{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T16:07:33Z","timestamp":1780589253495,"version":"3.54.1"},"reference-count":52,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,5,16]],"date-time":"2018-05-16T00:00:00Z","timestamp":1526428800000},"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>Although optical remote sensing can intuitively detect algal bloom, it is limited by the weather conditions. Synthetic aperture radar (SAR) is not affected by inadequate weather conditions. According to visual interpretation of SAR images and comparisons of quasi-synchronized optical images, the gathering areas of algal bloom present as \u201cdark regions\u201d on SAR images. It is shown that using SAR to monitor the water surface is workable. However, dark regions may also be caused by other factors, such as low wind speeds. This challenges with SAR monitoring of algal bloom on the water surface. In this study, an improved K-means algorithm, combined with multi-Otsu thresholding algorithm, was proposed to segment the dark regions. After feature analysis and extraction of Sentinel-1A images, an algal bloom recognition model with a support vector machine (SVM) was applied to discriminate the algal bloom dark regions from the low wind dark regions. According the experimental results, the overall accuracy achieved 74.00% in Taihu Lake. Additionally, this method was also validated in Chaohu Lake and Danjiangkou Reservoir. Therefore, it can be concluded that SAR can provide a new technical means for monitoring algal bloom of inland lakes, particularly when it is cloudy and unsuitable for optical remote sensing. To obtain more information about algal bloom, multi-band and multi-polarization SAR images can be considered for future.<\/jats:p>","DOI":"10.3390\/rs10050767","type":"journal-article","created":{"date-parts":[[2018,5,17]],"date-time":"2018-05-17T03:49:29Z","timestamp":1526528969000},"page":"767","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":37,"title":["Discrimination of Algal-Bloom Using Spaceborne SAR Observations of Great Lakes in China"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2211-2965","authenticated-orcid":false,"given":"Lin","family":"Wu","sequence":"first","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"},{"name":"College of Environment and Planning, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Le","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lin","family":"Min","sequence":"additional","affiliation":[{"name":"Network Information Center Office, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Hou","sequence":"additional","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhengwei","family":"Guo","sequence":"additional","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"},{"name":"Laboratory of Spatial Information Processing, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianhui","family":"Zhao","sequence":"additional","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"},{"name":"Laboratory of Spatial Information Processing, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4358-6449","authenticated-orcid":false,"given":"Ning","family":"Li","sequence":"additional","affiliation":[{"name":"College of Computer and Information Engineering, Henan University, Kaifeng 475004, China"},{"name":"Laboratory of Spatial Information Processing, Henan University, Kaifeng 475004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1023\/A:1018355905598","article-title":"Possible cytotoxic effects of the dinoflagellate, Gyrodinium aureolum, on juvenile bivalve molluscs","volume":"5","author":"Smolowitz","year":"1997","journal-title":"Aquac. Int."},{"key":"ref_2","first-page":"1166","article-title":"Doing battle with the green monster of Taihu Lake","volume":"317","author":"Guo","year":"2007","journal-title":"J. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Whitton, B.A., and Potts, M. (2002). Freshwater Blooms. the Ecology of Cyanobacteria: Their Diversity in Time and Space, Kluwer.","DOI":"10.1007\/0-306-46855-7"},{"key":"ref_4","first-page":"759","article-title":"Dynamic characteristics and mechanism of \u201coutbreak\u201d of cyanobacteria bloom in Taihu","volume":"61","author":"Qin","year":"2016","journal-title":"Sci. China Press"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"357","DOI":"10.18307\/2007.0401","article-title":"On the cause of cyanophyta bloom and pollution in water intake area and emergency measures in Meiliang Bay, Lake Taihu in 2007","volume":"19","author":"Kong","year":"2007","journal-title":"J. Lake Sci."},{"key":"ref_6","first-page":"2555","article-title":"Identification model of algal bloom based on the relationship between visible light and near infrared reflectance","volume":"50","author":"Li","year":"2005","journal-title":"J. Chin. Sci. Bull."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"191","DOI":"10.18307\/2008.0209","article-title":"Detecting modes of cyanobacteria bloom using MODIS data in Lake Taihu","volume":"20","author":"Xu","year":"2008","journal-title":"J. Lake Sci."},{"key":"ref_8","first-page":"254","article-title":"Quantitative estimation of phycocyanin concentration using MODIS imagery during the period of cynobacterial blooming in Taihu Lake","volume":"29","author":"Ma","year":"2009","journal-title":"China Environ. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"203","DOI":"10.18307\/2008.0211","article-title":"Monitoring cyanobacteria bloom based on MODIS data in Lake Taihu","volume":"20","author":"Zhou","year":"2008","journal-title":"J. Lake Sci."},{"key":"ref_10","first-page":"9","article-title":"Application of EOS\/MODIS Data for Research of Cyanobacteria Bloom Spatio- temporal Distribution in Taihu Lake","volume":"22","author":"Jin","year":"2009","journal-title":"Environ. Sci. Technol."},{"key":"ref_11","unstructured":"Lv, K. (2015). Remote Sensing Monitoring of Alage in Taihu Lake and its Early Warning. [Master\u2019s Thesis, University of Geosciences]."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2118","DOI":"10.1016\/j.rse.2009.05.012","article-title":"A novel ocean color index to detect floating algae in the global oceans","volume":"113","author":"Hu","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_13","unstructured":"Guo, W.C. (2011). Study on Extraction methods of cyanophytes bloom based on HJ-1. [Master\u2019s Thesis, Nanjing Normal University]."},{"key":"ref_14","unstructured":"Zhang, W., Zhao, Y.L., Xue, Y., and Liu, F.J. (2014). Research on the Spatial-Temporal Changes of Water Blooms in Dongting Lake Based on MODIS Data of 2000\u20132013 in China. Comput. Telecommun., 33\u201335."},{"key":"ref_15","first-page":"1081","article-title":"Estimating Chlorophyll-A Concentration in Poyang Lake using MODIS based on Measured Reflectance Spectra","volume":"22","author":"Zhang","year":"2013","journal-title":"Resour. Environ. Yangtze Basin"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"718","DOI":"10.18307\/2016.0404","article-title":"Monitoring the cyanobacterial blooms based on remote sensing in Lake Erhai by FAI","volume":"28","author":"Zhang","year":"2016","journal-title":"J. Lake Sci."},{"key":"ref_17","first-page":"144","article-title":"Monitoring of Enteromorpha prolifera and analysis of impact factors based on MODIS data in Rizhao offshore","volume":"28","author":"Sun","year":"2016","journal-title":"Remote Sens. Land Resour."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"012006","DOI":"10.1117\/1.JRS.11.012006","article-title":"Synthetic aperture radar detection and characteristic analysis of cyanobacterial scum in Lake Taihu","volume":"11","author":"Wang","year":"2017","journal-title":"J. Appl. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"830","DOI":"10.1038\/205830b0","article-title":"Slicks associated with Trichodesmium Blooms in the Sargasso Sea","volume":"205","author":"Sieburth","year":"1965","journal-title":"Nature"},{"key":"ref_20","first-page":"1987","article-title":"The damping of ocean surface waves by monomolecular sea slicks measured by airborne multi-frequency radars during the SAXON-FPN experiment","volume":"4","author":"Alpers","year":"2002","journal-title":"Int. Geosci. Remote Sens. Symp."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Gade, M., H\u00fchnerfuss, H., and Korenowski, G.M. (2006). On the Imaging of Biogenic and Anthropogenic Surface Films on the Sea by Radar Sensors, Springer.","DOI":"10.1007\/3-540-33271-5"},{"key":"ref_22","first-page":"54","article-title":"Range Extraction of Alage Bloom Water Body on ASAR and MODIS","volume":"3","author":"Wang","year":"2009","journal-title":"Remote Sens. Inf."},{"key":"ref_23","unstructured":"Wang, G.L. (2015). Active and passive remote sensing of inland waters cyanobacteria bloom-Taking Taihu as an example. [Master\u2019s Thesis, East China Normal University]."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.rse.2013.07.040","article-title":"Monitoring blooms and surface accumulation of cyanobacteria in the Curonian Lagoon by combining MERIS and ASAR data","volume":"146","author":"Bresciani","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_25","first-page":"799","article-title":"Lake status major problems and protection strategy in China","volume":"22","author":"Yang","year":"2010","journal-title":"J. Lake Sci."},{"key":"ref_26","first-page":"896","article-title":"Drinking Water Crisis Caused by Eutrophication and Cyanobacterial Bloom in Lake Taihu: Cause and Measurement","volume":"22","author":"Qin","year":"2007","journal-title":"J. Adv. Earth Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"687","DOI":"10.18307\/2008.0605","article-title":"Spatio-temporal distribution of cyanobacterial blooms based on satellite imageries in Lake Taihu, China","volume":"20","author":"Ma","year":"2008","journal-title":"J. Lake Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"60","DOI":"10.3808\/jei.201500296","article-title":"Water quality characteristics and integrated assessment based on multistep correlation analysis in the Danjiangkou reservoir, China","volume":"25","author":"Tan","year":"2015","journal-title":"J. Environ. Inf."},{"key":"ref_29","first-page":"26","article-title":"Present Conditions and Development of Dam Safety Monitoring and Control Researches Home and Abroad","volume":"18","author":"Yang","year":"2002","journal-title":"J. Xi\u2019an Univ. Technol."},{"key":"ref_30","first-page":"202","article-title":"Water Environmental Assessment for the Danjiangkou Reservoir","volume":"15","author":"Cheng","year":"2008","journal-title":"Res. Soil Water Conserv."},{"key":"ref_31","first-page":"1","article-title":"Main Eco-Environmental Problems and Revegetation in the Danjiangkou Reservoir Water Supplying Area of the Middle Route of the South to North Water Transfer Project","volume":"3","author":"Li","year":"2008","journal-title":"China Rural Water Hydropower"},{"key":"ref_32","first-page":"44","article-title":"Risk analysis of synchronous asynchronous encounter probability of rich-poor precipitation in the Middle Route of South-to-North Water","volume":"22","author":"Kang","year":"2011","journal-title":"J. Adv. Water Sci."},{"key":"ref_33","unstructured":"Zhang, H.N. (2017). The Basis of Interpretation of SAR Image Interpretation, Science Press."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1109\/38.135886","article-title":"Color scales for image data","volume":"12","author":"Levkowitz","year":"1992","journal-title":"IEEE Comput. Appl."},{"key":"ref_35","first-page":"1406","article-title":"Monitor of Cyanobacteria Bloom in Lake Taihu from 2001 to 2013 Based on MODIS Temporal Spectral Data","volume":"36","author":"Li","year":"2016","journal-title":"Spectrosc. Spectr. Anal."},{"key":"ref_36","first-page":"589","article-title":"Hypothesis on cyanobacteria bloom-forming mechanism in large shallow eutrophic lakes","volume":"25","author":"Kong","year":"2005","journal-title":"Acta Ecol. Sin."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"314","DOI":"10.18307\/2009.0302","article-title":"The theory and practice of prevention, forecast and warning on cyanobacteria bloom in Lake Taihu","volume":"21","author":"Kong","year":"2009","journal-title":"J. Lake Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"67","DOI":"10.18307\/1996.0109","article-title":"Algal bloom in Taihu Lake and it\u2019s control","volume":"8","author":"Yang","year":"1996","journal-title":"J. Lake Sci."},{"key":"ref_39","first-page":"57","article-title":"Importation of Wind-Driven Drift of Mat-Like Algae Bloom into Meiliang Bay of Taihu Lake in 2004 Summer","volume":"26","author":"Bai","year":"2005","journal-title":"Environ. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1109\/TSMC.1979.4310076","article-title":"A threshold selection method from gray-level histograms","volume":"9","author":"Ohtsu","year":"1979","journal-title":"IEEE Trans. Syst. Man Cybern."},{"key":"ref_41","first-page":"35","article-title":"An adaptive K-means clustering algorithm for breast image segmentation","volume":"10","author":"Patel","year":"2010","journal-title":"Int. J. Comput. Appl."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"386","DOI":"10.4028\/www.scientific.net\/AMM.530-531.386","article-title":"An Efficient Algorithm Optimization of CT Images Segmentation Based on K-Means Clustering","volume":"530","author":"Ma","year":"2014","journal-title":"Appl. Mech. Mater."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2145","DOI":"10.1109\/TCE.2009.5373781","article-title":"Adaptive fuzzy moving K-means clustering algorithm for image segmentation","volume":"55","author":"Isa","year":"2009","journal-title":"J. Consumer Electron. IEEE Trans."},{"key":"ref_44","first-page":"195","article-title":"GLCM-based texture feature extraction","volume":"19","author":"Gao","year":"2010","journal-title":"Comput. Syst. Appl."},{"key":"ref_45","unstructured":"Peng, L. (2007). Research on Classification Algorithm of Support Vector Machine and It Application. [Master\u2019s Thesis, Hunan University]."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Vapnik, V.N. (1995). The Nature of Statistical Learning Theory, Springer.","DOI":"10.1007\/978-1-4757-2440-0"},{"key":"ref_47","unstructured":"Vapnik, V.N. (1998). Statistical Learning Theory, Wiley-Interscience Wiley."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1023\/A:1009715923555","article-title":"A tutorial on support vector machines for pattern recognition","volume":"2","author":"Burges","year":"1998","journal-title":"Data Min. Knowl. Discov."},{"key":"ref_49","first-page":"1","article-title":"Classification using intersection kernel support vector machines is efficient","volume":"21","author":"Ma","year":"2008","journal-title":"Comput. Vis. Pattern Recogn. J. IEEE"},{"key":"ref_50","first-page":"2758","article-title":"Comparing support vector machines with Gaussian kernels to radial basis function classifiers","volume":"45","author":"Scholkopf","year":"1997","journal-title":"J. Signal Process."},{"key":"ref_51","unstructured":"Weston, J., and Watkins, C. (2005). Multiclass Support Vector Machines, Springer."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1177\/001316446002000104","article-title":"coefficient agreement for nominal data","volume":"2","author":"Cohen","year":"1960","journal-title":"Educ. Psychol. Meas."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/5\/767\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:04:31Z","timestamp":1760195071000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/5\/767"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,5,16]]},"references-count":52,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2018,5]]}},"alternative-id":["rs10050767"],"URL":"https:\/\/doi.org\/10.3390\/rs10050767","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,5,16]]}}}