Dr. Roberto Román

@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{Graßl2024,

title = {From Polar Day to Polar Night: A Comprehensive Sun and Star Photometer Study of Trends in Arctic Aerosol Properties in Ny-Ålesund, Svalbard},

author = {Sandra Graßl and Christoph Ritter and Jonas Wilsch and Richard Herrmann and Lionel Doppler and Roberto Román},

url = {https://www.mdpi.com/2072-4292/16/19/3725},

doi = {10.3390/rs16193725},

issn = {2072-4292},

year  = {2024},

date = {2024-07-22},

urldate = {2024-01-01},

journal = {Remote Sensing},

volume = {16},

number = {19},

abstract = {The climate impact of Arctic aerosols, like the Arctic Haze, and their origin are not fully understood. Therefore, long-term aerosol observations in the Arctic are performed. In this study, we present a homogenised data set from a sun and star photometer operated in the European Arctic, in Ny-Ålesund, Svalbard, of the 20 years from 2004–2023. Due to polar day and polar night, it is crucial to use observations of both instruments. Their data is evaluated in the same way and follows the cloud-screening procedure of AERONET. Additionally, an improved method for the calibration of the star photometer is presented. We found out, that autumn and winter are generally more polluted and have larger particles than summer. While the monthly median Aerosol Optical Depth (AOD) decreases in spring, the AOD increases significantly in autumn. A clear signal of large particles during the Arctic Haze can not be distinguished from large aerosols in winter. With autocorrelation analysis, we found that AOD events usually occur with a duration of several hours. We also compared AOD events with large-scale processes, like large-scale oscillation patterns, sea ice, weather conditions, or wildfires in the Northern Hemisphere but did not find one single cause that clearly determines the Arctic AOD. Therefore the observed optical depth is a superposition of different aerosol sources.},

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{Salgueiro2023,

title = {Characterization of Tajogaite volcanic plumes detected over the Iberian Peninsula from a set of satellite and ground-based remote sensing instrumentation},

author = {V. Salgueiro and J. L. Guerrero-Rascado and M. J. Costa and R. Román and A. Cazorla and A. Serrano and F. Molero and M. Sicard and C. Córdoba-Jabonero and D. Bortoli and A. Comerón and F. T. Couto and M. Á. López-Cayuela and D. Pérez-Ramírez and M. Potes and J. A. Muñiz-Rosado and M. A. Obregón and R. Barragán and D. C. F. S. Oliveira and J. Abril-Gago and R. González and C. Gíl-Díaz and I. Foyo-Moreno and C. Muñoz-Porcar and M. J. Granados-Muñoz and A. Rodríguez-Gómez and M. Herreras-Giralda and J. A. Bravo-Aranda and C. V. Carvajal-Pérez and A. Barreto and L. Alados-Arboledas},

url = {https://www.sciencedirect.com/science/article/pii/S0034425723002353},

doi = {https://doi.org/10.1016/j.rse.2023.113684},

issn = {0034-4257},

year  = {2023},

date = {2023-06-13},

urldate = {2023-01-01},

journal = {Remote Sensing of Environment},

volume = {295},

pages = {113684},

abstract = {Three volcanic plumes were detected during the Tajogaite volcano eruptive activity (Canary Islands, Spain, September–December 2021) over the Iberian Peninsula. The spatiotemporal evolution of these events is characterised by combining passive satellite remote sensing and ground-based lidar and sun-photometer systems. The inversion algorithm GRASP is used with a suite of ground-based remote sensing instruments such as lidar/ceilometer and sun-photometer from eight sites at different locations throughout the Iberian Peninsula. Satellite observations showed that the volcanic ash plumes remained nearby the Canary Islands covering a mean area of 120 ± 202 km2 during the whole period of eruptive activity and that sulphur dioxide plumes reached the Iberian Peninsula. Remote sensing observations showed that the three events were mainly composed of sulphates, which were transported from the volcano into the free troposphere. The high backscatter-related Ångström exponents for wavelengths 532–1064 nm (1.17 ± 0.20 to 1.40 ± 0.24) and low particle depolarization ratios (0.08 ± 0.02 to 0.09 ± 0.02), measured by the multi-wavelength Raman lidar, hinted at the presence of spherical small particles. The layer aerosol optical depth at 532 nm (AODL532) obtained from lidar measurements contributed between 49% and 82% to the AERONET total column AOD at 532 nm in event II (11–13 October). According to the GRASP retrievals, the layer aerosol optical depth at 440 nm (AODL440) was higher in all sites during event II with values between 0.097 (Badajoz) and 0.233 (Guadiana-UGR) and lower in event III (19–21 October) varying between 0.003 (Granada) and 0.026 (Évora). Compared with the GRASP retrievals of total column AOD at 440 nm, the AODL440 had contributions between 21% and 52% during event II. In the event I (25–28 September), the mean volume concentrations (VC) varied between 5 ± 4 ?m3cm?3 (El-Arenosillo/Huelva) and 17 ± 10 ?m3cm?3 (Guadiana-UGR), while in event II this variation was from 11 ± 7 ?m3cm?3 (Badajoz) to 27 ± 10 ?m3cm?3 (Guadiana-UGR). Due to the impact of volcanic events on atmospheric and economic fields, such as radiative forcing and airspace security, a proper characterization is required. This work undertakes it using advanced instrumentation and methods.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Montero-Martín2023,

title = {Reconstruction of daily global solar radiation under all-sky and cloud-free conditions in Badajoz (Spain) since 1929},

author = {Javier Montero-Martín and Manuel Antón and José Manuel Vaquero and Roberto Román and Javier Vaquero-Martinez and Alejandro J. P. Aparicio and Arturo Sanchez-Lorenzo},

url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.8042},

doi = {https://doi.org/10.1002/joc.8042},

year  = {2023},

date = {2023-02-16},

journal = {International Journal of Climatology},

volume = {n/a},

number = {n/a},

abstract = {Abstract This work analyses the long-term temporal variability of the annual and seasonal series of reconstructed global solar radiation for both all-sky and cloud-free conditions in Badajoz (Spain) over the 1929–2015 period. Specifically, daily values of global horizontal irradiation (GHI) for all-sky cases are derived from a semiempirical method based on the relationship between the cloud modification factor and sunshine duration records. Additionally, cloud-free situations are selected using cloud cover (CC) information recorded by surface observations. Regarding GHI linear trends for all-sky conditions, three periods are clearly identified: during the 1929–1950 period, there is a positive and statistically significant trend of +4.18?W·m?2·decade?1. It is followed by a significant dimming with a trend of ?3.72?W·m?2·decade?1 between 1951 and 1984. GHI levels increase again from 1985 to 2015 with a statistically significant trend of +2.04?W·m?2·decade?1. The seasonal trends are found to be statistically significant only in summer for all the three subperiods. With the goal to find out the possible causes of the reconstructed GHI trends, the temporal variability of the CC was also analysed. It was observed that CC has a statistically significant negative trend between 1985 and 2015 which may partially explain the GHI increase shown for this period. In contrast, not statistically significant trends were found in the annual and seasonal CC series before 1985. The long-term evolution of the GHI under cloud-free conditions exhibits the same pattern as all-sky conditions: an increase during 1929–1950, followed by a decrease in 1951–1984 and then a new increase from 1985 to 2015. Therefore, the positive (negative) linear trends in GHI reported in this study could be partially related to a decrease (increase) in the aerosol load during the analysed three subperiods.},

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.},

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tppubtype = {article}

}