{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,19]],"date-time":"2025-12-19T09:51:09Z","timestamp":1766137869262,"version":"build-2065373602"},"reference-count":50,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2021,12,19]],"date-time":"2021-12-19T00:00:00Z","timestamp":1639872000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>We propose a methodological approach to provide the accurate and calibrated measurements of sky radiance and broadband solar irradiance using the High Dynamic Range (HDR) images of a sky-camera. This approach is based on a detailed instrumental characterization of a SONA sky-camera in terms of image acquisition and processing, as well as geometric and radiometric calibrations. As a result, a 1 min time resolution database of geometrically and radiometrically calibrated HDR images has been created and has been available since February 2020, with daily updates. An extensive validation of our radiometric retrievals has been performed in all sky conditions. Our results show a very good agreement with the independent measurements of the AERONET almucantar for sky radiance and pyranometers for broadband retrievals. The SONA sky radiance shows a difference of an RMBD &lt; 10% while the broadband diffuse radiation shows differences of 2% and 5% over a horizontal plane and arbitrarily oriented surfaces, respectively. These results support the developed methodology and allow us to glimpse the great potential of sky-cameras to carry out accurate measurements of sky radiance and solar radiation components. Thus, the remote sensing techniques described here will undoubtedly be of great help for solar and atmospheric research.<\/jats:p>","DOI":"10.3390\/rs13245157","type":"journal-article","created":{"date-parts":[[2021,12,20]],"date-time":"2021-12-20T02:40:32Z","timestamp":1639968032000},"page":"5157","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Feasibility of Ground-Based Sky-Camera HDR Imagery to Determine Solar Irradiance and Sky Radiance over Different Geometries and Sky Conditions"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8235-3771","authenticated-orcid":false,"given":"Pedro","family":"Valdelomar","sequence":"first","affiliation":[{"name":"Departament de F\u00edsica de la Terra i Termodin\u00e0mica, Universitat de Val\u00e8ncia, 46100 Burjassot, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7543-9163","authenticated-orcid":false,"given":"Jos\u00e9 L.","family":"G\u00f3mez-Amo","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica de la Terra i Termodin\u00e0mica, Universitat de Val\u00e8ncia, 46100 Burjassot, Spain"}]},{"given":"Caterina","family":"Peris-Ferr\u00fas","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica de la Terra i Termodin\u00e0mica, Universitat de Val\u00e8ncia, 46100 Burjassot, Spain"}]},{"given":"Francesco","family":"Scarlatti","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica de la Terra i Termodin\u00e0mica, Universitat de Val\u00e8ncia, 46100 Burjassot, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1952-4117","authenticated-orcid":false,"given":"Mar\u00eda Pilar","family":"Utrillas","sequence":"additional","affiliation":[{"name":"Departament de F\u00edsica de la Terra i Termodin\u00e0mica, Universitat de Val\u00e8ncia, 46100 Burjassot, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,19]]},"reference":[{"key":"ref_1","unstructured":"IEA (2017). World Energy Outlook 2017, International Energy Agency and Organisation for Economic Co-operation and Development OECD."},{"key":"ref_2","unstructured":"Tsiropoulos, I., Nijs, W., Tarvydas, D., and Ruiz Castello, P. (2020). Towards Net-Zero Emissions in the EU Energy System by 2050, Publications Office of the European Union. EUR 29981 EN."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3101","DOI":"10.1039\/c1ee01495a","article-title":"Climate change impacts on future photovoltaic and concentrated solar power energy output","volume":"4","author":"Crook","year":"2011","journal-title":"Energy Environ. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"706","DOI":"10.1016\/j.rser.2014.07.041","article-title":"The near future availability of photovoltaic energy in Europe and Africa in climate-aerosol modeling experiments","volume":"38","author":"Gaetani","year":"2014","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"111726","DOI":"10.1016\/j.enpol.2020.111726","article-title":"An ecological macroeconomics model: The energy transition in the EU","volume":"145","author":"Nieto","year":"2020","journal-title":"Energy Policy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1166","DOI":"10.1016\/j.enconman.2015.09.001","article-title":"Solar irradiance forecasting at one-minute intervals for different sky conditions using sky camera images","volume":"105","author":"Batlles","year":"2015","journal-title":"Energy Convers. Manag."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2115","DOI":"10.1175\/1520-0477(1998)079<2115:BSRNBW>2.0.CO;2","article-title":"Baseline Surface Radiation Network (BSRN\/WCRP): New Precision Radiometry for Climate Research","volume":"79","author":"Ohmura","year":"1998","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Nowak, D., Vuilleumier, L., Long, C.N., and Ohmura, A. (2008). Solar irradiance computations compared with observations at the Baseline Surface Radiation Network Payerne site. J. Geophys. Res. Space Phys., 113.","DOI":"10.1029\/2007JD009441"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"15609","DOI":"10.1029\/2000JD900077","article-title":"Identification of clear skies from broadband pyranometer measurements and calculation of downwelling shortwave cloud effects","volume":"105","author":"Long","year":"2000","journal-title":"J. Geophys. Res. Space Phys."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1057","DOI":"10.1175\/1520-0450(2004)043<1057:ASEETC>2.0.CO;2","article-title":"A Simple Empirical Equation to Calculate Cloud Optical Thickness Using Shortwave Broadband Measurements","volume":"43","author":"Barnard","year":"2004","journal-title":"J. Appl. Meteorol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Long, C.N., Ackerman, T.P., Gaustad, K.L., and Cole, J.N.S. (2006). Estimation of fractional sky cover from broadband shortwave radiometer measurements. J. Geophys. Res. Space Phys., 111.","DOI":"10.1029\/2005JD006475"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1016\/j.renene.2009.07.018","article-title":"Modelling of diffuse solar fraction with multiple predictors","volume":"35","author":"Ridley","year":"2010","journal-title":"Renew. Energy"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"558","DOI":"10.1016\/j.solener.2017.05.018","article-title":"Improving the separation of direct and diffuse solar radiation components using machine learning by gradient boosting","volume":"150","author":"Aler","year":"2017","journal-title":"Sol. Energy"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.solener.2013.05.005","article-title":"Comparison of numerical weather prediction solar irradiance forecasts in the US, Canada and Europe","volume":"94","author":"Perez","year":"2013","journal-title":"Sol. Energy"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.renene.2016.06.042","article-title":"Comparison of satellite imagery based data, reanalysis data and statistical methods for mapping global solar radiation in the Lerma Valley (Salta, Argentina)","volume":"99","author":"Camargo","year":"2016","journal-title":"Renew. Energy"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Kim, C.K., Kim, H.-G., Kang, Y.-H., Yun, C.-Y., and Lee, Y.G. (2020). Intercomparison of Satellite-Derived Solar Irradiance from the GEO-KOMSAT-2A and HIMAWARI-8\/9 Satellites by the Evaluation with Ground Observations. Remote Sens., 12.","DOI":"10.3390\/rs12132149"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"163","DOI":"10.5194\/hess-17-163-2013","article-title":"Validation of a Meteosat Second Generation solar radiation dataset over the northeastern Iberian Peninsula","volume":"17","author":"Anderson","year":"2013","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2340","DOI":"10.1002\/jgrd.50194","article-title":"Retrieval and validation of global, direct, and diffuse irradiance derived from SEVIRI satellite observations","volume":"118","author":"Greuell","year":"2013","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1016\/j.energy.2015.07.028","article-title":"The use of a sky camera for solar radiation estimation based on digital image processing","volume":"90","author":"Batlles","year":"2015","journal-title":"Energy"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"4151","DOI":"10.5194\/amt-9-4151-2016","article-title":"Coupling sky images with radiative transfer models: A new method to estimate cloud optical depth","volume":"9","author":"Mejia","year":"2016","journal-title":"Atmos. Meas. Tech."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5519","DOI":"10.5194\/amt-12-5519-2019","article-title":"ELIFAN, an algorithm for the estimation of cloud cover from sky imagers","volume":"12","author":"Lothon","year":"2019","journal-title":"Atmos. Meas. Tech."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1953","DOI":"10.5194\/amt-13-1953-2020","article-title":"SegCloud: A novel cloud image segmentation model using a deep convolutional neural network for ground-based all-sky-view camera observation","volume":"13","author":"Xie","year":"2020","journal-title":"Atmos. Meas. Tech."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2013","DOI":"10.5194\/amt-5-2013-2012","article-title":"Calibration of an all-sky camerasky-camera for obtaining sky-radiance at three wavelengths","volume":"5","author":"Cazorla","year":"2012","journal-title":"Atmos. Meas. Tech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2739","DOI":"10.1016\/j.atmosenv.2007.06.016","article-title":"Using a Sky Imager for aerosol characterization","volume":"42","author":"Cazorla","year":"2008","journal-title":"Atmos. Environ."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2881","DOI":"10.5194\/amt-5-2881-2012","article-title":"A method for cloud detection and opacity classification based on ground based sky imagery","volume":"5","author":"Ghonima","year":"2012","journal-title":"Atmos. Meas. Tech."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1016\/j.rse.2017.05.013","article-title":"Remote sensing of lunar aureole with a sky camera: Adding information in the nocturnal retrieval of aerosol properties with GRASP code","volume":"196","author":"Torres","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Rom\u00e1n, R., Antu\u00f1a-S\u00e1nchez, J.C., Cachorro, V.E., Toledano, C., Torres, B., Mateos, D., Fuertes, D., L\u00f3pez, C., Gonz\u00e1lez, R., and Lapionok, T. (2021). Retrieval of aerosol properties using relative radiance measurements from an all-sky camera. Atmos. Meas. Tech. Discuss.","DOI":"10.5194\/amt-2021-204"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.solener.2015.01.024","article-title":"Real-time forecasting of solar irradiance ramps with smart image processing","volume":"114","author":"Chu","year":"2015","journal-title":"Sol. Energy"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1016\/j.solener.2016.11.032","article-title":"Measuring diffuse, direct, and global irradiance using a sky imager","volume":"141","author":"Kurtz","year":"2017","journal-title":"Sol. Energy"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1225","DOI":"10.1016\/j.solener.2018.08.042","article-title":"Local estimation of the global horizontal irradiance using an all-sky camera","volume":"173","author":"Scolari","year":"2018","journal-title":"Sol. Energy"},{"key":"ref_31","first-page":"D11201","article-title":"Columnar aerosol properties in Valencia (Spain) by ground-based Sun photometry","volume":"112","author":"Utrillas","year":"2007","journal-title":"J. Geophys. Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.atmosenv.2016.01.008","article-title":"Multiyear in-situ measurements of atmospheric aerosol absorption properties at an urban coastal site in western Mediterranean","volume":"129","author":"Segura","year":"2016","journal-title":"Atmos. Environ."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1016\/j.atmosres.2018.06.016","article-title":"Analysis of four years of ceilometer-derived aerosol backscatter profiles in a coastal site of the western Mediterranean","volume":"213","author":"Marcos","year":"2018","journal-title":"Atmos. Res."},{"key":"ref_34","first-page":"2121","article-title":"Impact of dust and smoke mixing on column-integrated aerosol properties from observations during a severe wildfire episode over Valencia (Spain)","volume":"599\u2013600","author":"Marcos","year":"2017","journal-title":"Sci. Total Environ."},{"key":"ref_35","first-page":"1226","article-title":"Empirical estimates of the radiative impact of an unusually extreme dust and wildfire episode on the performance of a photovoltaic plant in Western Mediterranean","volume":"235","author":"Camarasa","year":"2018","journal-title":"Appl. Energy"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0034-4257(98)00031-5","article-title":"AERONET\u2014A Federated Instrument Network and Data Archive for Aerosol Characterization","volume":"66","author":"Holben","year":"1998","journal-title":"Remote Sens. Environ."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"11619","DOI":"10.5194\/acp-12-11619-2012","article-title":"AERONET and ESR sun direct products comparison performed on Cimel CE318 and Prede POM01 solar radiometers","volume":"12","author":"Campanelli","year":"2012","journal-title":"Atmos. Chem. Phys."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"590","DOI":"10.1175\/1520-0469(2002)059<0590:VOAAOP>2.0.CO;2","article-title":"Variability of absorption and optical properties of key aerosol types observed in worldwide locations","volume":"59","author":"Dubovik","year":"2002","journal-title":"J. Atmos. Sci."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"516","DOI":"10.1086\/300408","article-title":"The International Celestial Reference Frame as Realized by Very Long Baseline Interferometry","volume":"116","author":"Ma","year":"1998","journal-title":"Astron. J."},{"key":"ref_40","first-page":"628","article-title":"The theory of perspective","volume":"116","author":"Cox","year":"1969","journal-title":"Br. J. Photogr."},{"key":"ref_41","first-page":"374","article-title":"Recovering high dynamic range radiance maps from photographs","volume":"1","author":"Debevec","year":"2003","journal-title":"SIGGRAPH"},{"key":"ref_42","unstructured":"Mitsunaga, T., and Nayar, S. (1999, January 23\u201325). Radiometric self calibration. Proceedings of the 1999 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (Cat. No PR00149), Fort Collins, CO, USA."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2201","DOI":"10.5194\/amt-14-2201-2021","article-title":"Relative sky-radiance from multi-exposure all-sky camerasky-camera images","volume":"14","author":"Cachorro","year":"2021","journal-title":"Atmos. Meas. Tech."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1647","DOI":"10.5194\/gmd-9-1647-2016","article-title":"The libRadtran software package for radiative transfer calculations (version 2.0.1)","volume":"9","author":"Emde","year":"2016","journal-title":"Geosci. Model Dev."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1146","DOI":"10.1007\/BF00611771","article-title":"Calculation of the effective wavelength of a measuring system","volume":"23","author":"Kholopov","year":"1975","journal-title":"J. Appl. Spectrosc."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1086\/144246","article-title":"Diffuse radiation in the Galaxy","volume":"93","author":"Henyey","year":"1941","journal-title":"Astrophys. J."},{"key":"ref_47","unstructured":"Vermeulen, A. (1996). Caract\u00e9risation des A\u00e9rosols \u00e1 Partir de Mesures Optiques Passives au Sol: Apport des Luminances Totale et Polaris\u00e9e Mesur\u00e9es dans le Plan Principal. [Ph.D. Thesis, Universit\u00e9 de Lille]."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"2207","DOI":"10.5194\/amt-6-2207-2013","article-title":"Measurements on pointing error and field of view of Cimel-318 Sun photometers in the scope of AERONET","volume":"6","author":"Torres","year":"2013","journal-title":"Atmos. Meas. Tech."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1016\/j.solener.2014.10.001","article-title":"Direct normal irradiance related definitions and applications: The circumsolar issue","volume":"110","author":"Blanc","year":"2014","journal-title":"Sol. Energy"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/0038-092X(92)90098-U","article-title":"Estimation of the error caused by the circumsolar radiation when measuring global radiation as a sum of direct and diffuse radiation","volume":"48","author":"Major","year":"1992","journal-title":"Sol. Energy"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/24\/5157\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:51:49Z","timestamp":1760169109000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/24\/5157"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,19]]},"references-count":50,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2021,12]]}},"alternative-id":["rs13245157"],"URL":"https:\/\/doi.org\/10.3390\/rs13245157","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2021,12,19]]}}}