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@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 = {calibration transfer, Langley ratio method, photometer calibration},

pubstate = {published},

tppubtype = {article}

}

@article{atmos15060635,

title = {The Recovery and Re-Calibration of a 13-Month Aerosol Extinction Profiles Dataset from Searchlight Observations from New Mexico, after the 1963 Agung Eruption},

author = {J.C. Antuña-Marrero and G.W. Mann and J. Barnes and A. Calle and S.S. Dhomse and V.E. Cachorro and T. Deshler and Z. Li and N. Sharma and L. Elterman},

url = {https://www.mdpi.com/2073-4433/15/6/635},

doi = {10.3390/atmos15060635},

issn = {2073-4433},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

journal = {Atmosphere},

volume = {15},

number = {6},

abstract = {The recovery and re-calibration of a dataset of vertical aerosol extinction profiles of the 1963/64 stratospheric aerosol layer measured by a searchlight at 32°N in New Mexico, US, is reported. The recovered dataset consists of 105 aerosol extinction profiles at 550 nm that cover the period from December 1963 to December 1964. It is a unique record of the portion of the aerosol cloud from the March 1963 Agung volcanic eruption that was transported into the Northern Hemisphere subtropics. The data-recovery methodology involved re-digitizing the 105 original aerosol extinction profiles from individual Figures within a research report, followed by the re-calibration. It involves inverting the original equation used to compute the aerosol extinction profile to retrieve the corresponding normalized detector response profile. The re-calibration of the original aerosol extinction profiles used Rayleigh extinction profiles calculated from local soundings. Rayleigh and aerosol slant transmission corrections are applied using the MODTRAN code in transmission mode. Also, a best-estimate aerosol phase function was calculated from observations and applied to the entire column. The tropospheric aerosol phase function from an AERONET station in the vicinity of the searchlight location was applied between 2.76 to 11.7 km. The stratospheric phase function, applied for a 12.2 to 35.2 km altitude range, is calculated from particle-size distributions measured by a high-altitude aircraft in the vicinity of the searchlight in early 1964. The original error estimate was updated considering unaccounted errors. Both the re-calibrated aerosol extinction profiles and the re-calibrated stratospheric aerosol optical depth magnitudes showed higher magnitudes than the original aerosol extinction profiles and the original stratospheric aerosol optical depth, respectively. However, the magnitudes of the re-calibrated variables show a reasonable agreement with other contemporary observations. The re-calibrated stratospheric aerosol optical depth demonstrated its consistency with the tropics-to-pole decreasing trend, associated with the major volcanic eruption stratospheric aerosol pattern when compared to the time-coincident stratospheric aerosol optical depth lidar observations at Lexington at 42° N.},

keywords = {LIDAR, searchlight, stratospheric aerosol, tropospheric aerosol},

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 = {ESA, LIME, lunar irradiance, moon, radiometry},

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 = {aerosol inversion, AOD, GRASP, zenith sky radiance},

pubstate = {published},

tppubtype = {article}

}

@article{Añel2023,

title = {Documenting the Impacts of Climate Change on the Middle and Upper Atmosphere and Atmospheric Drag of Space Objects},

author = {Añel, J. A. and I. Cnossen and J. C. Antuña-Marrero and G. Beig and M. K. Brown and E. Doornbos and R. García and L. Gray and D. R. Marsh and S. Osprey and M. G. Mlynczak and S. M. Mutschler and P. Pišoft and V. Sofieva and P. Šácha and L. de la Torre and S.R. Zhang},

url = {https://www.sparc-climate.org/wp-content/uploads/sites/5/2023/08/SPARCnewsletter61Jul23.pdf},

issn = {1245-4680},

year  = {2023},

date = {2023-07-01},

journal = {SPARC Newsletter},

number = {61},

pages = {22},

keywords = {GHG},

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 = {ceilometer, GRASP algorithm, LIDAR, Satellite remote sensing, Sulphur dioxide, sun-photometer, Volcanic sulphates},

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 = {atmospheric aerosols, cloud cover, dimming/brightening, early instrumental data, surface solar radiation},

pubstate = {published},

tppubtype = {article}

}

@article{Barja2023,

title = {Surface shortwave cloud radiative effect of cumulus and stratocumulus-cumulus cloud types in the Caribbean area (Camagüey Cuba, 2010-2016)},

author = {Barja, B. and Rosas, J. and Cachorro, V. E. and Toledano, C. and Antuña-Marrero, J. C. and Estevan, R. and de Frutos, A.},

editor = {Atmósfera},

doi = {10.20937/ATM.52858},

year  = {2023},

date = {2023-01-01},

journal = {36},

volume = {(1)},

pages = {41–56},

abstract = {The effects of cumulus (Cu) clouds and the combination of stratocumulus-cumulus (Sc-Cu) clouds on solar radiation at the Earth’s surface were evaluated at Camagüey, Cuba, during a 6-yr period (from June 2010 to May 2016). Two methods to calculate the cloud radiative effect (CRE) were employed. The first method (CREm) uses solar irradiances in cloudy conditions from actinometric observations, where cloud information was also reported by visual observation. In the second method (CRE0) surface solar irradiances were estimated for both cloudy and clear sky conditions using a 1-D radiative transfer model, and cloud optical depth (COD) retrieved from an AERONET sun-photometer as the main input. A temporal correspondence criterion between COD retrievals and actinometric observations was performed in order to classify the COD of each cloud type. After the application of this criterion, the COD belonging to the optically thin clouds was removed. Finally, 255 and 732 COD observations for Cu and Sc-Cu, respectively, were found. Results show a statistically significant difference at the 95% confidence level between CRE calculated for Sc-Cu and Cu, using both methods. Mean values of CREm and CRE0 for Cu (Sc-Cu) were ?442 (?390) and ?460 (?417) Wm–2, respectively. CRE0 shows a linear relation with ln(COD), with stronger correlation at a lower solar zenith angle. The shortwave cloud effect efficiency (CEE) for the two cloud types sharply decreases with the increase of the COD value up to 20. For larger COD, the CEE is less sensitive to the increase of COD.},

keywords = {cloud effect efficiency (CEE), cloud effects on solar radiation (CRE) at surface, cloud optical depth (COD), cumulus and stratocumulus},

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 = {aerosol radiative properties, ceilometer, GAME, GRASP, Longwave radiative effect, Sun-sky photometer},

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 = {aerosol climatology, aerosol optical depth, Angstrom Exponent, caelis, lunar photometry},

pubstate = {published},

tppubtype = {article}

}

@article{García2022b,

title = {Spectral Aerosol Radiative Forcing and Efficiency of the La Palma Volcanic Plume over the Izaña Observatory},

author = {R.D. García and O.E. García and E. Cuevas-Agulló and A. Barreto and V.E. Cachorro and C. Marrero and F. Almansa and R. Ramos and M. Pó},

url = {https://www.mdpi.com/2072-4292/15/1/173},

doi = {10.3390/rs15010173},

issn = {2072-4292},

year  = {2022},

date = {2022-12-28},

urldate = {2023-01-01},

journal = {Remote Sensing},

volume = {15(1)},

number = {17},

abstract = {On 19 September 2021, a volcanic eruption began on the island of La Palma (Canary Islands, Spain). The eruption has allowed the assessment of an unprecedented multidisciplinary study on the effects of the volcanic plume. This work presents the estimation of the spectral direct radiative forcing (ΔF) and efficiency (ΔFEff) from solar radiation measurements at the Izaña Observatory (IZO) located on the island of Tenerife (∼140 km from the volcano). During the eruption, the IZO was affected by different types of aerosols: volcanic, Saharan mineral dust, and a mixture of volcanic and dust aerosols. Three case studies were identified using ground-based (lidar) data, satellite-based (Sentinel-5P Tropospheric Monitoring Instrument, TROPOMI) data, reanalysis data (Modern-Era Retrospective Analysis for Research and Applications, version 2, MERRA-2), and backward trajectories (Flexible Trajectories, FLEXTRA), and subsequently characterised in terms of optical and micro-physical properties using ground-based sun-photometry measurements. Despite the ΔF of the volcanic aerosols being greater than that of the dust events (associated with the larger aerosol load present), the ΔFEff was found to be lower. The spectral ΔFEff values at 440 nm ranged between −1.9 and −2.6 Wm−2nm−1AOD−1 for the mineral dust and mixed volcanic and dust particles, and between −1.6 and −3.3 Wm−2nm−1AOD−1 for the volcanic aerosols, considering solar zenith angles between 30∘ and 70∘, respectively.},

keywords = {Aerosol Properties, aerosol radiative properties},

pubstate = {published},

tppubtype = {article}

}

@article{CAPPELLETTI2022119373,

title = {Vertical profiles of black carbon and nanoparticles pollutants measured by a tethered balloon in Longyearbyen (Svalbard islands)},

author = {D. Cappelletti and C. Petroselli and D. Mateos and M. Herreras and L. Ferrero and N. Losi and A. Gregori and C. Frangipani and G. La Porta and M. Lonardi and D. G. Chernov and A. Dekhtyareva},

url = {https://www.sciencedirect.com/science/article/pii/S1352231022004381},

doi = {https://doi.org/10.1016/j.atmosenv.2022.119373},

issn = {1352-2310},

year  = {2022},

date = {2022-09-09},

urldate = {2022-01-01},

journal = {Atmospheric Environment},

volume = {290},

pages = {119373},

abstract = {Airborne meteorological and aerosol measurements have been performed in Longyearbyen (Svalbard islands) in the summer of 2018, coupling an instrumental aerosol payload with a meteorological radiosonde deployed on a tethered balloon. More than 70 vertical profiles of aerosol and meteorological properties have been recorded up to a maximum altitude of 1.2 km. As a main result, the present work provides a homogeneous gridded dataset of vertical profiles of equivalent black carbon (eBC) and nanoparticles (NP) concentrations and associated meteorological data (temperature, T, relative humidity, RH, pressure, P) to be employed for future modelling studies of Arctic pollution. Mean values (±SD) of eBC and NP below 500 m were 110 ± 10 ng m?3 and 1400 ± 400 particles cm?3, respectively. Mean values above 500 m were 150 ± 30 ng m?3 and 1000 ± 350 particles cm?3, respectively. Group medians of maximum eBC and NP concentrations in vertical profiles with temperature inversions were significantly higher than for those without inversion. The dataset has been complemented by continuous ground measurements of eBC with an average value of 208 ± 130 ng m?3 (median value 110 ± 70 ng m?3) for the entire campaign; the ground-based background (absence of local emission) eBC value was below 100 ng m?3 while maximum values were in the 1000–2000 ng m?3 range. Median eBC concentration measured at ground for 2 h before the tethered balloon launch was higher when temperature inversion was observed. The ground-based measurements, coupled with aerosol optical depth measurements, allowed for a preliminary discussion of two case studies related to high pollutants concentration events.},

keywords = {Aerosol vertical profiles, Arctic pollution, Black carbon, Nanoparticles},

pubstate = {published},

tppubtype = {article}

}

@article{Vaquero-Martínez2022,

title = {Comparison of CIMEL sun-photometer and ground-based GNSS integrated water vapor over south-western European sites},

author = {Javier Vaquero-Martínez and André F. Bagorrilha and Manuel Antón and Juan C. Antuña-Marrero and Victoria E. Cachorro},

url = {https://www.sciencedirect.com/science/article/pii/S0169809522002034},

doi = {https://doi.org/10.1016/j.atmosres.2022.106217},

issn = {0169-8095},

year  = {2022},

date = {2022-09-01},

urldate = {2022-01-01},

journal = {Atmospheric Research},

volume = {275},

pages = {106217},

abstract = {This work analyzes the integrated water vapor (IWV) measured at six Aerosol Robotic Network (AERONET) stations with nearby global navigation satellite system (GNSS) in the Iberian Peninsula for the period 2007–2018. It is shown that both instruments have a high correlation (R2 > 0.91), with small mbe below 1.5 mm and standard deviation (SD) below 2 mm. However, some dependences have been observed when MBE and SD are represented in bins of three variables: IWV, solar zenith angle (SZA), and aerosol optical depth (AOD). The greater or lesser amount of water vapor in the atmosphere seemed to be the more influential variable, increasing dry bias and SD with increasing IWV. Moreover, high SZA values were related to SD increases. A clear seasonal cycle for Cimel–GNSS differences was observed which was mainly related to IWV seasonal cycle. Additionally, AOD did not show a remarkable influence on Cimel–GNSS differences. Finally, the monthly differences are also analyzed with metadata information about Cimel device ID numbers, showing that, for long-term studies, this information can be very valuable.},

keywords = {Comparison, GNSS, Sun photometer, sun-photometer, Water vapor},

pubstate = {published},

tppubtype = {article}

}

@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}

}

@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 = {all-sky camera, clouds, image analylis, polynomials, stars},

pubstate = {published},

tppubtype = {article}

}

@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 = {model, Radiative transfer, Solar radiation},

pubstate = {published},

tppubtype = {article}

}

@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 = {AERONET, Arctic, Integrated water vapor, radiosonde, Sun photometer},

pubstate = {published},

tppubtype = {article}

}

@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 = {aerosol, all-sky camera, GRASP, retrieval},

pubstate = {published},

tppubtype = {article}

}

@article{ClimatologyofaerosolsovertheCaribbeanislandsaerosoltypessynopticpatternsandtransport,

title = {Climatology of aerosols over the Caribbean islands: aerosol types, synoptic patterns and transport},

author = {Albeht Rodríguez-Vega and Juan Carlos Antuña-Marrero and David Barriopedro and Ricardo García-Herrera and Victoria E. Cachorro Revilla and Ángel Frutos Baraja and Juan Carlos Antuña-Sánchez},

url = {https://journals.ametsoc.org/view/journals/apme/aop/JAMC-D-21-0015.1/JAMC-D-21-0015.1.xml},

doi = {10.1175/JAMC-D-21-0015.1},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Journal of Applied Meteorology and Climatology},

publisher = {American Meteorological Society},

address = {Boston MA, USA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}