{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,13]],"date-time":"2026-01-13T01:08:23Z","timestamp":1768266503087,"version":"3.49.0"},"reference-count":43,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,2,8]],"date-time":"2020-02-08T00:00:00Z","timestamp":1581120000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100014440","name":"Ministerio de Ciencia, Innovaci\u00f3n y Universidades","doi-asserted-by":"publisher","award":["IJCI-2017-33856"],"award-info":[{"award-number":["IJCI-2017-33856"]}],"id":[{"id":"10.13039\/100014440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014440","name":"Ministerio de Ciencia, Innovaci\u00f3n y Universidades","doi-asserted-by":"publisher","award":["RTI2018-097957-B-C31"],"award-info":[{"award-number":["RTI2018-097957-B-C31"]}],"id":[{"id":"10.13039\/100014440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100014440","name":"Ministerio de Ciencia, Innovaci\u00f3n y Universidades","doi-asserted-by":"publisher","award":["RTI2018-097957-B-C33"],"award-info":[{"award-number":["RTI2018-097957-B-C33"]}],"id":[{"id":"10.13039\/100014440","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Comunidad de Madrid and FEDER program","award":["SINFOTON2-CM: P2018\/NMT-4326"],"award-info":[{"award-number":["SINFOTON2-CM: P2018\/NMT-4326"]}]},{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["FINESSE, MSCA-ITN-ETN-722509"],"award-info":[{"award-number":["FINESSE, MSCA-ITN-ETN-722509"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Until recently, the amount of solar irradiance reaching the Earth surface was considered to be a steady value over the years. However, there is increasing observational evidence showing that this quantity undergoes substantial variations over time, which need to be addressed in different scenarios ranging from climate change to solar energy applications. With the growing interest in developing solar energy technology with enhanced efficiency and optimized management, the monitoring of solar irradiance at the ground level is now considered to be a fundamental input in the pursuit of that goal. Here, we propose the first fiber-based distributed sensor able of monitoring ground solar irradiance in real time, with meter scale spatial resolutions over distances of several tens of kilometers (up to 100 km). The technique is based on an optical fiber reflectometry technique (CP-\u03d5OTDR), which enables real time and long-range high-sensitivity bolometric measurements of solar radiance with a single optical fiber cable and a single interrogator unit. The method is explained and analyzed theoretically. A validation of the method is proposed using a solar simulator irradiating standard optical fibers, where we demonstrate the ability to detect and quantify solar irradiance with less than a 0.1 W\/m2 resolution.<\/jats:p>","DOI":"10.3390\/s20030908","type":"journal-article","created":{"date-parts":[[2020,2,10]],"date-time":"2020-02-10T11:48:51Z","timestamp":1581335331000},"page":"908","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Long-Range Distributed Solar Irradiance Sensing Using Optical Fibers"],"prefix":"10.3390","volume":"20","author":[{"given":"Regina","family":"Magalh\u00e3es","sequence":"first","affiliation":[{"name":"Dpto. de Electr\u00f3nica, Universidad de Alcal\u00e1, 28805 Alcal\u00e1 de Henares (Madrid), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luis","family":"Costa","sequence":"additional","affiliation":[{"name":"Dpto. de Electr\u00f3nica, Universidad de Alcal\u00e1, 28805 Alcal\u00e1 de Henares (Madrid), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sonia","family":"Martin-Lopez","sequence":"additional","affiliation":[{"name":"Dpto. de Electr\u00f3nica, Universidad de Alcal\u00e1, 28805 Alcal\u00e1 de Henares (Madrid), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miguel","family":"Gonzalez-Herraez","sequence":"additional","affiliation":[{"name":"Dpto. de Electr\u00f3nica, Universidad de Alcal\u00e1, 28805 Alcal\u00e1 de Henares (Madrid), Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2125-8495","authenticated-orcid":false,"given":"Alejandro F.","family":"Bra\u00f1a","sequence":"additional","affiliation":[{"name":"Grupo de Electr\u00f3nica y Semiconductores, Dpto. de F\u00edsica Aplicada, Universidad Aut\u00f3noma de Madrid, 28049 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3927-8125","authenticated-orcid":false,"given":"Hugo F.","family":"Martins","sequence":"additional","affiliation":[{"name":"Instituto de \u00d3ptica, Consejo Superior de Investigaciones Cient\u00edficas, 28006 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.rser.2012.12.033","article-title":"Comparative assessment of global irradiation from a satellite estimate model (CM SAF) and on-ground measurements (SIAR): A Spanish case study","volume":"21","year":"2013","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"D00D16","DOI":"10.1029\/2008JD011470","article-title":"Global dimming and brightening: A review","volume":"114","author":"Wild","year":"2009","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.solener.2016.03.001","article-title":"Preliminary survey on site-adaptation techniques for satellite-derived and reanalysis solar radiation datasets","volume":"132","author":"Polo","year":"2019","journal-title":"Solar Energy"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1016\/S0034-4257(03)00083-X","article-title":"Solar energy assessment using remote sensing technologies","volume":"86","author":"Hammer","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"985","DOI":"10.1016\/j.renene.2019.05.075","article-title":"Short-term forecasting of solar irradiance","volume":"143","author":"Paulescu","year":"2019","journal-title":"Renew. Energy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1016\/j.renene.2016.12.095","article-title":"Machine learning methods for solar radiation forecasting: A review","volume":"105","author":"Voyant","year":"2017","journal-title":"Renew. Energy"},{"key":"ref_7","unstructured":"Heinemann, D., Lorenz, E., and Girodo, M. (2006). Forecasting of solar radiation. Solar Energy Resource Management for Electricity Generation from Local Level to Global Scale, Nova Science Publishers."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Polo, J., Zarzalejo, L.F., and Ram\u00edrez, L. (2008). Solar radiation derived from satellite images. Modeling Solar Radiation at the Earth\u2019s Surface, Springer.","DOI":"10.1007\/978-3-540-77455-6_18"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"480","DOI":"10.1016\/j.solener.2008.09.006","article-title":"A new statistical approach for deriving global solar radiation from satellite images","volume":"83","author":"Zarzalejo","year":"2009","journal-title":"Solar Energy"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2934","DOI":"10.1109\/TGRS.2011.2178855","article-title":"An advanced model for the estimation of the surface solar irradiance under all atmospheric conditions using MSG\/SEVIRI data","volume":"50","author":"Geraldi","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/S0038-092X(96)00162-4","article-title":"Comparing satellite remote sensing and ground network measurements for the production of site\/time specific irradiance data","volume":"60","author":"Perez","year":"1997","journal-title":"Sol. Energy"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"342","DOI":"10.1016\/j.solener.2008.08.007","article-title":"Predicting solar radiation at high resolutions: A comparison of time series forecasts","volume":"83","author":"Reikard","year":"2009","journal-title":"Sol. Energy"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1175\/1520-0493(1968)096<0237:MSOGRA>2.0.CO;2","article-title":"Mesoscale sampling of global radiation analysis of data from Wisconsin","volume":"96","author":"Kerr","year":"1968","journal-title":"Mon. Wea. Rev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1175\/1520-0450(1995)034<1039:SMOSIA>2.0.CO;2","article-title":"Surface measurements of solar irradiance: A study of the spatial correlation between simultaneous measurements at separated sites","volume":"34","author":"Long","year":"1995","journal-title":"J. Appl. Meteorol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1175\/1520-0450(1983)022<0488:EOSRMM>2.0.CO;2","article-title":"Extrapolation of solar radiation measurements: Mesoscale analyses from Arizona and Tennessee Valley Authority regions","volume":"22","author":"Suckling","year":"1983","journal-title":"J. Clim. Appl. Meteorol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1016\/0038-092X(85)90117-3","article-title":"Estimating daily solar radiation values in selected mid-latitude regions by extrapolating measurements from nearby stations","volume":"35","author":"Suckling","year":"1985","journal-title":"Sol. Energy"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/0168-1923(94)90067-1","article-title":"Spatial variability of daily weather variables in the high plains of the USA","volume":"68","author":"Hubbard","year":"1994","journal-title":"Agric. For. Meteorol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1085","DOI":"10.1175\/1520-0450(2001)040<1085:DOSMTK>2.0.CO;2","article-title":"Determination of semivariogram models to krige hourly and daily solar irradiance in western Nebraska","volume":"40","author":"Merino","year":"2001","journal-title":"J. Appl. Meteorol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1713","DOI":"10.1016\/j.rser.2015.07.134","article-title":"Forecasting for dynamic line rating","volume":"52","author":"Michiorri","year":"2015","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2154","DOI":"10.1109\/TPWRD.2014.2376275","article-title":"Key considerations for the selection of dynamic thermal line rating systems","volume":"30","author":"Black","year":"2014","journal-title":"IEEE Trans. Power Deliv."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1016\/j.solener.2019.06.007","article-title":"Evaluation of solar irradiance forecasting skills of the Australian Bureau of Meteorology\u2019s ACCESS models","volume":"188","author":"Joshi","year":"2019","journal-title":"Sol. Energy"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1109\/JSEN.2011.2162060","article-title":"Distributed temperature sensing: Review of technology and applications","volume":"12","author":"Ukil","year":"2011","journal-title":"IEEE Sens. J."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"W12202","DOI":"10.1029\/2006WR005326","article-title":"Distributed fiber-optic temperature sensing for hydrologic systems","volume":"42","author":"Selker","year":"2006","journal-title":"Water Resour. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1038","DOI":"10.1364\/OL.15.001038","article-title":"Distributed-temperature sensing using stimulated Brillouin scattering in optical silica fibers","volume":"15","author":"Kurashima","year":"1990","journal-title":"Opt. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4496","DOI":"10.1109\/JLT.2019.2904756","article-title":"Distributed hydrostatic pressure measurement using phase OTDR in a highly birefringent photonic crystal fiber","volume":"37","author":"Mikhailov","year":"2019","journal-title":"J. Lightwave Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1064","DOI":"10.1364\/OL.37.001064","article-title":"Distributed high-temperature pressure sensing using air-hole microstructural fibers","volume":"37","author":"Chen","year":"2012","journal-title":"Opt. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"21399","DOI":"10.1364\/OE.24.021399","article-title":"Distributed measurement of hydrostatic pressure based on Brillouin dynamic grating in polarization maintaining fibers","volume":"24","author":"Kim","year":"2016","journal-title":"Opt. Express"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5372","DOI":"10.1364\/AO.38.005372","article-title":"Simultaneous distributed strain and temperature measurement","volume":"38","author":"Smith","year":"1999","journal-title":"Appl. Opt."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Garcia-Ruiz, A., Martins, H.F., Pastor-Graells, J., Martin-Lopez, S., and Gonzalez-Herraez, M. (2016, January 11\u201314). Single-Shot true distributed strain variation measurements over> 10 km using phase-sensitive OTDR with chirped pulses. Proceedings of the Asia-Pacific Optical Sensors Conference, Shanghai, China.","DOI":"10.1364\/APOS.2016.Th3A.2"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1884","DOI":"10.1109\/LPT.2015.2444419","article-title":"Distributed strain and vibration sensing system based on phase-sensitive OTDR","volume":"27","author":"Zhou","year":"2015","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"8601","DOI":"10.3390\/s120708601","article-title":"Recent progress in distributed fiber optic sensors","volume":"12","author":"Bao","year":"2012","journal-title":"Sensors"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Barrias, A., Casas, J.R., and Villalba, S. (2016). A review of distributed optical fiber sensors for civil engineering applications. Sensors, 16.","DOI":"10.3390\/s16050748"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Magalh\u00e3es, R., Pereira, J., Garcia-Ruiz, A., Margulis, W., Martin-Lopez, S., Gonzalez-Herraez, M., and Martins, H.F. (2019, January 1\u20134). Distributed detection of quadratic Kerr effect in silica fibers using chirped-pulse \u03a6OTDR. Proceedings of the Seventh European Workshop on Optical Fibre Sensors, Limassol, Cyprus.","DOI":"10.1117\/12.2540755"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Fern\u00e1ndez-Ruiz, M.R., Williams, E.L., Magalhaes, R., Vanthillo, R., Costa, L., Zhan, Z., Martin-Lopez, S., Gonzalez-Herraez, M., and Martins, H.F. (2019, January 1\u20134). Teleseisms monitoring using chirped-pulse \u03a6OTDR. Proceedings of the Seventh European Workshop on Optical Fibre Sensors, Limassol, Cyprus.","DOI":"10.1117\/12.2539966"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1111\/j.1467-8667.2006.00446.x","article-title":"Health monitoring of rehabilitated concrete bridges using distributed optical fiber sensing","volume":"21","author":"Zhang","year":"2006","journal-title":"Comput. Aided Civ. Infrastruct. Eng."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"11620","DOI":"10.1038\/s41598-017-11986-4","article-title":"Distributed acoustic sensing for seismic monitoring of the near surface: A traffic-noise interferometry case study","volume":"7","author":"Dou","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1142","DOI":"10.1109\/JLT.2008.928957","article-title":"Fiber-optic distributed strain and temperature sensing with very high measurand resolution over long range using coherent OTDR","volume":"27","author":"Koyamada","year":"2009","journal-title":"J. Lightwave Technol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"13121","DOI":"10.1364\/OE.24.013121","article-title":"Single-shot distributed temperature and strain tracking using direct detection phase-sensitive OTDR with chirped pulses","volume":"24","author":"Martins","year":"2016","journal-title":"Opt. Express"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Fern\u00e1ndez-Ruiz, M.R., Costa, L., and Martins, H.F. (2019). Distributed Acoustic Sensing Using Chirped-Pulse Phase-Sensitive OTDR Technology. Sensors, 19.","DOI":"10.3390\/s19204368"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"4317","DOI":"10.1364\/OE.27.004317","article-title":"Fiber-based distributed bolometry","volume":"27","author":"Martins","year":"2019","journal-title":"Opt. Express"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1789","DOI":"10.1364\/OE.25.001789","article-title":"Distributed photothermal spectroscopy in microstructured optical fibers: Towards high-resolution mapping of gas presence over long distances","volume":"25","author":"Martins","year":"2017","journal-title":"Opt. Express"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"24923","DOI":"10.1364\/OE.23.024923","article-title":"Distributed phase birefringence measurements based on polarization correlation in phase-sensitive optical time-domain reflectometers","volume":"23","author":"Soto","year":"2015","journal-title":"Opt. Express"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"4487","DOI":"10.1109\/JLT.2019.2904560","article-title":"Fully distributed optical fiber strain sensor with 10\u201312 \u03b5\/\u221aHz sensitivity","volume":"37","author":"Costa","year":"2019","journal-title":"J. Lightwave Technol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/3\/908\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:55:56Z","timestamp":1760172956000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/3\/908"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,8]]},"references-count":43,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["s20030908"],"URL":"https:\/\/doi.org\/10.3390\/s20030908","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,8]]}}}