{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,31]],"date-time":"2025-12-31T18:22:29Z","timestamp":1767205349367,"version":"build-2238731810"},"reference-count":12,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T00:00:00Z","timestamp":1662508800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000104","name":"National Aeronautics and Space Administration Ocean Biology and Biogeochemistry","doi-asserted-by":"publisher","award":["80NSSC19K0001"],"award-info":[{"award-number":["80NSSC19K0001"]}],"id":[{"id":"10.13039\/100000104","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Sensors"],"abstract":"<jats:p>Measurements of daytime radiometry in the ocean are necessary to constrain processes such as photosynthesis, photo-chemistry and radiative heating. Profiles of downwelling irradiance provide a means to compute the concentration of a variety of in-water constituents. However, radiometers record a non-negligible signal when no light is available, and this signal is temperature dependent (called the dark current). Here, we devise and evaluate two consistent methods for correction of BGC-Argo radiometry measurements for dark current: one based on measurements during the day, the other based on night measurements. A daytime data correction is needed because some floats never measure at night. The corrections are based on modeling the temperature of the radiometer and show an average bias in the measured value of nearly 0.01 W m\u22122 nm\u22121, 3 orders of magnitude larger than the reported uncertainty of 2.5\u00d710\u22125 W m\u22122 nm\u22121 for the sensors deployed on BGC-Argo floats (SeaBird scientific OCR504 radiometers). The methods are designed to be simple and robust, requiring pressure, temperature and irradiance data. The correction based on nighttime profiles is recommended as the primary method as it captures dark measurements with the largest dynamic range of temperature. Surprisingly, more than 28% of daytime profiles (130,674 in total) were found to record significant downwelling irradiance at 240\u2013250 dbar. The correction is shown to be small relative to near-surface radiance and thus most useful for studies investigating light fields in the twilight zone and the impacts of radiance on deep organisms. Based on these findings, we recommend that BGC-Argo floats profile occasionally at night and to depths greater than 250 dbar. We provide codes to perform the dark corrections.<\/jats:p>","DOI":"10.3390\/s22186771","type":"journal-article","created":{"date-parts":[[2022,9,8]],"date-time":"2022-09-08T04:18:32Z","timestamp":1662610712000},"page":"6771","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Correction of Radiometry Data for Temperature Effect on Dark Current, with Application to Radiometers on Profiling Floats"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2618-814X","authenticated-orcid":false,"given":"Terence","family":"O\u2019Brien","sequence":"first","affiliation":[{"name":"Institute for the study of Earth, Ocean and Space, University of New Hampshire, Durham, NH 03824, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8334-9595","authenticated-orcid":false,"given":"Emmanuel","family":"Boss","sequence":"additional","affiliation":[{"name":"School of Marine Sciences, University of Maine, Orono, ME 04469, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"C06020","DOI":"10.1029\/2010JC006899","article-title":"Combined processing and mutual interpretation of radiometry and fluorimetry from autonomous profiling Bio-Argo floats: Chlorophyll a retrieval","volume":"116","author":"Xing","year":"2011","journal-title":"J. Geophys. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"C04022","DOI":"10.1029\/2011JC007632","article-title":"Combined processing and mutual interpretation of radiometry and fluorometry from autonomous profiling Bio-Argo floats: 2. Colored dissolved organic matter absorption retrieval: CDOM absorption retrieval from Bio-Argo","volume":"117","author":"Xing","year":"2012","journal-title":"J. Geophys. Res. Ocean."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"439","DOI":"10.3389\/fmars.2019.00439","article-title":"On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array","volume":"6","author":"Roemmich","year":"2019","journal-title":"Front. Mar. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Xing, X., and Lagunas-Morales, J. (2018). Laboratory results on the dependence of dark current upon environmental temperature variability for Satlantic\u2019s OCR504 radiometers. Optical Precision Manufacturing, Testing, and Applications, Proc. SPIE 10847.","DOI":"10.1117\/12.2504241"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Jutard, Q., Organelli, E., Briggs, N., Xing, X., Schmechtig, C., Boss, E., Poteau, A., Leymarie, E., Cornec, M., and D\u2019Ortenzio, F. (2021). Correction of Biogeochemical-Argo Radiometry for Sensor Temperature-Dependence and Drift: Protocols for a Delayed-Mode Quality Control. Sensors, 21.","DOI":"10.3390\/s21186217"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1002\/lob.200312229","article-title":"The Blank Can Make a Big Difference in Oceanographic Measurements","volume":"12","author":"Cullen","year":"2003","journal-title":"Limnol. Oceanogr. Bull."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3543","DOI":"10.1002\/2016JC012629","article-title":"Bio-optical anomalies in the world\u2019s oceans: An investigation on the diffuse attenuation coefficients for downward irradiance derived from Biogeochemical Argo float measurements: World\u2019s ocean bio-optical anomalies","volume":"122","author":"Organelli","year":"2017","journal-title":"J. Geophys. Res. Ocean."},{"key":"ref_8","unstructured":"Koblick, D. (2021, July 26). Vectorized Solar Azimuth and Elevation Estimation. MATLAB Central File Exchange. Available online: https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/23051-vectorized-solar-azimuth-and-elevation-estimation."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"502","DOI":"10.3389\/fmars.2019.00502","article-title":"A BGC-Argo Guide: Planning, Deployment, Data Handling and Usage","volume":"6","author":"Bittig","year":"2019","journal-title":"Front. Mar. 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USA"}],"updated-by":[{"DOI":"10.3390\/s23125700","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2022,9,7]],"date-time":"2022-09-07T00:00:00Z","timestamp":1662508800000}}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/18\/6771\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,3]],"date-time":"2025-08-03T13:48:02Z","timestamp":1754228882000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/18\/6771"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,7]]},"references-count":12,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2022,9]]}},"alternative-id":["s22186771"],"URL":"https:\/\/doi.org\/10.3390\/s22186771","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,9,7]]}}}