{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:13:12Z","timestamp":1760148792977,"version":"build-2065373602"},"reference-count":65,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2023,6,12]],"date-time":"2023-06-12T00:00:00Z","timestamp":1686528000000},"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>Cloud cover is important meteorological information that still requires expensive equipment to be monitored from the ground, especially at night. The use of artificial lights at night causes light pollution, and clouds amplify this by reflecting light downward. In addition, cloud thermal radiation emissions affect sky temperature. In this study, we describe a system (NSKY-CD) that can be used to detect clouds at night since it integrates a sky quality meter that measures night sky brightness (NSB) and an air temperature and an infrared temperature sensor that measure sky temperature. We defined a cloud detection method based on fixed threshold values determined with two different procedures that we called \u2018optimal\u2019 and \u2018antimode\u2019. We then quantitatively assessed the performance of these methods in detecting the presence or absence of clouds in the urban area of Florence during two full moon cycles. Accuracy for the \u2018optimal\u2019 method varied between 87% and 91%, while for the \u2018antimode\u2019 method, it varied between 86% and 89%. Our results suggest that the two parameters are complementary since NSB has a better performance on moonless nights, and the difference between air temperature and sky temperature has a better performance on moonlit nights. Our method can also be used to analyze historical series of NSB to estimate cloud presence backwards, thus providing important information for meteorological, environmental and astronomical studies.<\/jats:p>","DOI":"10.3390\/rs15123063","type":"journal-article","created":{"date-parts":[[2023,6,12]],"date-time":"2023-06-12T01:59:07Z","timestamp":1686535147000},"page":"3063","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["NSKY-CD: A System for Cloud Detection Based on Night Sky Brightness and Sky Temperature"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0941-5347","authenticated-orcid":false,"given":"Luciano","family":"Massetti","sequence":"first","affiliation":[{"name":"Institute of Bioeconomy of the National Research Council, 50019 Sesto Fiorentino, Italy"}]},{"given":"Alessandro","family":"Materassi","sequence":"additional","affiliation":[{"name":"Institute of Bioeconomy of the National Research Council, 50019 Sesto Fiorentino, Italy"}]},{"given":"Francesco","family":"Sabatini","sequence":"additional","affiliation":[{"name":"Institute of Bioeconomy of the National Research Council, 50019 Sesto Fiorentino, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2023,6,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8409","DOI":"10.1038\/srep08409","article-title":"Worldwide variations in artificial skyglow","volume":"5","author":"Kyba","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e1600377","DOI":"10.1126\/sciadv.1600377","article-title":"The new world atlas of artificial night sky brightness","volume":"2","author":"Falchi","year":"2016","journal-title":"Sci. Adv."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1177\/1477153513506729","article-title":"The relation of outdoor lighting characteristics to sky glow from distant cities","volume":"46","author":"Duriscoe","year":"2014","journal-title":"Light. Res. Technol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1098\/rsos.201501","article-title":"A linear systems approach to protect the night sky: Implications for current and future regulations","volume":"7","author":"Falchi","year":"2020","journal-title":"R. Soc. Open Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1132","DOI":"10.1111\/cobi.12462","article-title":"Quantifying the erosion of natural darkness in the global protected area system: Decline of darkness within protected areas","volume":"29","author":"Gaston","year":"2015","journal-title":"Conserv. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"20160813","DOI":"10.1098\/rspb.2016.0813","article-title":"Light pollution is associated with earlier tree budburst across the United Kingdom","volume":"283","author":"Bennie","year":"2016","journal-title":"Proc. R. Soc. B Biol. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1111\/1365-2745.12551","article-title":"Ecological effects of artificial light at night on wild plants","volume":"104","author":"Bennie","year":"2016","journal-title":"J. Ecol."},{"key":"ref_8","first-page":"282","article-title":"Effects of light pollution on tree phenology in the urban environment","volume":"25","year":"2017","journal-title":"Morav. Geogr. Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2698","DOI":"10.1111\/1365-2664.13240","article-title":"Artificial light at night causes top-down and bottom-up trophic effects on invertebrate populations","volume":"55","author":"Bennie","year":"2018","journal-title":"J. Appl. Ecol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.ocecoaman.2017.12.013","article-title":"Reduction of sea turtle population recruitment caused by nightlight: Evidence from the Mediterranean region","volume":"153","author":"Dimitriadis","year":"2018","journal-title":"Ocean Coast. Manag."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.ufug.2018.05.015","article-title":"Assessing the impact of street lighting on Platanus x acerifolia phenology","volume":"34","author":"Massetti","year":"2018","journal-title":"Urban For. Urban Green."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Grubisic, M., Haim, A., Bhusal, P., Dominoni, D.M., Gabriel, K.M.A., Jechow, A., Kupprat, F., Lerner, A., Marchant, P., and Riley, W. (2019). Light pollution, circadian photoreception, and melatonin in vertebrates. Sustainability, 11.","DOI":"10.3390\/su11226400"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1111\/aab.12440","article-title":"Insect declines and agroecosystems: Does light pollution matter? Insect declines and agroecosystems","volume":"173","author":"Grubisic","year":"2018","journal-title":"Ann. Appl. Biol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"694","DOI":"10.1111\/1365-2435.13485","article-title":"Artificial light at night erases positive interactions across trophic levels","volume":"34","author":"Maggi","year":"2020","journal-title":"Funct. Ecol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113314","DOI":"10.1016\/j.envpol.2019.113314","article-title":"Multisensory pollution: Artificial light at night and anthropogenic noise have interactive effects on activity patterns of great tits (Parus major)","volume":"256","author":"Dominoni","year":"2020","journal-title":"Environ. Pollut."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"114206","DOI":"10.1016\/j.envpol.2020.114206","article-title":"Light pollution disrupts molecular clock in avian species: A power-calibrated meta-analysis","volume":"265","author":"Yang","year":"2020","journal-title":"Environ. Pollut."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"20140121","DOI":"10.1098\/rstb.2014.0121","article-title":"Artificial light at night: Melatonin as a mediator between the environment and epigenome","volume":"370","author":"Haim","year":"2015","journal-title":"Philos. Trans. R. Soc. B Biol. Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1016\/j.lfs.2017.02.008","article-title":"Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption","volume":"173","author":"Touitou","year":"2017","journal-title":"Life Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1725","DOI":"10.1007\/s10980-020-01053-1","article-title":"The impact of artificial light at night on human and ecosystem health: A systematic literature review","volume":"35","author":"Svechkina","year":"2020","journal-title":"Landsc. Ecol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/j.rse.2016.02.017","article-title":"Quantifying urban light pollution-A comparison between field measurements and EROS-B imagery","volume":"177","author":"Katz","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"111443","DOI":"10.1016\/j.rse.2019.111443","article-title":"Remote sensing of night lights: A review and an outlook for the future","volume":"237","author":"Levin","year":"2020","journal-title":"Remote Sens. Environ."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Barentine, J.C., Walczak, K., Gyuk, G., Tarr, C., and Longcore, T. (2021). A case for a new satellite mission for remote sensing of night lights. Remote Sens., 13.","DOI":"10.3390\/rs13122294"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.jqsrt.2016.04.027","article-title":"Urban artificial light emission function determined experimentally using night sky images","volume":"181","author":"Kocifaj","year":"2016","journal-title":"J. Quant. Spectro. Radiat. Trans."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"61","DOI":"10.26607\/ijsl.v19i1.70","article-title":"Night sky quality monitoring in existing and planned dark sky parks by digital cameras","volume":"19","year":"2017","journal-title":"Int. J. Sustain. Light"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.jqsrt.2018.01.032","article-title":"Tracking the dynamics of skyglow with differential photometry using a digital camera with fisheye lens","volume":"209","author":"Jechow","year":"2018","journal-title":"J. Quant. Spectrosc. Radiat. Transf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1391","DOI":"10.1038\/s41598-018-37817-8","article-title":"Using all-sky differential photometry to investigate how nocturnal clouds darken the night sky in rural areas","volume":"9","author":"Jechow","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"32","DOI":"10.26607\/ijsl.v18i0.19","article-title":"How clouds are amplifying (or not) the effects of ALAN","volume":"35","author":"Ribas","year":"2016","journal-title":"Int. J. Sustain. Light."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.jqsrt.2018.03.010","article-title":"Systematic measurements of the night sky brightness at 26 locations in Eastern Austria","volume":"211","author":"Posch","year":"2018","journal-title":"J. Quant. Spectro. Radiat. Trans."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Bar\u00e1, S., Lima, R.C., and Zamorano, J. (2019). Monitoring long-term trends in the anthropogenic night sky brightness. Sustainability, 11.","DOI":"10.3390\/su11113070"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Bertolo, A., Binotto, R., Ortolani, S., and Sapienza, S. (2019). Measurements of night sky brightness in the Veneto Region of Italy: Sky quality meter network results and differential photometry by digital single lens reflex. J. Imaging, 5.","DOI":"10.3390\/jimaging5050056"},{"key":"ref_31","unstructured":"Montesinos, B., Asensio Ramos, A., Buitrago, F., Sch\u00f6del, R., Villaver, E., P\u00e9rez-Hoyos, S., and Ord\u00f3\u00f1ez-Etxeberria, I. (2019). Highlights on Spanish Astrophysics X, Proceedings of the XIII Scientific Meeting of the Spanish Astronomical Society, Salamanca, Spain, 16\u201320 July 2018, Sociedad Espa\u00f1ola de Astronomia."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"107250","DOI":"10.1016\/j.jqsrt.2020.107250","article-title":"Drivers of artificial light at night variability in urban, rural and remote areas","volume":"255","author":"Massetti","year":"2020","journal-title":"J. Quant. Spectro. Radiat. Trans."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"16476","DOI":"10.1038\/s41598-022-20624-7","article-title":"Device for automatic measurement of light pollution of the night sky","volume":"12","author":"Kunz","year":"2022","journal-title":"Sci. Rep."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"110196","DOI":"10.1016\/j.jenvman.2020.110196","article-title":"A photometric mapping of the night sky brightness of the Maltese islands","volume":"261","author":"Caruana","year":"2020","journal-title":"J. Environ. Manag."},{"key":"ref_35","first-page":"5","article-title":"Vertical variability of night sky brightness in urbanised areas","volume":"42","author":"Kunz","year":"2023","journal-title":"Quaest. Geogr."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Kyba, C.C.M., Ruhtz, T., Fischer, J., and H\u00f6lker, F. (2011). Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems. PLoS ONE, 6.","DOI":"10.1371\/journal.pone.0017307"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3665","DOI":"10.1093\/mnras\/stu1301","article-title":"Quantitative analysis of night skyglow amplification under cloudy conditions","volume":"443","author":"Kocifaj","year":"2014","journal-title":"Mon. Not. R. Astron. Soc."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.jqsrt.2016.01.032","article-title":"The spectral amplification effect of clouds to the night sky radiance in Madrid","volume":"181","author":"Kocifaj","year":"2016","journal-title":"J. Quant. Spectro. Radiat. Trans."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"6741","DOI":"10.1038\/s41598-017-06998-z","article-title":"Imaging and mapping the impact of clouds on skyglow with all-sky photometry","volume":"7","author":"Jechow","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1093\/astrogeo\/atx025","article-title":"How bright is moonlight?","volume":"58","author":"Kyba","year":"2017","journal-title":"Astron. Geophys."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/j.jqsrt.2019.06.024","article-title":"Night sky photometry over Warsaw (Poland) evaluated simultaneously with surface-based and satellite-based cloud observations","volume":"235","author":"Kotarba","year":"2019","journal-title":"J. Quant. Spectro. Radiat. Trans."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2463","DOI":"10.1093\/mnras\/staa416","article-title":"Sky Quality Meter and satellite correlation for night cloud-cover analysis at astronomical sites","volume":"493","author":"Cavazzani","year":"2020","journal-title":"Mon. Not. R. Astron. Soc."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2622","DOI":"10.1093\/mnras\/stz3514","article-title":"Circalunar variations of the night sky brightness\u2014An FFT perspective on the impact of light pollution","volume":"492","author":"Puschnig","year":"2020","journal-title":"Mon. Not. R. Astron. Soc."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"106962","DOI":"10.1016\/j.jqsrt.2020.106962","article-title":"The impact of clouds on the brightness of the night sky","volume":"247","author":"Sciezor","year":"2020","journal-title":"J. Quant. Spectrosc. Radiat. Transf."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Marseille, C., Aub\u00e9, M., Barreto, A., and Simoneau, A. (2021). Remote sensing of aerosols at night with the CoSQM sky brightness data. Remote Sens., 13.","DOI":"10.20944\/preprints202108.0181.v1"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4449","DOI":"10.1093\/mnras\/stac3003","article-title":"Long-term trends of light pollution assessed from SQM measurements and an empirical atmospheric model(dagger)","volume":"518","author":"Puschnig","year":"2023","journal-title":"Mon. Not. R. Astron. Soc."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1016\/j.jqsrt.2013.12.011","article-title":"The night sky brightness at Potsdam-Babelsberg including overcast and moonlit conditions","volume":"139","author":"Puschnig","year":"2014","journal-title":"J. Quant. Spectrosc. Radiat. Transf."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"5807","DOI":"10.1364\/OPEX.13.005807","article-title":"Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera","volume":"13","author":"Shaw","year":"2005","journal-title":"Opt. Express."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"2000","DOI":"10.1109\/TGRS.2005.853716","article-title":"Cloud statistics measured with the infrared cloud imager","volume":"43","author":"Thurairajah","year":"2005","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"D034772","DOI":"10.1029\/2021JD034772","article-title":"Observations of nighttime clouds over Chiba, Japan, using digital cameras and satellite images","volume":"126","author":"Lagrosas","year":"2021","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Wang, Y., Liu, D., Xie, W., Yang, M., Gao, Z., Ling, X., Huang, Y., Li, C., Liu, Y., and Xia, Y. (2021). Day and night clouds detection using a thermal-infrared all-sky-view camera. Remote Sens., 13.","DOI":"10.3390\/rs13091852"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"D03207","DOI":"10.1029\/2004JD005390","article-title":"Cloud base temperature measurements using a simple longwave infrared cloud detection system","volume":"110","author":"Riordan","year":"2005","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1109\/TGRS.2010.2063033","article-title":"Detection of cirrus clouds using infrared radiometry","volume":"49","author":"Brocard","year":"2011","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_54","first-page":"D19","article-title":"Modification of the IR sky temperature under different atmospheric conditions in an arid region in central Saudi Arabia: Experimental and theoretical justification","volume":"17","author":"Maghrabi","year":"2012","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_55","first-page":"D05201","article-title":"Automatic cloud amount detection by surface longwave downward radiation measurements","volume":"109","author":"Philipona","year":"2004","journal-title":"J. Geophys. Res."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"106657","DOI":"10.1016\/j.atmosres.2023.106657","article-title":"Assessment of cloudless-to-cloud transition zone from downwelling longwave irradiance measurements","volume":"285","author":"Sola","year":"2023","journal-title":"Atmos. Res."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1086\/702250","article-title":"Nighttime ecology: The \u201cNocturnal Problem\u201d revisited","volume":"193","author":"Gaston","year":"2019","journal-title":"Am. Nat."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"108563","DOI":"10.1016\/j.jqsrt.2023.108563","article-title":"Effect of cloud micro-physics on zenith brightness in urban environment","volume":"302","author":"Necas","year":"2023","journal-title":"J. Quant. Spectrosc. Radiat. Transf."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"1557","DOI":"10.1175\/JTECH-D-15-0258.1","article-title":"Error characteristics of ceilometer-based observations of cloud amount","volume":"33","author":"Wagner","year":"2016","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_60","unstructured":"Thomas, W. (2017, January 6\u201310). European ceilometer and lidar networks for aerosol profiling and aviation safety\u2014The German contribution. Proceedings of the 2017 WMO Aeronautical Meteorology Scientific Conference, Toulouse, France. Available online: https:\/\/library.wmo.int\/doc_num.php?explnum_id=4444."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"883","DOI":"10.1175\/BAMS-88-6-883","article-title":"Cloudnet: Continuous evaluation of cloud profiles in seven operational models using groundbased observations","volume":"88","author":"Illingworth","year":"2007","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1175\/2009JTECHA1326.1","article-title":"Detection of cloud-base height using Jenoptik CHM15K and Vaisala CL31 ceilometers","volume":"27","author":"Martucci","year":"2010","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"6013","DOI":"10.5194\/amt-11-6013-2018","article-title":"A multiwavelength numerical model in support of quantitative retrievals of aerosol properties from automated lidar ceilometers and test applications for AOT and PM10 estimation","volume":"11","author":"Dionisi","year":"2018","journal-title":"Atmos. Meas. Tech."},{"key":"ref_64","doi-asserted-by":"crossref","unstructured":"P\u00eerloag\u0103, R., Ene, D., Boldeanu, M., Antonescu, B., O\u2019Connor, E.J., and \u015etefan, S. (2022). Ground-based measurements of cloud properties at the Bucharest\u2013M\u0103gurele Cloudnet Station: First results. Atmosphere, 13.","DOI":"10.3390\/atmos13091445"},{"key":"ref_65","unstructured":"Griffin, C. (1975). Rank Correlation Methods, Oxford University Press. [4th ed.]."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/12\/3063\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:52:54Z","timestamp":1760125974000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/12\/3063"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,6,12]]},"references-count":65,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2023,6]]}},"alternative-id":["rs15123063"],"URL":"https:\/\/doi.org\/10.3390\/rs15123063","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2023,6,12]]}}}