Dr. Ramiro González

@article{Antuña-Marrero2025b,

title = {Comparing Integrated Water Vapor Sun Photometer Observations Over the Arctic With ERA5 and MERRA-2 Reanalyses},

author = {J. C. Antuña-Marrero and R. Román and V. E. Cachorro and D. Mateos and C. Toledano and A. Calle and J. C. Antuña-Sánchez and R. Gonzalez and M. Antón and J. Vaquero-Martínez and Á.  M. Frutos Baraja},

url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2024JD041120},

doi = {https://doi.org/10.1029/2024JD041120},

year  = {2025},

date = {2025-03-17},

urldate = {2025-01-01},

journal = {Journal of Geophysical Research: Atmospheres},

volume = {130},

number = {6},

pages = {e2024JD041120},

abstract = {Abstract Atmospheric water vapor, a greenhouse gas, is increasing in the Arctic. It is a scientific challenge to understand the causes for this increase and determine adaptation and mitigation actions to confront its climatic effects. During the last decades, spatial and temporal coverage of water vapor satellite observations increased notably, and reanalysis water vapor estimates have steadily improved. However, the scarce spatial and temporal coverage in the Arctic of integrated water vapor (IWV) surface-based observations limits the representativeness of satellite observations and reanalysis estimate validations. Recently, we validated sun photometer IWV (IWVsp) observations with IWV from radiosondes in the Arctic. Here, we compare the hourly means of IWVsp from 13 Arctic AERONET stations and the IWV from ERA-5 and MERRA-2 reanalyses. The comparison is conducted at hourly timescale for individual stations for two Arctic regions and for the whole Arctic. The comparison showed a moist bias of IWV from reanalyses with respect to IWVsp. The individual station wise pattern shows slightly better accuracy and precision for ERA5 than for MERRA-2 also evident at the selected subregional scale. The differences of IWV from ERA5 and MERRA-2 and IWVsp show no dependence on IWVsp nor the solar zenith angle. This study corroborates that IWVsp may be used for validations of satellite IWV observations and IWV reanalyses products.},

note = {e2024JD041120 2024JD041120},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Antuña-Marrero2025,

title = {A Long and Fruitful Cooperation in Atmospheric Aerosol Research between Cuba and Spain},

author = {Juan Carlos Antuña-Marrero and Ángel Frutos and Rene Estevan and Victoria Cachorro and Boris Barja and Sandra Mogo and Albeht Rodríguez-Vega and Carlos Toledano and Frank García and David Mateos and Juan Carlos Antuña-Sánchez and Ramiro González and Jorge Rosas and Roberto Román and Luis Enrique Ramos-Guadalupe and Abel Calle and Iralmy Y. Platero and Carlos Hernández and Nelson Díaz and Joel Díaz},

url = {https://journals.ametsoc.org/view/journals/bams/106/2/BAMS-D-23-0138.1.xml},

doi = {10.1175/BAMS-D-23-0138.1},

year  = {2025},

date = {2025-02-21},

urldate = {2025-01-01},

journal = {Bulletin of the American Meteorological Society},

volume = {106},

number = {2},

pages = {E364 - E377},

publisher = {American Meteorological Society},

address = {Boston MA, USA},

abstract = {Cuban and Spanish scientists have been studying the properties of atmospheric aerosols in Camagüey, Cuba, for more than 15?years, achieving notable scientific results at the local, regional, and global levels. Using instruments and expertise supplied by Spain, Cuban scientists have characterized local aerosol optical and microphysical properties and their chemical composition and optical absorbing properties. Aerosol optical depth (AOD) and Ångström exponent observations were used to validate MODIS satellite observations and broadband AOD from local pyrheliometers. Sun photometer cloud optical depth allowed us to characterize local cloudiness and its radiative forcing. Scientific work included climatologies of the solar radiation for the last four decades at Camagüey and of aerosols in the Caribbean basin in the last two decades. Another result was designing, building, and processing of a low-cost all-sky camera. Besides scientific results, the cooperation allowed the Cuban sun photometer observations to contribute to the Red Ibérica de Medida Fotométrica de Aerosoles and AERONET. A workshop celebrating 10?years of cooperation was held at Camagüey in 2016. The workshop participants evaluated the progress, difficulties, and challenges and inaugurated a Spanish angular calibration bench for solar radiation sensors at Camagüey. The workshop also included the first visit of a NASA scientist to Cuba, the only one visit. Cuban scientists became members of the International Science Team of the NASA Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite mission, just launched, participating in its prelaunch activities. Considering the joint capabilities we developed, Cuban–Spanish contribution is expected for the TEMPO postlaunch validation campaign.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Herrero-Anta2025,

title = {Impact of cloud presence on sky radiances and the retrieval of aerosol properties},

author = {Sara Herrero-Anta and Roberto Román and Daniel González-Fernández and Claudia Emde and David Mateos and Celia Herrero Barrio and Ramiro González and Oleg Dubovik and Carlos Toledano and Abel Calle and Victoria E. Cachorro and Bernhard Mayer and Ángel M. de Frutos},

url = {https://www.sciencedirect.com/science/article/pii/S0169809525000304},

doi = {https://doi.org/10.1016/j.atmosres.2025.107938},

issn = {0169-8095},

year  = {2025},

date = {2025-01-18},

urldate = {2025-01-01},

journal = {Atmospheric Research},

volume = {317},

pages = {107938},

abstract = {This paper explores the influence of the presence of clouds on sky radiances. It also analyses their impact on the retrieval of aerosol properties when using an inversion algorithm whose radiative transfer model (RTM) is designed for cloud-free atmospheres. For that, synthetic observations are simulated for 9 partially cloudy skies and for their equivalent cloud-free skies, considering 16 different aerosol scenarios. A parameter named cloud enhancement factor (CEF) has been used to determine the modifications induced in the sky radiances by each partially cloudy scenario with respect to the cloud-free sky. This parameter indicates that the sky radiances remaining after applying a cloud-screening are affected by the presence of clouds. In general, they show enhancements between 0 and 20 % with respect to the cloud-free radiances, depending on the cloudy conditions and the scattering angle. The synthetic observations used as input for the retrieval of aerosol properties are the ones required by the inversion strategy used, GRASPpac: the aerosol optical depth (AOD) and sky radiances at 4 different wavelengths together with the ceilometer range corrected signal (RCS). In partially cloudy scenarios with low CEFs, the aerosol properties do not present significant changes with respect to the cloud-free conditions. However, for partially cloudy scenarios with higher CEFs, a clear differentiation between the aerosol optical properties retrieved with and without clouds is observed. In these scenarios, the precision of the retrieval is similar for both conditions, but the accuracy is lower for the cloudy conditions. In particular, under partially cloudy conditions, it is observed an overestimation of the real refractive index (RRI) and the single scattering albedo (SSA) between 0.05 and 0.06 and between 0.03 and 0.06 respectively, and an underestimation of the asymmetry factor (g) and the imaginary refractive index (IRI) of about ?0.02 and ? 0.005, respectively. These values slightly vary with the aerosol load and wavelength for the RRI and SSA. The effects on the size distribution parameters are very small, concluding that the impact of clouds is noticeable in the optical properties but not so much in the microphysical part.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ALongandFruitfulCooperationinAtmosphericAerosolResearchbetweenCubaandSpain,

title = {A Long and Fruitful Cooperation in Atmospheric Aerosol Research between Cuba and Spain},

author = {Juan Carlos Antuña-Marrero and Ángel Frutos and Rene Estevan and Victoria Cachorro and Boris Barja and Sandra Mogo and Albeht Rodríguez-Vega and Carlos Toledano and Frank García and David Mateos and Juan Carlos Antuña-Sánchez and Ramiro González and Jorge Rosas and Roberto Román and Luis Enrique Ramos-Guadalupe and Abel Calle and Iralmy Y. Platero and Carlos Hernández and Nelson Díaz and Joel Díaz},

url = {https://journals.ametsoc.org/view/journals/bams/106/2/BAMS-D-23-0138.1.xml},

doi = {10.1175/BAMS-D-23-0138.1},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

journal = {Bulletin of the American Meteorological Society},

volume = {106},

number = {2},

pages = {E364 - E377},

publisher = {American Meteorological Society},

address = {Boston MA, USA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1029/2024JD041120,

title = {Comparing Integrated Water Vapor Sun Photometer Observations Over the Arctic With ERA5 and MERRA-2 Reanalyses},

author = {J. C. Antuña-Marrero and R. Román and V. E. Cachorro and D. Mateos and C. Toledano and A. Calle and J. C. Antuña-Sánchez and R. Gonzalez and M. Antón and J. Vaquero-Martínez and Á.  M. Frutos Baraja},

url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2024JD041120},

doi = {https://doi.org/10.1029/2024JD041120},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

journal = {Journal of Geophysical Research: Atmospheres},

volume = {130},

number = {6},

pages = {e2024JD041120},

abstract = {Abstract Atmospheric water vapor, a greenhouse gas, is increasing in the Arctic. It is a scientific challenge to understand the causes for this increase and determine adaptation and mitigation actions to confront its climatic effects. During the last decades, spatial and temporal coverage of water vapor satellite observations increased notably, and reanalysis water vapor estimates have steadily improved. However, the scarce spatial and temporal coverage in the Arctic of integrated water vapor (IWV) surface-based observations limits the representativeness of satellite observations and reanalysis estimate validations. Recently, we validated sun photometer IWV (IWVsp) observations with IWV from radiosondes in the Arctic. Here, we compare the hourly means of IWVsp from 13 Arctic AERONET stations and the IWV from ERA-5 and MERRA-2 reanalyses. The comparison is conducted at hourly timescale for individual stations for two Arctic regions and for the whole Arctic. The comparison showed a moist bias of IWV from reanalyses with respect to IWVsp. The individual station wise pattern shows slightly better accuracy and precision for ERA5 than for MERRA-2 also evident at the selected subregional scale. The differences of IWV from ERA5 and MERRA-2 and IWVsp show no dependence on IWVsp nor the solar zenith angle. This study corroborates that IWVsp may be used for validations of satellite IWV observations and IWV reanalyses products.},

note = {e2024JD041120 2024JD041120},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{delBarrio2024h,

title = {CAECENET: An automatic system processing photometer and ceilometer data from different networks to provide columnar and vertically-resolved aerosol properties},

author = {Celia Herrero del Barrio and Roberto Román and Ramiro González and Alberto Cazorla and Marcos Herreras-Giralda and Juan Carlos Antuña-Sánchez and Francisco Molero and Francisco Navas-Guzmán and Antonio Serrano and María Ángeles Obregón and Yolanda Sola and Marco Pandolfi and Sara Herrero-Anta and Daniel González-Fernández and Jorge Muñiz-Rosado and David Mateos and Abel Calle and Carlos Toledano and Victoria E. Cachorro and Ángel M. de Frutos},

doi = {10.1371/journal.pone.0311990},

year  = {2024},

date = {2024-12-27},

urldate = {2024-12-27},

journal = {PloS one},

volume = {19},

number = {12},

pages = {e0311990},

publisher = {Public Library of Science San Francisco, CA USA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{rs16203821,

title = {Retrieval of Solar Shortwave Irradiance from All-Sky Camera Images},

author = {Daniel González-Fernández and Roberto Román and David Mateos and Celia Herrero del Barrio and Victoria E. Cachorro and Gustavo Copes and Ricardo Sánchez and Rosa Delia García and Lionel Doppler and Sara Herrero-Anta and Juan Carlos Antuña-Sánchez and África Barreto and Ramiro González and Javier Gatón and Abel Calle and Carlos Toledano and Ángel Frutos},

url = {https://www.mdpi.com/2072-4292/16/20/3821},

doi = {10.3390/rs16203821},

issn = {2072-4292},

year  = {2024},

date = {2024-10-14},

urldate = {2024-01-01},

journal = {Remote Sensing},

volume = {16},

number = {20},

abstract = {The present work proposes a new model based on a convolutional neural network (CNN) to retrieve solar shortwave (SW) irradiance via the estimation of the cloud modification factor (CMF) from daytime sky images captured by all-sky cameras; this model is named CNN-CMF. To this end, a total of 237,669 sky images paired with SW irradiance measurements obtained by using pyranometers were selected at the following three sites: Valladolid and Izaña, Spain, and Lindenberg, Germany. This dataset was randomly split into training and testing sets, with the latter excluded from the training model in order to validate it using the same locations. Subsequently, the test dataset was compared with the corresponding SW irradiance measurements obtained by the pyranometers in scatter density plots. The linear fit shows a high determination coefficient (R2) of 0.99. Statistical analyses based on the mean bias error (MBE) values and the standard deviation (SD) of the SW irradiance differences yield results close to ?2% and 9%, respectively. The MBE indicates a slight underestimation of the CNN-CMF model compared to the measurement values. After its validation, model performance was evaluated at the Antarctic station of Marambio (Argentina), a location not used in the training process. A similar comparison between the model-predicted SW irradiance and pyranometer measurements yielded R2=0.95, with an MBE of around 2% and an SD of approximately 26%. Although the precision provided by the SD at the Marambio station is lower, the MBE shows that the model’s accuracy is similar to previous results but with a slight overestimation of the SW irradiance. Finally, the determination coefficient improved to 0.99, and the MBE and SD are about 3% and 11%, respectively, when the CNN-CMF model is used to estimate daily SW irradiation values.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gonzalez2024CCNeural,

title = {A neural network to retrieve cloud cover from all-sky cameras: A case of study over Antarctica},

author = {Daniel González-Fernández and Roberto Román and Juan Carlos Antuña-Sánchez and Victoria E. Cachorro and Gustavo Copes and Sara Herrero-Anta and Celia Herrero del Barrio and África Barreto and Ramiro González and Ramón Ramos and Patricia Martín and David Mateos and Carlos Toledano and Abel Calle and Ángel Frutos},

url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.4834},

doi = {https://doi.org/10.1002/qj.4834},

year  = {2024},

date = {2024-08-28},

journal = {Quarterly Journal of the Royal Meteorological Society},

volume = {n/a},

number = {n/a},

abstract = {Abstract We present a new model based on a convolutional neural network (CNN) to predict daytime cloud cover (CC) from sky images captured by all-sky cameras, which is called CNN-CC. A total of 49,016 daytime sky images, recorded at different Spanish locations (Valladolid, La Palma, and Izaña) from two different all-sky camera types, are manually classified into different CC (oktas) values by trained researchers. Subsequently, the images are randomly split into a training set and a test set to validate the model. The CC values predicted by the CNN-CC model are compared with the observations made by trained people on the test set, which serve as reference. The predicted CC values closely match the reference values within ±$$ ± $$1?oktas in 99% of the cloud-free and overcast cases. Moreover, this percentage is above 93% for the rest of partially cloudy cases. The mean bias error (MBE) and standard deviation (SD) of the differences between the predicted and reference CC values are calculated, resulting in MBE=0.007$$ mathrmMBE=0.007 $$?oktas and SD=0.674$$ mathrmSD=0.674 $$?oktas. The MBE and SD are also represented for different intervals of measured aerosol optical depth and Ångström exponent values, revealing that the performance of the CNN-CC model does not depend on aerosol load or size. Once the model is validated, the CC obtained from a set of images captured every 5?min, from January 2018 to March 2022, at the Antarctic station of Marambio (Argentina) is compared against direct field observations of CC (not from images) taken at this location, which is not used in the training process. As a result, the model slightly underestimates the observations with an MBE of ?$$ - $$0.3?oktas. The retrieved data are analyzed in detail. The monthly and annual CC values are calculated. Overcast conditions are the most frequent, accounting for 46.5% of all observations throughout the year, rising to 64.5% in January. The annual mean CC value at this location is 5.5?oktas, with a standard deviation of approximately 3.1?oktas. A similar analysis is conducted, separating data by hours, but no significant diurnal cycles are observed except for some isolated months.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Almansa2024b,

title = {The Langley ratio method, a new approach for transferring photometer calibration from direct sun measurements},

author = {A. F. Almansa and Á. Barreto and N. Kouremeti and R. González and A. Masoom and C. Toledano and J. Gröbner and R. D. García and Y. González and S. Kazadzis and S. Victori and Ó. Álvarez and F. Maupin and V. Carreño and V. E. Cachorro and E. Cuevas},

url = {https://amt.copernicus.org/articles/17/659/2024/},

doi = {10.5194/amt-17-659-2024},

year  = {2024},

date = {2024-01-26},

urldate = {2024-01-01},

journal = {Atmospheric Measurement Techniques},

volume = {17},

number = {2},

pages = {659–675},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Toledano2024,

title = {LIME: Lunar Irradiance Model of ESA, a new tool for absolute radiometric calibration using the Moon},

author = {C. Toledano and S. Taylor and Á. Barreto and S. Adriaensen and A. Berjón and A. Bialek and R. González and E. Woolliams and M. Bouvet},

url = {https://acp.copernicus.org/articles/24/3649/2024/},

doi = {10.5194/acp-24-3649-2024},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

journal = {Atmospheric Chemistry and Physics},

volume = {24},

number = {6},

pages = {3649–3671},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Herrero-Anta2023,

title = {Retrieval of aerosol properties from zenith sky radiance measurements},

author = {Sara Herrero-Anta and Roberto Román and David Mateos and Ramiro González and Juan Carlos Antuña-Sánchez and Marcos Herreras-Giralda and Antonio Fernando Almansa and Daniel González-Fernández and Celia Herrero del Barrio and Carlos Toledano and Victoria Eugenia Cachorro and Ángel Máximo de Frutos},

url = {https://amt.copernicus.org/articles/16/4423/2023/},

doi = {10.5194/amt-16-4423-2023},

year  = {2023},

date = {2023-10-09},

urldate = {2023-10-09},

journal = {Atmospheric Measurement Techniques},

volume = {16},

number = {19},

pages = {4423–4443},

abstract = {This study explores the potential to retrieve aerosol properties with the GRASP algorithm (Generalized Retrieval of Atmosphere and Surface Properties) using as input measurements of zenith sky radiance (ZSR), which are sky radiance values measured in the zenith direction, recorded at four wavelengths by a ZEN-R52 radiometer. To this end, the ZSR measured at 440, 500, 675 and 870?nm by a ZEN-R52 (ZSRZEN), installed in Valladolid (Spain), is employed. This instrument is calibrated by intercomparing the signal of each channel with coincident ZSR values simulated (ZSRSIM) at the same wavelengths with a radiative transfer model (RTM). These simulations are carried out using the GRASP forward module as RTM and the aerosol information from a co-located CE318 photometer belonging to AERONET (AErosol RObotic NETwork) as input. The dark signal and the signal dependence on temperature are characterized and included in the calibration process. The uncertainties for each channel are quantified by an intercomparison with a co-located CE318 photometer, obtaining lower values for shorter wavelengths; they are between 3?% for 440?nm and 21?% for 870?nm. The proposed inversion strategy for the aerosol retrieval using the ZSRZEN measurements as input, i.e. so-called GRASP-ZEN, assumes the aerosol as an external mixture of five pre-calculated aerosol types. A sensitivity analysis is conducted using synthetic ZSRZEN measurements, pointing out that these measurements are sensitive to aerosol load and type. It also assesses that the retrieved aerosol optical depth (AOD) values in general overestimate the reference ones by 0.03, 0.02, 0.02 and 0.01 for 440, 500, 675 and 870?nm, respectively. The calibrated ZSRZEN measurements, recorded during 2.5 years at Valladolid, are inverted by the GRASP-ZEN strategy to retrieve some aerosol properties like AOD. The retrieved AOD shows a high correlation with respect to independent values obtained from a co-located AERONET CE318 photometer, with determination coefficients (r2) of 0.86, 0.85, 0.79 and 0.72 for 440, 500, 675 and 870?nm, respectively, and finding uncertainties between 0.02 and 0.03 with respect to the AERONET values. Finally, the retrieval of other aerosol properties, like aerosol volume concentration for total, fine and coarse modes (VCT, VCF and VCC, respectively), is also explored. The comparison against independent values from AERONET presents r2 values of 0.57, 0.56 and 0.66 and uncertainties of 0.009, 0.016 and 0.02?µm3?µm?2 for VCT, VCF and VCC, respectively},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bazo2023,

title = {Evaluation of the vertically-resolved aerosol radiative effect on shortwave and longwave ranges using sun-sky photometer and ceilometer measurements},

author = {Elena Bazo and María J. Granados-Muñoz and Roberto Román and Juan Antonio Bravo-Aranda and Alberto Cazorla and Antonio Valenzuela and Ramiro González and Francisco José Olmo and Lucas Alados-Arboledas},

url = {https://www.sciencedirect.com/science/article/pii/S0169809522005038},

doi = {https://doi.org/10.1016/j.atmosres.2022.106517},

issn = {0169-8095},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Atmospheric Research},

volume = {282},

pages = {106517},

abstract = {The aerosol radiative effect (ARE) is one of the atmospheric components still affected by large uncertainty. One of the causes is related to the fact that the longwave (LW) component is usually neglected, even though it is necessary for an accurate quantification of the ARE together with the shortwave component (SW). In this study we have developed a methodology based on the GAME (Global Atmospheric Model) radiative transfer model (RTM) that allows to obtain the radiative effect of the atmospheric aerosol for both spectral ranges in an automated way. The microphysical and optical properties necessary to feed the RTM have been obtained through the GRASP (Generalized Retrieval of Aerosol and Surface Properties) algorithm, with the combination of ceilometer and sun-sky photometer data. Data measured in Granada (Spain) during 2017 have been used for the evaluation and implementation of this methodology. According to the results, the ARE in the SW spectral range (ARESW) varies between 0 and ? 50 Wm?2 for most of the data, whereas the ARE in the LW range (ARELW) varies between 0 and 5 Wm?2, at heights near the surface. In general, the obtained results agree with those found in the literature, with negative values in the SW range (cooling effect) and positive values in the LW (heating effect). The seasonal analysis shows that, for both components, the ARE is more important during the spring and summer seasons, when the aerosol load is greater, as expected. The analysis of the aerosol heating rate (AHR) shows positive values in the SW and negative values in the LW range. The majority of the AHRSW data varies between 0 and 1 Kd?1 during the year whereas the AHRLW does it between 0 and ? 0.15 Kd?1. The seasonal analysis of the AHR shows that the greater monthly average values are found during spring, however there is not much variability along the year, with the exception of February, under the effects of an extreme dust intrusion. The mineral dust particles in this event cause an ARESW of ?130 Wm?2 and an ARELW of 23 Wm?2 (ARELW/ARESW = 17%), thus pointing out that the LW component should not be neglected for coarse mode particles. Additionally, it is observed that the vertical distribution of the aerosol layers strongly influences the ARE and the AHR obtained profiles, affecting the way the atmospheric cooling/heating occurs in the vertical coordinate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{rs15225362,

title = {Analysis of Daytime and Night-Time Aerosol Optical Depth from Solar and Lunar Photometry in Valladolid (Spain)},

author = {Celia Herrero del Barrio and David Mateos and Roberto Román and Ramiro González and Sara Herrero-Anta and Daniel González-Fernández and Abel Calle and Carlos Toledano and Victoria Eugenia Cachorro and Ángel Máximo De Frutos Baraja},

url = {https://www.mdpi.com/2072-4292/15/22/5362},

doi = {10.3390/rs15225362},

issn = {2072-4292},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Remote Sensing},

volume = {15},

number = {22},

abstract = {Aerosol optical depth (AOD) at night-time has become a hot topic in recent years due to the development of new instruments recording accurate ground-based lunar irradiance measurements, and the development of calibration methods and extraterrestrial irradiance models adapted to lunar photometry. This study uses all daytime and night-time AOD data available at Valladolid (Spain) from October 2016 to March 2022 in order to analyze its behavior and the added contribution of night data. The annual, monthly and daily AOD evolution is studied comparing daytime and night-time values and checking the correlation between them. For this purpose, the daily averages are computed, showing an annual pattern, with low AOD values throughout the year (mean value of AOD at 440 nm: 0.122), where winter months have the lower and summer the higher values, as observed in previous studies. All these AOD values are modulated by frequent desert dust events over the Iberian Peninsula, with a strong influence on daily and monthly mean values in February and March, where the strongest desert outbreaks occurred. The added new data confirm these results and the good correlation between daytime and night-time data. Also, a complete daily evolution is shown, observing that AOD and Ångström exponent (AE) mean values vary by only ±0.02 in 24 h, with a maximum value at 06:00 UTC and minimum at 18:00 UTC for both parameters.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}