{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T02:16:45Z","timestamp":1777515405469,"version":"3.51.4"},"reference-count":68,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,2,28]],"date-time":"2020-02-28T00:00:00Z","timestamp":1582848000000},"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>The Alqueva reservoir (South of Portugal) in the Guadiana river basin constitutes the most important water resource in southern Portugal for domestic and agricultural consumption. We present a methodology developed to characterize spatial and temporal variations of Secchi depth and diffuse attenuation coefficient (both related to dissolved\/suspended particles and to water transparency), using high spatial resolution satellite images from Sentinel-2 Multi-Spectral Instrument (MSI). Empirical relations between satellite retrievals of surface reflectances and in situ measurements of water parameters were defined and applied to the entire reservoir for spatial and temporal analysis in the period July 2017\u2013June 2019, useful in the identification of microalgae blooms and rapid variations in water characteristics, which allowed us to differentiate five zones. Water estimates with lower transparency and higher attenuation of radiation were found in the northern area of Alqueva reservoir during the months characterized by higher water temperatures, with Secchi depth monthly averages near 1.0 m and diffuse attenuation coefficient near or above 1.5 m-1. Satellite retrievals of water with greater transparency in the reservoir were obtained in the southern area in months with low water temperature and atmospheric stability, presenting some monthly Secchi depth averages above 3 m, and diffuse attenuation coefficient below 0.8 m-1. January 2018 presented great transparency of water with a Secchi depth of 7.5 m for pixels representing the 95th percentile and diffuse attenuation coefficient of 0.36 m for pixels representing the 5th percentile in the Southern region.<\/jats:p>","DOI":"10.3390\/rs12050768","type":"journal-article","created":{"date-parts":[[2020,3,3]],"date-time":"2020-03-03T03:13:28Z","timestamp":1583205208000},"page":"768","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["Temporal and Spatial Variations of Secchi Depth and Diffuse Attenuation Coefficient from Sentinel-2 MSI over a Large Reservoir"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2273-7647","authenticated-orcid":false,"given":"Gon\u00e7alo","family":"Rodrigues","sequence":"first","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8912-5277","authenticated-orcid":false,"given":"Miguel","family":"Potes","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2981-2232","authenticated-orcid":false,"given":"Maria Jo\u00e3o","family":"Costa","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"},{"name":"Department of Physics, School of Science and Technology, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0870-2221","authenticated-orcid":false,"given":"Maria Helena","family":"Novais","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"},{"name":"Water Laboratory, University of \u00c9vora, P.I.T.E. Rua da Barba Rala No. 1, 7005-345 \u00c9vora, Portugal"},{"name":"Renewable Energies Chair, University of \u00c9vora, Casa Cordovil, Rua D. Augusto Eduardo Nunes, n.7, 7000-651 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6803-3202","authenticated-orcid":false,"given":"Alexandra March\u00e3","family":"Penha","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"},{"name":"Water Laboratory, University of \u00c9vora, P.I.T.E. Rua da Barba Rala No. 1, 7005-345 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1311-6291","authenticated-orcid":false,"given":"Rui","family":"Salgado","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"},{"name":"Department of Physics, School of Science and Technology, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0482-4309","authenticated-orcid":false,"given":"Maria Manuela","family":"Morais","sequence":"additional","affiliation":[{"name":"Institute of Earth Sciences, Institute for Advanced Studies and Research, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"},{"name":"Water Laboratory, University of \u00c9vora, P.I.T.E. Rua da Barba Rala No. 1, 7005-345 \u00c9vora, Portugal"},{"name":"Department of Biology, School of Science and Technology, University of \u00c9vora, 7000-671 \u00c9vora, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1038\/nclimate1452","article-title":"A decade of weather extremes","volume":"2","author":"Coumou","year":"2012","journal-title":"Nature Clim. Chang."},{"key":"ref_2","unstructured":"Meehl, G., Stocker, T., Collins, W., Friedlingstein, P., Gaye, A., Gregory, J., Kitoh, A., Knutti, R., Murphy, J., and Noda, A. (2007). Global Climate Projections, Climate Change 2007: The Physical Science Basis, Cambridge University Press."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"512","DOI":"10.1038\/415512a","article-title":"Quantifying the risk of extreme seasonal precipitation events in a changing climate","volume":"415","author":"Palmer","year":"2002","journal-title":"Nature"},{"key":"ref_4","unstructured":"Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P.M. (2013). Climate change 2013: The physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental. Panel on Climate Change, Cambridge University Press."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"522","DOI":"10.1002\/2014RG000464","article-title":"Future changes to the intensity and frequency of short-duration extreme rainfall","volume":"52","author":"Westra","year":"2014","journal-title":"Rev. Geophys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1007\/s00382-018-4124-4","article-title":"Mean and extreme temperatures in a warming climate: EURO CORDEX and WRF regional climate high-resolution projections for Portugal","volume":"52","author":"Cardoso","year":"2018","journal-title":"Clim. Dyn."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2503","DOI":"10.1007\/s00382-016-3455-2","article-title":"Future precipitation in Portugal: High-resolution projections using WRF model and EURO-CORDEX multi-model ensembles","volume":"49","author":"Soares","year":"2017","journal-title":"Clim Dyn"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Havens, K., and Jeppesen, E. (2018). Ecological Responses of Lakes to Climate Change. Water, 10.","DOI":"10.3390\/w10070917"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1007\/s10750-014-2169-x","article-title":"Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and salinity","volume":"750","author":"Jeppesen","year":"2015","journal-title":"Hydrobiologia"},{"key":"ref_10","first-page":"27","article-title":"Climate change: A catalyst for global expansion of harmful blooms","volume":"1","author":"Paerl","year":"2009","journal-title":"Environ. Microbiol"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Duan, W., He, B., Nover, D., Yang, G., Chen, W., Meng, H., Zou, S., and Liu, C. (2016). Water Quality Assessment and Pollution Source Identification of the Eastern Poyang Lake Basin Using Multivariate Statistical Methods. Sustainability, 8.","DOI":"10.3390\/su8020133"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1016\/j.scitotenv.2013.05.022","article-title":"Spatial and temporal trends in estimates of nutrient and suspended sediment loads in the Ishikari River, Japan, 1985 to 2010","volume":"461","author":"Duan","year":"2013","journal-title":"Sci. Total Environ."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"9492","DOI":"10.3390\/ijerph120809492","article-title":"Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin\u2019anjiang Reservoir: Implications for Reservoir Management","volume":"12","author":"Wu","year":"2015","journal-title":"Int. J. Environ. Res. Public Health"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Zou, S., Jilili, A., Duan, W., Maeyer, P.D., and de Voorde, T.V. (2019). Human and Natural Impacts on the Water Resources in the Syr Darya River Basin, Central Asia. Sustainability, 11.","DOI":"10.3390\/su11113084"},{"key":"ref_15","first-page":"31","article-title":"Assessing changes in drought and wetness episodes in drainage basins using the Standardized Precipitation Index","volume":"65","author":"Silva","year":"2014","journal-title":"Bodenkultur"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1007\/BF02804901","article-title":"Harmful algal blooms and eutrophication: Nutrient sources, composition, and consequences","volume":"25","author":"Donald","year":"2002","journal-title":"Estuar. Coasts"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"101","DOI":"10.5268\/IW-1.2.359","article-title":"Allied attack: Climate change and eutrophication","volume":"1","author":"Moss","year":"2011","journal-title":"Inland Waters"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.rse.2014.09.021","article-title":"Remote sensing of inland waters: Challenges, progress and future directions","volume":"157","author":"Palmer","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3987","DOI":"10.1080\/01431160802575653","article-title":"Land Surface Water Index (LSWI) response to rainfall and NDVI using the MODIS Vegetation Index product","volume":"31","author":"Chandrasekar","year":"2010","journal-title":"Int. J. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Barrett, D., and Frazier, A. (2016). Automated Method for Monitoring Water Quality Using Landsat Imagery. Water, 8.","DOI":"10.3390\/w8060257"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"3373","DOI":"10.1080\/01431161003747513","article-title":"Remote sensing of water quality parameters over Alqueva reservoir in the south of Portugal","volume":"32","author":"Potes","year":"2011","journal-title":"Int. J. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1623","DOI":"10.5194\/hess-16-1623-2012","article-title":"Satellite remote sensing of water turbidity in Alqueva reservoir and implications on lake modeling","volume":"16","author":"Potes","year":"2012","journal-title":"Hydrol. Earth Syst. Sci."},{"key":"ref_23","first-page":"73","article-title":"Use of Sentinel 2-MSI for water quality monitoring at Alqueva reservoir, Portugal","volume":"380","author":"Potes","year":"2018","journal-title":"Proc. Int. Assoc. Hydrol. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"4086","DOI":"10.1016\/j.rse.2007.12.013","article-title":"A 20-year Landsat water clarity census of Minnesota\u2019s 10,000 lakes","volume":"112","author":"Olmanson","year":"2008","journal-title":"Remote Sens. Environ."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1016\/j.rse.2012.04.004","article-title":"The Possibility of Using the Landsat Image Archive for Monitoring Long Trend in Colored Dissolved Organic Matter Concentration in Lake Waters","volume":"123","author":"Kuster","year":"2012","journal-title":"Remote Sens. Environ."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Liu, H., Li, Q., Shi, T., Hu, S., Wu, G., and Zhou, Q. (2017). Application of Sentinel 2 MSI Images to Retrieve Suspended Particulate Matter Concentrations in Poyang Lake. Remote Sens., 9.","DOI":"10.3390\/rs9070761"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Toming, K., Kutser, T., Laas, A., Sepp, M., Paavel, B., and N\u00f5ges, T. (2016). First experiences in mapping lake water quality parameters with Sentinel-2 MSI imagery. Remote Sens., 8.","DOI":"10.3390\/rs8080640"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.rse.2017.08.033","article-title":"Sentinel-2 MultiSpectral Instrument (MSI) data processing for aquatic science applications: Demonstrations and validations","volume":"201","author":"Pahlevan","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Ansper, A., and Alikas, K. (2019). Retrieval of Chlorophyll a from Sentinel-2 MSI Data for the European Union Water Framework Directive Reporting Purposes. Remote Sens., 11.","DOI":"10.3390\/rs11010064"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Molkov, A.A., Fedorov, S.V., Pelevin, V.V., and Korchemkina, E.N. (2019). Regional Models for High-Resolution Retrieval of Chlorophyll a and TSM Concentrations in the Gorky Reservoir by Sentinel-2 Imagery. Remote Sens., 11.","DOI":"10.3390\/rs11101215"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Soomets, T., Uudeberg, K., Jakovels, D., Brauns, A., Zagars, M., and Kutser, T. (2020). Validation and Comparison of Water Quality Products in Baltic Lakes Using Sentinel-2 MSI and Sentinel-3 OLCI Data. Sensors, 20.","DOI":"10.3390\/s20030742"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Martins, V.S., Barbosa, C.C.F., De Carvalho, L.A.S., Jorge, D.S.F., Lobo, F.D.L., and Novo, E.M.L.M. (2017). Assessment of Atmospheric Correction Methods for Sentinel-2 MSI Images Applied to Amazon Floodplain Lakes. Remote Sens., 9.","DOI":"10.3390\/rs9040322"},{"key":"ref_33","unstructured":"Richter, R., Louis, J., and M\u00fcller-Wilm, U. (2012). Sentinel-2 MSI\u2014Level 2A Products Algorithm Theoretical Basis Document, Telespazio VEGA Deutschland GmbH. S2PAD-ATBD-0001, Issue 2.0."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Markert, K.N., Schmidt, C.M., Griffin, R.E., Flores, A.I., Poortinga, A., Saah, D.S., Muench, R.E., Clinton, N.E., Chishtie, F., and Kityuttachai, K. (2018). Historical and operational monitoring of surface sediments in the lower mekong basin using landsat and Google earth engine cloud computing. Remote Sens., 10.","DOI":"10.3390\/rs10060909"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Shang, P., and Shen, F. (2016). Atmospheric correction of satellite GF-1\/WFV imagery and quantitative estimation of suspended particulate matter in the yangtze estuary. Sensors, 16.","DOI":"10.3390\/s16121997"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Wang, D., Ma, R., Xue, K., and Loiselle, S.A. (2019). The assessment of Landsat-8 OLI atmospheric correction algorithms for inland waters. Remote Sens., 11.","DOI":"10.3390\/rs11020169"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"7","DOI":"10.3389\/fenvs.2020.00007","article-title":"Hyperspectral Satellite Remote Sensing of Water Quality in Lake Atitl\u00e1n, Guatemala","volume":"8","author":"Griffin","year":"2020","journal-title":"Front. Environ. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Hansen, C.H., Burian, S.J., Dennison, P.E., and Williams, G.P. (2017). Spatiotemporal Variability of Lake Water Quality in the Context of Remote Sensing Models. Remote Sens., 9.","DOI":"10.3390\/rs9050409"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"20774","DOI":"10.3402\/tellusa.v65i0.20774","article-title":"Spectral measurements of underwater downwelling radiance of inland water bodies","volume":"65","author":"Potes","year":"2013","journal-title":"Tellus A"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Kotchenova, S.Y., and Vermote, E.F. (2007, January 13\u201314). A vector version of the 6S radiative transfer code for atmospheric correction of satellitedata: An Overview. Proceedings of the 29th Review of Atmospheric Transmission Models Meeting, Lexington, MA, USA.","DOI":"10.1364\/AO.46.004455"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1109\/36.581987","article-title":"Second Simulation of the Satellite Signal in the Solar Spectrum, 6S: An Overview","volume":"35","author":"Vermote","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"6762","DOI":"10.1364\/AO.45.006762","article-title":"Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part I: Path radiance","volume":"45","author":"Kotchenova","year":"2006","journal-title":"Appl. Opt."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"4455","DOI":"10.1364\/AO.46.004455","article-title":"Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part II: Homogeneous Lambertian and anisotropic surfaces","volume":"46","author":"Kotchenova","year":"2007","journal-title":"Appl. Opt."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Obreg\u00f3n, M.A., Costa, M.J., and Silva, A.M. (2019). Validation of ESA Sentinel-2 L2A Aerosol Optical Thickness and Columnar Water Vapour during 2017\u20132018. Remote Sens., 11.","DOI":"10.3390\/rs11141649"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"ASD (2010). FieldSpec\u00ae HandHeld 2 Spectroradiometer User\u2019s Manual, ASD Inc.","DOI":"10.4016\/11826.01"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1016\/S0034-4257(02)00022-6","article-title":"A procedure for regional lake water clarity assessment using Landsat multispectral data","volume":"82","author":"Kloiber","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4330","DOI":"10.1016\/S0043-1354(02)00146-X","article-title":"Application of Landsat imagery to regional-scale assessments of lake clarity","volume":"36","author":"Kloiber","year":"2002","journal-title":"Water Res."},{"key":"ref_48","first-page":"158","article-title":"Atmospheric correction assessment of SPOT-6 image and its influence on models to estimate water column transparency in tropical reservoir","volume":"4","author":"Rotta","year":"2016","journal-title":"Remote Sens. Appl. Soc. Environ."},{"key":"ref_49","first-page":"343","article-title":"1985. Monitoring water quality conditions in a large western reservoir with Landsat Imagery","volume":"51","author":"Verdin","year":"1985","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1016\/0034-4257(93)90047-2","article-title":"Water quality monitoring in estuarine waters 511 using the Landsat Thematic Mapper","volume":"46","author":"Lavery","year":"1993","journal-title":"Remote Sens. Environ."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2183","DOI":"10.1080\/01431160701422254","article-title":"Comparison of MODIS and 505 Landsat TM5 images for mapping tempo-spatial dynamics of Secchi disk depths in Poyang Lake 506 National Nature Reserve, China","volume":"29","author":"Wu","year":"2008","journal-title":"Int. J. Remote Sens."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"2345","DOI":"10.1016\/j.asr.2015.09.018","article-title":"Effects of atmospheric correction of Landsat imagery on lake water clarity assessment","volume":"56","author":"Bonansea","year":"2015","journal-title":"Adv. Space Res."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Delegido, J., Urrego, E.P., Vicente, E., Perpiny\u00e0, X.S., Soria, J.M., Sandoval, M.P., Ruiz-Verd\u00fa, A., Pe\u00f1a, R., and Moreno, J. (2019). Turbidez y profundidad de disco de Secchi con Sentinel-2 en embalses con diferente estado tr\u00f3fico en la Comunidad Valenciana. Revista de Teledetecci\u00f3n, 15\u201324.","DOI":"10.4995\/raet.2019.12603"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"111284","DOI":"10.1016\/j.rse.2019.111284","article-title":"A harmonized image processing workflow using Sentinel-2\/MSI and Landsat-8\/OLI for mapping water clarity in optically variable lake systems","volume":"231","author":"Page","year":"2019","journal-title":"Remote Sens. Environ."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"348","DOI":"10.4319\/lo.1967.12.2.0343","article-title":"Determination of chlorophyll and phaeopigments: Spectrophotometric equations","volume":"12","author":"Lorenzen","year":"1967","journal-title":"Limnol. Oceanogr."},{"key":"ref_56","unstructured":"IPQ (1997). Qualidade da \u00e1gua. Doseamento da clorofila a e dos feopigmentos por espectrofotometria de absor\u00e7\u00e3o molecular. M\u00e9todo de extrac\u00e7\u00e3o com acetona. NP 4327\/1996, Instituto Portugu\u00eas da Qualidade."},{"key":"ref_57","unstructured":"ISO, and EN ISO 10260:1992 (1992). Water Quality\u2014Measurement of Biochemical Parameters\u2014Spectrometric Determination of the Chlorophyll-a Concentration, International Organization for Standardization."},{"key":"ref_58","unstructured":"APHA (1995). Standard Methods for the Examination of Water and Wastewater, American Public Health Association, American Water Works Association, and Water Pollution Control Federation. [19th ed.]."},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Du, Y., Zhang, Y., Ling, F., Wang, Q., Li, W., and Li, X. (2016). Water bodies\u2019 mapping from Sentinel-2 imagery with modified normalized difference water index at 10-m spatial resolution produced by sharpening the SWIR band. Remote Sens., 8.","DOI":"10.3390\/rs8040354"},{"key":"ref_60","first-page":"110","article-title":"Changes in turbidity as a result of mineralization in the lower Vaal River","volume":"9","author":"Grobler","year":"1983","journal-title":"Water SA"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/BF00023982","article-title":"Light, temperature and flow regimes of the Vaal River at Balkfontein, South Africa","volume":"277","author":"Roos","year":"1994","journal-title":"Hydrobiologia"},{"key":"ref_62","unstructured":"Oliver, R.L., Hart, B.T., Olley, J., Grace, M., Rees, C., and Caitcheon, G. (1999). The Darling River: Algal Growth and the Cycling and Sources of Nutrients, CRS for Freshwater Ecology, CSIRO Land and Water. Murray Darling Basin Commission Project M386."},{"key":"ref_63","unstructured":"Giblin, S., Hoff, K., Fischer, J., and Dukerschein, T. (2010). Evaluation of Light Penetration on Navigation Pools 8 and 13 of the Upper Mississippi River. Long Term Resource Monitoring Program, U.S. Geological Survey. Technical Report 2010-T001."},{"key":"ref_64","unstructured":"Gunter, G., and do Carmo Sobral, M. (2007). Monitoring the water quality in Alqueva reservoir, Guadiana River, southern Portugal. Reservoir and River Basin Management: Exchange of Experiences from Brazil Portugal and Germany, Technical University of Berlin."},{"key":"ref_65","doi-asserted-by":"crossref","unstructured":"Novais, M.H., Penha, A., Morales, E., Potes, M., Salgado, R., and Morais, M. (2018). Vertical distribution of benthic diatoms in a large reservoir (Alqueva, Southern Portugal) during thermal stratification. Sci. Total Environ., 659.","DOI":"10.1016\/j.scitotenv.2018.12.251"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1007\/s10661-009-0965-y","article-title":"Assessment of anthropogenic sources of water pollution using multivariate statistical techniques: A case study of the Alqueva\u2019s reservoir, Portugal","volume":"165","author":"Palma","year":"2010","journal-title":"Environ. Monit. Assess."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1007\/s11356-009-0143-3","article-title":"Evaluation of surface water quality using an ecotoxicological approach: A case study of the Alqueva Reservoir (Portugal)","volume":"17","author":"Palma","year":"2010","journal-title":"Environ. Sci. Pollut. Res."},{"key":"ref_68","unstructured":"Bukata, R.P., Jerome, J.H., Kondratyev, K.Y., and Pozdnyakov, D.V. (1995). Optical Properties and Remote Sensing of Inland and Coastal Waters, CRS Press."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/5\/768\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:02:37Z","timestamp":1760173357000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/5\/768"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,28]]},"references-count":68,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,3]]}},"alternative-id":["rs12050768"],"URL":"https:\/\/doi.org\/10.3390\/rs12050768","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,28]]}}}