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@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{rs13020169,

title = {Solar Radiation Climatology in Camagüey, Cuba (1981–2016)},

author = {Juan Carlos Antuña-Sánchez and René Estevan and Roberto Román and Juan Carlos Antuña-Marrero and Victoria E Cachorro and Albeth Rodríguez Vega and Ángel M de Frutos},

url = {https://www.mdpi.com/2072-4292/13/2/169},

doi = {10.3390/rs13020169},

issn = {2072-4292},

year  = {2021},

date = {2021-01-01},

journal = {Remote Sensing},

volume = {13},

number = {2},

abstract = {The transition to renewable energies is an unavoidable step to guarantee a peaceful and sustainable future for humankind. Although solar radiation is one of the main sources of renewable energy, there are broad regions of the planet where it has not been characterized appropriately to provide the necessary information for regional and local planning and design of the different solar powered systems. The Caribbean, and Cuba in particular, lacked until very recently at least one long-term series of surface solar radiation measurements. Here we present the first long-term records of solar radiation for this region. Solar radiation measurements manually conducted and recorded on paper were rescued, reprocessed and quality controlled to develop the solar radiation climatology at the Actinometrical Station of Camagüey, in Cuba (21.422°N; 77.850°W; 122 m a.s.l.) for the period 1981-2016. The diurnal cycle based on the average hourly values of the global, direct and diffuse horizontal variables for the entire period have been determined and analyzed showing the dependence on solar zenith angle (SZA) and clouds. The annual cycle of global solar component given by the mean monthly daily values presents two maxima, one in April and another one in July with values of 5.06 and 4.91 kWh m−2, respectively (18.23 and 17.67 MJ m−2 per day for insolation), and the minimum in December (3.15 kWh m−2 or 11.33 MJ m−2). The maxima are governed by the direct solar components and are modulated by cloudiness. Both, diurnal and annual cycles of the diffuse solar component show a smoothed bell shaped behavior. In general solar radiation at this station presents a strong influence of clouds, with little seasonal variation but with higher values during the rainy season. Daily global radiation annual averages showed its maximum value in the year 1983, with 17.45 MJ m−2 explained by very low cloudiness this year, and the minimum value was reported in 2009 with a value of 12.43 MJ m−2 that could not explained by the cloud coverage or the aerosols optical depths registered that year. The effects of the 1982 El Chichón and 1991 Mount Pinatubo volcanic eruptions on the solar radiation variables at Camagüey are also shown and discussed. The results achieved in this study shown the characteristics of solar radiation in this area and their potential for solar power applications.},

keywords = {climatology, cloud cover, cuba, diffuse, direct radiation, insolation, Solar radiation},

pubstate = {published},

tppubtype = {article}

}

@article{García-Cabrera2020,

title = {Aerosol retrievals from the EKO MS-711 spectral direct irradiance measurements and corrections of the circumsolar radiation},

author = {R. D. García-Cabrera and E. Cuevas-Agulló and Á. Barreto and V. E. Cachorro and M. Pó and R. Ramos and K. Hoogendijk},

url = {https://amt.copernicus.org/articles/13/2601/2020/},

doi = {10.5194/amt-13-2601-2020},

year  = {2020},

date = {2020-05-20},

urldate = {2020-01-01},

journal = {Atmospheric Measurement Techniques},

volume = {13},

number = {5},

pages = {2601--2621},

keywords = {aerosol optical depth, langley, Solar radiation, spectroradiometer, UV-visible irradiance},

pubstate = {published},

tppubtype = {article}

}