ESSDD Earth System Science Data Discussions ESSDD Earth Syst. Sci. Data Discuss. 1866-3591 Göttingen, Germany 10.5194/essd-2026-539 A compilation of global bio-optical <em>in situ</em> data for ocean-colour satellite applications &ndash; version four Salem Salem Ibrahim 1 2 Valente Andre 3 4 Sathyendranath Shubha 1 5 Chuprin Andrei 1 Renard Théo 6 Pitarch Jaime https://orcid.org/0000-0003-0239-0033 7 Airs Ruth 1 Ana Moreno 8 Angelico Maria-Manuel 8 Antoine David https://orcid.org/0000-0002-9082-2395 9 10 Arnone Robert 11 Artuso Florinda 12 Oliveira Paulo O. https://orcid.org/0000-0001-6838-7377 8 Balch William 13 Barker Kathryn 14 Barlow Ray 15 Bélanger Simon 16 Bellacicco Marco 7 Berthon Jean-François 17 Beşiktepe Şükrü https://orcid.org/0000-0002-9615-4746 18 Bignami Francesco 7 Borsheim Yngve 19 Bracher Astrid https://orcid.org/0000-0003-3025-5517 20 21 Braga Federica 7 Brando Vittorio https://orcid.org/0000-0002-2193-5695 7 Brewin Robert J. W. 22 Brotas Vanda https://orcid.org/0000-0001-8612-4167 4 1 Canuti Elisabetta 17 Chavez Francisco P. https://orcid.org/0000-0002-0691-292X 23 Cianca Andrés https://orcid.org/0000-0003-2108-0540 24 Claustre Hervé https://orcid.org/0000-0001-6243-0258 10 Clementson Lesley https://orcid.org/0000-0003-4415-993X 14 Colella Simone https://orcid.org/0000-0002-7727-7353 7 Costa Raul https://orcid.org/0000-0002-0940-3565 25 26 Nunes Cristina 8 Crout Richard 27 Devred Emmanuel https://orcid.org/0000-0001-9446-0005 29 Di Cicco Annalisa 7 Falcini Federico 7 Farace Ivan https://orcid.org/0009-0006-9869-905X 7 Ferreira Afonso 3 28 Freeman Scott 30 Frouin Robert 31 García-Soto Carlos 32 33 Giardina Isabella 12 Gibb Stuart W. 34 Gleason Arthur 35 Goericke Ralf 31 Gould Richard 27 Grant Michael 1 36 Guillocheau Nathalie 37 Higa Hiroto 38 Hooker Stanford B. 30 Hu Chuamin https://orcid.org/0000-0003-3949-6560 39 Ishizaka Joji https://orcid.org/0000-0003-0398-1572 40 Jackson Thomas 36 1 Kahru Mati 31 Kampel Milton 41 Kim Bokyung 42 Klein Holger 43 Kowalczuk Piotr https://orcid.org/0000-0001-6016-0610 44 Kratzer Susanne 45 Kudela Raphael https://orcid.org/0000-0002-8640-1205 46 Lai Antonia 12 Lavezza Rosario 19 Ledesma Jesus 47 Lee Huiwon 48 Lohrenz Steven https://orcid.org/0000-0003-3811-2975 49 Loisel Hubert 50 Lutz Vivian 51 Mannino Antonio 30 Margiotta Francesca 52 Martinez-Vicente Victor https://orcid.org/0000-0003-3492-583X 1 Marullo Salvatore 7 Massi Luca 53 Matrai Patricia https://orcid.org/0000-0003-1656-5519 13 Matsuoka Atsushi 54 McKee David 55 Melillo Chiara 53 Mendes Carlos B. 28 25 Mitchell Brian G. https://orcid.org/0000-0002-8550-4333 31 Moisan Tiffany 56 74 Montes Enrique 57 58 Muller-Karger Frank https://orcid.org/0000-0003-3159-5011 39 Neeley Aimee 30 Novak Michael 30 O'Dowd Leonie 59 Ondrusek Michael 60 Organelli Emanuele https://orcid.org/0000-0001-8191-8179 7 Park Heeyoon 61 Platt Trevor 1 74 Polonelli Francesca 53 Poulton Alex https://orcid.org/0000-0002-5149-6961 62 Ragni Mariella 52 Repecaud Michel 63 Ribera d’Alcalà Maurizio 52 Rodriguez-Ramos Tamara 64 Röttgers Rüdiger 65 Ruiz-Villarreal Manuel https://orcid.org/0000-0003-0169-0958 64 Sammartino Michela 66 Santoleri Rosalia https://orcid.org/0000-0002-2900-5054 7 Scarpa Gian Marco https://orcid.org/0000-0002-5061-5607 7 Schroeder Thomas 14 Segura Valeria 51 Smyth Timothy https://orcid.org/0000-0003-0659-1422 1 Smythe-Wright Denise 67 Sosik Heidi M. https://orcid.org/0000-0002-4591-2842 68 Stoń-Egiert Joanna https://orcid.org/0000-0002-4274-8979 44 Taberner Malcolm 36 Tan Jing https://orcid.org/0000-0001-9021-6873 31 Thomas Rob 59 Thomas Crystal 30 Tilstone Gavin 1 Tracana Andreia 3 Twardowski Michael 69 Vellucci Vincenzo https://orcid.org/0000-0001-5392-7457 10 Volpe Gianluca 7 Voss Kenneth 35 Werdell Jeremy 30 Wernand Marcel 70 74 Wojtasiewicz Bozena https://orcid.org/0000-0002-2878-2134 71 Wright Simon 72 Yang Sunmi 48 Zibordi Giuseppe https://orcid.org/0000-0002-2253-1828 17 Zoffoli Maria Laura 73 Groom Steve 1 Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, United Kingdom Faculty of Engineering, Alexandria University, Al Horreya Avenue, Alexandria 11432, Egypt Atlantic International Research Centre (AIR Centre), Caminho do Lameirinho, Angra do Heroísmo 9700-117, Portugal MARE - Marine and Environmental Sciences Centre/ARNET - Aquatic Research Network, Faculdade de Ciências, Universidade de Lisboa, Campo Grande 016, 1749-016 Lisboa, Portugal National Centre for Earth Observation, Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, United Kingdom Faculty of Sciences, University of Liège, Allée du Six Août 11, Liège 4000, Belgium Institute of Marine Sciences, National Research Council of Italy (CNR-ISMAR), Via del Fosso del Cavaliere 100, Rome 00133, Italy Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, Lisboa 1749-077, Portugal Remote Sensing and Satellite Research Group, School of Earth and Planetary Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia Sorbonne Université, CNRS, Institut de la Mer de Villefranche, 181 Chemin du Lazaret, Villefranche-sur-Mer 06230, France School of Ocean Science and Engineering, The University of Southern Mississippi, 1020 Balch Boulevard, Stennis Space Center, MS 39529, United States of America Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Via Enrico Fermi 45, Frascati (Rome) 00044, Italy Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, ME 04544, United States of America The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Bayworld Centre for Research and Education, Beach Road, Gqeberha 6013, South Africa Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC G5L 3A1, Canada European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra 21027, Italy Institute of Marine Sciences and Technology, Dokuz Eylül University, Baku Bulvarı No. 100, İzmir 35340, Türkiye Institute of Marine Research, Nordnesgaten 50, Bergen 5005, Norway Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven 27570, Germany Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany Centre for Geography and Environmental Science, University of Exeter, Treliever Road, Penryn TR10 9FE, United Kingdom Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039, United States of America Oceanic Platform of the Canary Islands (PLOCAN), Carretera de Taliarte s/n, Telde 35214, Spain Federal University of Rio Grande (FURG), Avenida Itália, km 8, Rio Grande 96203-900, Brazil National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom U.S. Naval Research Laboratory, 1005 Balch Boulevard, Stennis Space Center, MS 39529, United States of America Departamento de Biologia, Faculdade de Ciências, Universidade de Lisboa, Campo Grande 016, 1749-016 Lisboa, Portugal Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, NS B2Y 4A2, Canada National Aeronautics and Space Administration, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, United States of America Scripps Institution of Oceanography, University of California San Diego, 8622 Kennel Way, La Jolla, CA 92037, United States of America Spanish Institute of Oceanography, Spanish National Research Council (IEO-CSIC), Corazón de María 8, Madrid 28002, Spain Plentzia Marine Station, University of the Basque Country (PIE-UPV/EHU), Areatza Pasealekua s/n, Plentzia 48620, Spain Environmental Research Institute, University of the Highlands and Islands, Castle Street, Thurso KW14 7JD, United Kingdom Department of Physics, University of Miami, 1320 Campo Sano Avenue, Coral Gables, FL 33146, United States of America European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), Eumetsat-Allee 1, Darmstadt 64295, Germany Earth Research Institute, University of California Santa Barbara, 6832 Ellison Hall, Santa Barbara, CA 93106-3060, United States of America Faculty of Urban Innovation, Yokohama National University, 79-1 Tokiwadai, Yokohama 240-8501, Japan College of Marine Science, University of South Florida, 140 Seventh Avenue South, St. Petersburg, FL 33701, United States of America Institute for Space–Earth Environmental Research, Nagoya University, Furo-cho, Nagoya 464-8601, Japan National Institute for Space Research (INPE), Avenida dos Astronautas 1758, São José dos Campos 12227-010, Brazil Division of Exhibition and Education, Cheongju National Ocean Science Museum, 52 Millenieom 1-ro, Cheongju-si 28353, Republic of Korea Federal Maritime and Hydrographic Agency, Bernhard-Nocht-Straße 78, Hamburg 20359, Germany Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, Sopot 81-712, Poland Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States of America Instituto del Mar del Perú, Esquina Gamarra y General Valle s/n, Callao 07021, Peru Marine Convergence Department, Underwater Survey Technology 21 Co., Ltd., 12 Gaetbeol-ro, Incheon 21999, Republic of Korea University of Massachusetts Dartmouth, 285 Old Westport Road, Dartmouth, MA 02747, United States of America Université du Littoral Côte d’Opale, Université de Lille, CNRS, 32 Avenue Foch, Wimereux 62930, France Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Paseo Victoria Ocampo 1, Mar del Plata B7602HSA, Argentina Stazione Zoologica Anton Dohrn, Villa Comunale, Naples 80121, Italy University of Florence, Via Micheli 1, Florence 50121, Italy Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Road, Durham, NH 03824, United States of America University of Strathclyde, 16 Richmond Street, Glasgow G1 1XQ, United Kingdom National Aeronautics and Space Administration, Goddard Space Flight Center, Wallops Flight Facility, Wallops Island, VA 23337, United States of America Cooperative Institute for Marine and Atmospheric Studies, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, United States of America National Oceanic and Atmospheric Administration, Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Causeway, Miami, FL 33149, United States of America Marine Institute, Rinville, Oranmore H91 R673, Ireland National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service, Center for Satellite Applications and Research, 5830 University Research Court, College Park, MD 20740, United States of America National Ocean Satellite Center, Korea Hydrographic and Oceanographic Agency, 351 Haeyang-ro, Busan 49111, Republic of Korea Heriot-Watt University, Boundary Road, Edinburgh EH14 4AS, United Kingdom French Research Institute for Exploitation of the Sea (IFREMER), Centre de Brest, 1625 Route de Sainte-Anne, Plouzané 29280, France Spanish Institute of Oceanography, Spanish National Research Council (IEO-CSIC), Paseo Marítimo Alcalde Francisco Vázquez 10, A Coruña 15001, Spain Helmholtz-Zentrum Hereon, Max-Planck-Straße 1, Geesthacht 21502, Germany Institute of Marine Sciences, National Research Council of Italy (CNR-ISMAR), Calata Porta di Massa, Naples 80133, Italy National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543-1050, United States of America Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US Highway 1 North, Fort Pierce, FL 34946, United States of America Royal Netherlands Institute for Sea Research (NIOZ), Landsdiep 4, ’t Horntje 1797 SZ, The Netherlands Australian Institute of Marine Science, Indian Ocean Marine Research Centre, Crawley, WA 6009, Australia Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, TAS 7004, Australia Institute of Marine Sciences, National Research Council of Italy (CNR-ISMAR), Area Science Park Basovizza - Edificio Q2 - Strada Statale 14, km 163.5, Trieste 34149, Italy deceased 21 08 2026 2026 1 99 Copyright: © 2026 Salem Ibrahim Salem et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://essd.copernicus.org/preprints/essd-2026-539/ The full text article is available as a PDF file from https://essd.copernicus.org/preprints/essd-2026-539/essd-2026-539.pdf

A global <em>in situ</em> dataset for validation of satellite products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, with data starting in 1996, extends to 2025, which is important for the validation of recent algorithms and satellite products. The dataset comprises <em>in situ</em> observations of the following variables: spectral remote-sensing reflectance (rrs), chlorophyll-a concentration ("chla"; HPLC and fluorometric), spectral inherent optical properties (IOPs: algal pigment absorption "aph", detritus plus gelbstoff absorption "adg", and particle backscattering "bbp"), spectral diffuse attenuation coefficient (kd) and total suspended matter (tsm). Data were obtained from multiple archives acquired via open internet services, or from individual projects, acquired directly from data providers. Compared to the previous version (Valente et al., 2022) this release incorporates updates from existing sources and introduces data from 13 additional sources. Notably, AERONET-OC coverage has been significantly expanded (39 sites compared to 11 in v2022) and MOBY Platinum data have been included from 2024. Methodologies were implemented for homogenisation, quality control and merging of all data. Minimal changes were made to the original data, other than conversion to a standard format, elimination of some points after quality control and averaging of observations that were close in time and space. The harmonisation procedures also include the application of a bidirectional reflectance distribution function (BRDF) correction to "rrs". The result is a merged table available in text format. Overall, the dataset increased by ~115 %, reaching 319,183 rows, with each row representing a unique station in space and time (cf 148,432 rows in Valente et al., 2022). Records of chlaovera increased by ~31 % (82,543 to 107,922); "rrs" observations nearly doubled +94 % (68,641 &rarr; 133,325); IOPs showed substantial expansion, with aph increasing by ~150 % (4,265 to 10,655) and adg by 78 % (1,654 to 2,948). The most pronounced change was for bbp, which increased by ~10,258 % (792 to 82,033), while moderate increases were observed for kd (+30 %; 2,454 to 3,197) and "tsm" (+51 %; 1,546 to 2,334). Metadata of each <em>in situ</em> measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented, and it is also possible to analyse each set of data separately. The compiled data are available at (Salem et al., 2026).