibration matrices for a set of images and studying the accuracy of the calibration to predict a star position. Accuracy is about 9.0 arcmin for the analyzed example using a camera with average resolution of 5.4 arcmin/pixel (about 1.7 pixels).
13.
V. E. Cachorro; J. C. Antuña-Sanchez; Á. M. Frutos
SSolar-GOA v1.0: a simple, fast, and accurate Spectral SOLAR radiative transfer model for clear skies Journal Article
In: Geoscientific Model Development, vol. 15, no. 4, pp. 1689–1712, 2022.
@article{Cachorro2022,
title = {SSolar-GOA v1.0: a simple, fast, and accurate Spectral SOLAR radiative transfer model for clear skies},
author = {V. E. Cachorro and J. C. Antuña-Sanchez and Á. M. Frutos},
url = {https://gmd.copernicus.org/articles/15/1689/2022/},
doi = {10.5194/gmd-15-1689-2022},
year = {2022},
date = {2022-02-25},
urldate = {2022-02-25},
journal = {Geoscientific Model Development},
volume = {15},
number = {4},
pages = {1689--1712},
abstract = {The aim of this work is to describe the features of and to validate a simple, fast, accurate, and physically based spectral radiative transfer model in the solar wavelength range under clear skies. The model, named SSolar-GOA (the first “S” stands for “spectral”), was developed to evaluate the instantaneous values of spectral solar irradiances at ground level or at a given altitude of the atmosphere. The model requirements are designed based on the simplicity of the analytical expressions for the transmittance functions in order to be easily replicated and applied by a wide community of users for many different applications (atmospheric and environmental research studies, satellite remote sensing, solar energy, agronomy and forestry, ecology, and others). Although spectral, the model runs quickly and has sufficient accuracy for the evaluation of solar irradiances with a spectral resolution of 1–10?nm. The model assumes a single mixed molecule–aerosol scattering layer where the original Ambartsumian method of “adding layers” in a one-dimensional medium is applied, obtaining a parameterized expression for the total transmittance of scattering. Absorption by the different atmospheric gases follows “band model” parameterized expressions. The input parameters must be realistic and easily available since the spectral aerosol optical depth (AOD) is the main driver of the model. The validation of the SSolar-GOA model has been carried out through comparison with simulated irradiance data from the libRadtran package and with direct and global spectra measured by spectroradiometers. Thousands of spectra under clear skies have been compared for different atmospheric conditions and solar zenith angles (SZA). The SSolar-GOA is validated by a quantitative comparison with libRadtran, showing that it underestimates direct normal, global, and diffuse spectral components with relative differences of +1?% (RMSE?%?=?4.6–8), +3?% (RMSE?%?=?5.3–8), and 8?% (RMSE?%?=?9.3–9.6), respectively, when the SZA varies from 6 to 60?. Compared with the measured irradiance data of the LI-1800 and ASD spectroradiometers, the relative differences of direct normal and global components are within the overall experimental error, about ±2?%–12?% (RMSE?%?=?5–8.3), with underestimated or overestimated values. The diffuse component presents the highest degree of relative difference that can reach ±20?%–30?% and RMSE of 25?%–50?%. The relative differences depend strongly on the spectral solar region analysed and the SZA, but the high values of RMSE are due to the artifice generated by the different spectral resolution of the absorption coefficients of both models. Model approach errors combined with calibration instrument errors may explain the observed differences. The SSolar-GOA v1.0 is implemented in Python and open-source licensing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The aim of this work is to describe the features of and to validate a simple, fast, accurate, and physically based spectral radiative transfer model in the solar wavelength range under clear skies. The model, named SSolar-GOA (the first “S” stands for “spectral”), was developed to evaluate the instantaneous values of spectral solar irradiances at ground level or at a given altitude of the atmosphere. The model requirements are designed based on the simplicity of the analytical expressions for the transmittance functions in order to be easily replicated and applied by a wide community of users for many different applications (atmospheric and environmental research studies, satellite remote sensing, solar energy, agronomy and forestry, ecology, and others). Although spectral, the model runs quickly and has sufficient accuracy for the evaluation of solar irradiances with a spectral resolution of 1–10?nm. The model assumes a single mixed molecule–aerosol scattering layer where the original Ambartsumian method of “adding layers” in a one-dimensional medium is applied, obtaining a parameterized expression for the total transmittance of scattering. Absorption by the different atmospheric gases follows “band model” parameterized expressions. The input parameters must be realistic and easily available since the spectral aerosol optical depth (AOD) is the main driver of the model. The validation of the SSolar-GOA model has been carried out through comparison with simulated irradiance data from the libRadtran package and with direct and global spectra measured by spectroradiometers. Thousands of spectra under clear skies have been compared for different atmospheric conditions and solar zenith angles (SZA). The SSolar-GOA is validated by a quantitative comparison with libRadtran, showing that it underestimates direct normal, global, and diffuse spectral components with relative differences of +1?% (RMSE?%?=?4.6–8), +3?% (RMSE?%?=?5.3–8), and 8?% (RMSE?%?=?9.3–9.6), respectively, when the SZA varies from 6 to 60?. Compared with the measured irradiance data of the LI-1800 and ASD spectroradiometers, the relative differences of direct normal and global components are within the overall experimental error, about ±2?%–12?% (RMSE?%?=?5–8.3), with underestimated or overestimated values. The diffuse component presents the highest degree of relative difference that can reach ±20?%–30?% and RMSE of 25?%–50?%. The relative differences depend strongly on the spectral solar region analysed and the SZA, but the high values of RMSE are due to the artifice generated by the different spectral resolution of the absorption coefficients of both models. Model approach errors combined with calibration instrument errors may explain the observed differences. The SSolar-GOA v1.0 is implemented in Python and open-source licensing.
14.
Juan Carlos Antuña-Marrero; Roberto Román; Victoria E. Cachorro; David Mateos; Carlos Toledano; Abel Calle; Juan Carlos Antuña-Sánchez; Javier Vaquero-Martínez; Manuel Antón; Ángel M. Frutos Baraja
Integrated water vapor over the Arctic: Comparison between radiosondes and sun photometer observations Journal Article
In: Atmospheric Research, vol. 270, pp. 106059, 2022, ISSN: 0169-8095.
@article{Antuña-Marrero2022,
title = {Integrated water vapor over the Arctic: Comparison between radiosondes and sun photometer observations},
author = {Juan Carlos Antuña-Marrero and Roberto Román and Victoria E. Cachorro and David Mateos and Carlos Toledano and Abel Calle and Juan Carlos Antuña-Sánchez and Javier Vaquero-Martínez and Manuel Antón and Ángel M. Frutos Baraja},
url = {https://www.sciencedirect.com/science/article/pii/S016980952200045X},
doi = {https://doi.org/10.1016/j.atmosres.2022.106059},
issn = {0169-8095},
year = {2022},
date = {2022-02-02},
urldate = {2022-01-01},
journal = {Atmospheric Research},
volume = {270},
pages = {106059},
abstract = {The amplification of global warming because of the feedbacks associated with the increase in atmospheric moisture and the decrease in sea ice and snow cover in the Arctic is currently the focus of scientists, policy makers and society. The amplification of global warming is the response to increases in precipitation originally caused by climate change. Arctic predominant increases in specific humidity and precipitation have been documented by observations. In comparison, evapotranspiration in the Arctic is poorly known, in part, because the spatial and temporal sparsity of accurate in situ and remote sensing observations. Although more than 20 observations sites in the Arctic are available, where AERONET sun photometer integrated water vapor (IWV) measurements have been conducted, that information have been barely used. Here, we present a comparison of IWV observations from radiosondes and AERONET sun photometers at ten sites located across the Arctic with the goal to document the feasibility of that set of observations to contribute to the ongoing and future research on polar regions. Sun photometer IWV observations are averaged for three-time windows; 30 min, 6 and 24 h. The predominant dry bias of AERONET IWV observations with respect to radiosondes, identified at tropical and midlatitudes, is also present in the Arctic. The statistics of the comparison show robust results at eight of the ten sites, with precision and accuracy magnitudes below 8 and 2% respectively. The possible causes of the less robust results at the other two sites are discussed. In addition, the impact of selecting other temporal coincidence windows in the average sun photometer IWV used in the comparison were tested. Auto-correlation in diurnal sun photometer IWV could produce appreciable bias in the statistics used for the comparison. We suggest using only one pair of values per day, consisting in the daily mean IWV sun photometer and the IWV radiosonde observation value. This feature should be valid also for comparison of IWV from sun photometer and other instruments. Maximum 10% error level of IWV from sun photometer observations, when compared with radiosondes, have been found for the Arctic. It is in the same order of magnitude than at tropical and middle latitudes locations. It has been demonstrated the feasibility of AERONET IWV observations in the Arctic for research on this variable. AERONET standard instruments and its centralized-standard processing algorithm allow its IWV observations to be considered a relative standard dataset for the re-calibration of other instrumental IWV observations assuming radiosondes as the absolute standard dataset.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The amplification of global warming because of the feedbacks associated with the increase in atmospheric moisture and the decrease in sea ice and snow cover in the Arctic is currently the focus of scientists, policy makers and society. The amplification of global warming is the response to increases in precipitation originally caused by climate change. Arctic predominant increases in specific humidity and precipitation have been documented by observations. In comparison, evapotranspiration in the Arctic is poorly known, in part, because the spatial and temporal sparsity of accurate in situ and remote sensing observations. Although more than 20 observations sites in the Arctic are available, where AERONET sun photometer integrated water vapor (IWV) measurements have been conducted, that information have been barely used. Here, we present a comparison of IWV observations from radiosondes and AERONET sun photometers at ten sites located across the Arctic with the goal to document the feasibility of that set of observations to contribute to the ongoing and future research on polar regions. Sun photometer IWV observations are averaged for three-time windows; 30 min, 6 and 24 h. The predominant dry bias of AERONET IWV observations with respect to radiosondes, identified at tropical and midlatitudes, is also present in the Arctic. The statistics of the comparison show robust results at eight of the ten sites, with precision and accuracy magnitudes below 8 and 2% respectively. The possible causes of the less robust results at the other two sites are discussed. In addition, the impact of selecting other temporal coincidence windows in the average sun photometer IWV used in the comparison were tested. Auto-correlation in diurnal sun photometer IWV could produce appreciable bias in the statistics used for the comparison. We suggest using only one pair of values per day, consisting in the daily mean IWV sun photometer and the IWV radiosonde observation value. This feature should be valid also for comparison of IWV from sun photometer and other instruments. Maximum 10% error level of IWV from sun photometer observations, when compared with radiosondes, have been found for the Arctic. It is in the same order of magnitude than at tropical and middle latitudes locations. It has been demonstrated the feasibility of AERONET IWV observations in the Arctic for research on this variable. AERONET standard instruments and its centralized-standard processing algorithm allow its IWV observations to be considered a relative standard dataset for the re-calibration of other instrumental IWV observations assuming radiosondes as the absolute standard dataset.
15.
R. Román; J. C. Antuña-Sánchez; V. E. Cachorro; C. Toledano; B. Torres; D. Mateos; D. Fuertes; C. López; R. González; T. Lapionok; M. Herreras-Giralda; O. Dubovik; Á. M. Frutos
Retrieval of aerosol properties using relative radiance measurements from an all-sky camera Journal Article
In: Atmospheric Measurement Techniques, vol. 15, no. 2, pp. 407–433, 2022.
@article{Román2022,
title = {Retrieval of aerosol properties using relative radiance measurements from an all-sky camera},
author = {R. Román and J. C. Antuña-Sánchez and V. E. Cachorro and C. Toledano and B. Torres and D. Mateos and D. Fuertes and C. López and R. González and T. Lapionok and M. Herreras-Giralda and O. Dubovik and Á. M. Frutos},
url = {https://amt.copernicus.org/articles/15/407/2022/},
doi = {10.5194/amt-15-407-2022},
year = {2022},
date = {2022-01-27},
urldate = {2022-01-01},
journal = {Atmospheric Measurement Techniques},
volume = {15},
number = {2},
pages = {407--433},
abstract = {This paper explores the potential of all-sky cameras to retrieve aerosol properties with the GRASP code (Generalized Retrieval of Atmosphere and Surface Properties). To this end, normalized sky radiances (NSRs) extracted from an all-sky camera at three effective wavelengths (467, 536 and 605?nm) are used in this study. NSR observations are a set of relative (uncalibrated) sky radiances in arbitrary units. NSR observations have been simulated for different aerosol loads and types with the forward radiative transfer module of GRASP, indicating that NSR observations contain information about the aerosol type, as well as about the aerosol optical depth (AOD), at least for low and moderate aerosol loads. An additional sensitivity study with synthetic data has been carried out to quantify the theoretical accuracy and precision of the aerosol properties (AOD, size distribution parameters, etc.) retrieved by GRASP using NSR observations as input. As a result, the theoretical accuracy of AOD is within ±0.02 for AOD values lower than or equal to 0.4, while the theoretical precision goes from 0.01 to 0.05 when AOD at 467?nm varies from 0.1 to 0.5. NSR measurements recorded at Valladolid (Spain) with an all-sky camera for more than 2 years have been inverted with GRASP. The retrieved aerosol properties are compared with independent values provided by co-located AERONET (AErosol RObotic NETwork) measurements. AODs from both data sets correlate with determination coefficient (r2) values of about 0.87. Finally, the novel multi-pixel approach of GRASP is applied to daily camera radiances together by constraining the temporal variation in certain aerosol properties. This temporal linkage (multi-pixel approach) provides promising results, reducing the highly temporal variation in some aerosol properties retrieved with the standard (one by one or single-pixel) approach. This work implies an advance in the use of all-sky cameras for the retrieval of aerosol properties.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This paper explores the potential of all-sky cameras to retrieve aerosol properties with the GRASP code (Generalized Retrieval of Atmosphere and Surface Properties). To this end, normalized sky radiances (NSRs) extracted from an all-sky camera at three effective wavelengths (467, 536 and 605?nm) are used in this study. NSR observations are a set of relative (uncalibrated) sky radiances in arbitrary units. NSR observations have been simulated for different aerosol loads and types with the forward radiative transfer module of GRASP, indicating that NSR observations contain information about the aerosol type, as well as about the aerosol optical depth (AOD), at least for low and moderate aerosol loads. An additional sensitivity study with synthetic data has been carried out to quantify the theoretical accuracy and precision of the aerosol properties (AOD, size distribution parameters, etc.) retrieved by GRASP using NSR observations as input. As a result, the theoretical accuracy of AOD is within ±0.02 for AOD values lower than or equal to 0.4, while the theoretical precision goes from 0.01 to 0.05 when AOD at 467?nm varies from 0.1 to 0.5. NSR measurements recorded at Valladolid (Spain) with an all-sky camera for more than 2 years have been inverted with GRASP. The retrieved aerosol properties are compared with independent values provided by co-located AERONET (AErosol RObotic NETwork) measurements. AODs from both data sets correlate with determination coefficient (r2) values of about 0.87. Finally, the novel multi-pixel approach of GRASP is applied to daily camera radiances together by constraining the temporal variation in certain aerosol properties. This temporal linkage (multi-pixel approach) provides promising results, reducing the highly temporal variation in some aerosol properties retrieved with the standard (one by one or single-pixel) approach. This work implies an advance in the use of all-sky cameras for the retrieval of aerosol properties.