{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T15:27:44Z","timestamp":1775834864320,"version":"3.50.1"},"reference-count":51,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2019,1,18]],"date-time":"2019-01-18T00:00:00Z","timestamp":1547769600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41771472"],"award-info":[{"award-number":["41771472"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41621002"],"award-info":[{"award-number":["41621002"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012492","name":"Youth Innovation Promotion Association","doi-asserted-by":"publisher","award":["2017365"],"award-info":[{"award-number":["2017365"]}],"id":[{"id":"10.13039\/501100012492","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences","award":["QYZDB-SSW-DQC016"],"award-info":[{"award-number":["QYZDB-SSW-DQC016"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Transparency is an important indicator of water quality and the underwater light environment and is widely measured in water quality monitoring. Decreasing transparency occurs throughout the world and has become the primary water quality issue for many freshwater and coastal marine ecosystems due to eutrophication and other human activities. Lake Hongze is the fourth largest freshwater lake in China, providing water for surrounding cities and farms but experiencing significant water quality changes. However, there are very few studies about Lake Hongze\u2019s transparency due to the lack of long-term monitoring data for the lake. To understand long-term trends, possible causes and potential significance of the transparency in Lake Hongze, an empirical model for estimating transparency (using Secchi disk depth: SDD) based on the moderate resolution image spectroradiometer (MODIS) 645-nm data was validated using an in situ dataset. Model mean absolute percentage and root mean square errors for the validation dataset were 27.7% and RMSE = 0.082 m, respectively, which indicates that the model performs well for SDD estimation in Lake Hongze without any adjustment of model parameters. Subsequently, 1785 cloud-free images were selected for use by the validated model to estimate SDDs of Lake Hongze in 2003\u20132017. The long-term change of SDD of Lake Hongze showed a decreasing trend from 2007 to 2017, with an average of 0.49 m, ranging from 0.57 m in 2007 to 0.42 m in 2016 (a decrease of 26.3%), which indicates that Lake Hongze experienced increased turbidity in the past 11 years. The loss of aquatic vegetation in the northern bays may be mainly affected by decreases of SDD. Increasing total suspended matter (TSM) concentration resulting from sand mining activities may be responsible for the decreasing trend of SDD.<\/jats:p>","DOI":"10.3390\/rs11020177","type":"journal-article","created":{"date-parts":[[2019,1,18]],"date-time":"2019-01-18T02:22:23Z","timestamp":1547778143000},"page":"177","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":36,"title":["Decline in Transparency of Lake Hongze from Long-Term MODIS Observations: Possible Causes and Potential Significance"],"prefix":"10.3390","volume":"11","author":[{"given":"Na","family":"Li","sequence":"first","affiliation":[{"name":"Key Laboratory of Virtual Geographic Environment of Education Ministry, Nanjing Normal University, Nanjing 210023, China"},{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Kun","family":"Shi","sequence":"additional","affiliation":[{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"},{"name":"CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3382-4570","authenticated-orcid":false,"given":"Yunlin","family":"Zhang","sequence":"additional","affiliation":[{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Zhijun","family":"Gong","sequence":"additional","affiliation":[{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Kai","family":"Peng","sequence":"additional","affiliation":[{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Yibo","family":"Zhang","sequence":"additional","affiliation":[{"name":"Taihu Lake Laboratory Ecosystem Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Yong","family":"Zha","sequence":"additional","affiliation":[{"name":"Key Laboratory of Virtual Geographic Environment of Education Ministry, Nanjing Normal University, Nanjing 210023, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,18]]},"reference":[{"key":"ref_1","first-page":"256","article-title":"Using VIIRS\/NPP and MODIS\/Aqua data to provide a continuous record of suspended particulate matter in a highly turbid inland lake","volume":"64","author":"Cao","year":"2018","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2183","DOI":"10.1080\/01431160701422254","article-title":"Comparison of MODIS and Landsat TM5 images for mapping tempo-spatial dynamics of Secchi disk depths in Poyang Lake National Nature Reserve, China","volume":"29","author":"Wu","year":"2008","journal-title":"Int. J. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1029\/2011JC007864","article-title":"Human induced turbidity changes in Poyang Lake between 2000 and 2010: Observations from MODIS","volume":"117","author":"Feng","year":"2012","journal-title":"J. Geophys. Res. Oceans"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6448","DOI":"10.1021\/es505901a","article-title":"Long-term satellite observations of microcystin concentrations in Lake Taihu during cyanobacterial bloom periods","volume":"49","author":"Shi","year":"2015","journal-title":"Environ. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1847","DOI":"10.1111\/fwb.13000","article-title":"Recovery of lake vegetation following reduced eutrophication and acidification","volume":"62","author":"Olesen","year":"2017","journal-title":"Freshw. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.limno.2017.10.006","article-title":"Bloom-forming cyanobacteria and cyanotoxins in Argentina: A growing health and environmental concern","volume":"69","author":"Aguilera","year":"2018","journal-title":"Limnologica"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1016\/j.jhazmat.2015.01.047","article-title":"Cyanobacterial bloom management through integrated monitoring and forecasting in large shallow eutrophic Lake Taihu (China)","volume":"287","author":"Qin","year":"2015","journal-title":"J. Hazard. Mater."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"23867","DOI":"10.1038\/srep23867","article-title":"Aquatic vegetation in response to increased eutrophication and degraded light climate in Eastern Lake Taihu: Implications for lake ecological restoration","volume":"6","author":"Zhang","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.earscirev.2017.08.013","article-title":"Global loss of aquatic vegetation in lakes","volume":"173","author":"Zhang","year":"2017","journal-title":"Earth-Sci. Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1016\/j.ecolind.2017.02.007","article-title":"Improved retrieval of Secchi depth for optically-complex waters using remote sensing data","volume":"77","author":"Alikas","year":"2017","journal-title":"Ecol. Indic."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/j.rse.2017.06.018","article-title":"Retrieval of Secchi disk depth from a reservoir using a semi-analytical scheme","volume":"198","author":"Rodrigues","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_12","first-page":"194","article-title":"Optical water quality: What does it mean and how should we measure it?","volume":"60","author":"Kirk","year":"1988","journal-title":"Water Pollut. Control Fed."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"326","DOI":"10.2307\/1468419","article-title":"Comparison of methods for measuring visual water clarity","volume":"21","author":"Steel","year":"2002","journal-title":"J. N. Am. Benthol. Soc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2986","DOI":"10.1016\/j.rse.2011.05.019","article-title":"Ocean transparency from space: Validation of algorithms estimating secchi depth using MERIS, MODIS and SeaWiFS data","volume":"115","author":"Doron","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1007\/s10750-012-1084-2","article-title":"Predicting the light attenuation coefficient through Secchi disk depth and beam attenuation coefficient in a large, shallow, freshwater lake","volume":"693","author":"Zhang","year":"2012","journal-title":"Hydrobiologia"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1080\/07438148409354553","article-title":"Trophic state indices: Rational for multivariate approaches","volume":"1","author":"Brezonik","year":"1984","journal-title":"Lake Reserv. Manag."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"361","DOI":"10.4319\/lo.1977.22.2.0361","article-title":"A trophic state index for lakes","volume":"22","author":"Carlson","year":"1977","journal-title":"Limnol. Oceanogr."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1002\/jgrg.20054","article-title":"Wind and submerged aquatic vegetation influence bio-optical properties in large shallow Lake Taihu, China","volume":"118","author":"Liu","year":"2013","journal-title":"J. Geophys. Res. Biogeosci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.rse.2016.08.020","article-title":"Changes in water clarity of the Bohai Sea: Observations from MODIS","volume":"186","author":"Shang","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_20","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_21","doi-asserted-by":"crossref","first-page":"748","DOI":"10.1111\/jawr.12138","article-title":"Geospatial and temporal analysis of a 20-year record of Landsat-based water clarity in Minnesota\u2019s 10,000 Lakes","volume":"50","author":"Olmanson","year":"2014","journal-title":"JAWRA J. Am. Water Resour. Assoc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2206","DOI":"10.1111\/gcb.12854","article-title":"Decrease in water clarity of the southern and central North Sea during the 20th century","volume":"21","author":"Capuzzo","year":"2015","journal-title":"Glob. Chang. Biol."},{"key":"ref_23","first-page":"287","article-title":"Deteriorating water clarity in shallow waters: Evidence from long term MODIS and in-situ observations","volume":"68","author":"Shi","year":"2018","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4319\/lo.1968.13.1.0001","article-title":"The secchi disc","volume":"13","author":"Tyler","year":"1968","journal-title":"Limnol. Oceanogr."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.rse.2016.02.033","article-title":"A semi-analytical scheme to estimate Secchi-disk depth from Landsat-8 measurements","volume":"177","author":"Lee","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Al Kaabi, M., Zhao, J., and Ghedira, H. (2016). MODIS-based mapping of Secchi disk depth using a qualitative algorithm in the shallow Arabian Gulf. Remote Sens., 8.","DOI":"10.3390\/rs8050423"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"A1","DOI":"10.1016\/j.ecss.2016.03.001","article-title":"Changes in water clarity in response to river discharges on the Great Barrier Reef continental shelf: 2002\u20132013","volume":"173","author":"Fabricius","year":"2016","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1016\/j.rse.2013.03.016","article-title":"MODIS-derived spatiotemporal water clarity patterns in optically shallow Florida Keys waters: A new approach to remove bottom contamination","volume":"134","author":"Barnes","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/j.rse.2015.08.002","article-title":"Secchi disk depth: A new theory and mechanistic model for underwater visibility","volume":"169","author":"Lee","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1016\/j.rse.2017.02.007","article-title":"Climate- and human-induced changes in suspended particulate matter over Lake Hongze on short and long timescales","volume":"192","author":"Cao","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1007\/s10661-010-1590-5","article-title":"Evaluation of water quality and management of Hongze Lake and Gaoyou Lake along the Grand Canal in Eastern China","volume":"176","author":"Li","year":"2011","journal-title":"Environ. Monit. Assess."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Wu, Y., Dai, R., Xu, Y., Han, J., and Li, P. (2018). Statistical assessment of water quality issues in Hongze Lake, China, related to the operation of a water diversion project. Sustainability, 10.","DOI":"10.3390\/su10061885"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"606","DOI":"10.1016\/j.scitotenv.2018.07.359","article-title":"Detection of illicit sand mining and the associated environmental effects in China\u2019s fourth largest freshwater lake using daytime and nighttime satellite images","volume":"647","author":"Duan","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_34","first-page":"49","article-title":"Analysis on sand mining management in Hongze Lake","volume":"30","author":"Yan","year":"2015","journal-title":"Jiangsu Sci. Technol. Inf."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1698","DOI":"10.1016\/j.jhydrol.2014.09.058","article-title":"Sand mining and increasing Poyang Lake\u2019s discharge ability: A reassessment of causes for lake decline in China","volume":"519","author":"Lai","year":"2014","journal-title":"J. Hydrol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"342","DOI":"10.1002\/hyp.7163","article-title":"Monitoring the impact of backflow and dredging on water clarity using MODIS images of Poyang Lake, China","volume":"23","author":"Cui","year":"2009","journal-title":"Hydrol. Process."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3271","DOI":"10.1016\/j.watres.2007.05.018","article-title":"Concurrent monitoring of vessels and water turbidity enhances the strength of evidence in remotely sensed dredging impact assessment","volume":"41","author":"Wu","year":"2007","journal-title":"Water Res."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"63","DOI":"10.18307\/1992.0108","article-title":"Aquatic vegetation in Hongze Lake","volume":"4","author":"Zhang","year":"1992","journal-title":"J. Lake Sci."},{"key":"ref_39","first-page":"1","article-title":"Aquatic macrophyte status and variation characteristics in the past 50 years in Hongzehu Lake","volume":"2","author":"Liu","year":"2009","journal-title":"J. Hydroecol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"073589","DOI":"10.1117\/1.JRS.7.073589","article-title":"Changes in vegetative coverage of the Hongze Lake national wetland nature reserve: A decade-long assessment using MODIS medium-resolution data","volume":"7","author":"Yu","year":"2013","journal-title":"J. Appl. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Ruan, R., and Li, Z. (2010, January 23\u201325). Changes of Hongze Lake wetlands in the past three decades. Proceedings of the 6th International Conference on Wireless Communications NETWORKING and Mobile Computing, Shenzhen, China.","DOI":"10.1109\/WICOM.2010.5601034"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1109\/JSTARS.2015.2503800","article-title":"An improved land target-based atmospheric correction method for Lake Taihu","volume":"9","author":"Liu","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"9093","DOI":"10.1080\/01431161.2010.549850","article-title":"Identification and quantification of aquatic vegetation with hyperspectral remote sensing in western Nevada rivers, USA","volume":"32","author":"Lee","year":"2011","journal-title":"Int. J. Remote Sens."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"10295","DOI":"10.3390\/rs70810295","article-title":"Mapping aquatic vegetation in a Large, shallow eutrophic lake: A frequency-based approach using multiple years of MODIS data","volume":"7","author":"Liu","year":"2015","journal-title":"Remote Sens."},{"key":"ref_45","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_46","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1007\/s11430-006-8111-y","article-title":"Effect of sediment resuspension on underwater light field in shallow lakes in the middle and lower reaches of the Yangtze River: A case study in Longgan Lake and Taihu Lake","volume":"49","author":"Zhang","year":"2006","journal-title":"Sci. China Ser. D"},{"key":"ref_47","first-page":"150","article-title":"Exploration of conceptual model of nutrient release from inner source in large shallow lake","volume":"22","author":"Qin","year":"2002","journal-title":"China Environ. Sci."},{"key":"ref_48","first-page":"30","article-title":"Analysis and potential countermeasures of water pollution in Hongze Lake from 1991 to 2005","volume":"8","author":"Yin","year":"2009","journal-title":"Jiangsu Water Resour."},{"key":"ref_49","first-page":"355","article-title":"Study of morphologic change in Poyang Lake basin caused by sand dredging using multi-temporal Landsat images and DEMs","volume":"XL-1","author":"Qi","year":"2014","journal-title":"ISPRS Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"6004","DOI":"10.1080\/01431161.2014.939783","article-title":"Remote-sensing monitoring for spatio-temporal dynamics of sand dredging activities at Poyang Lake in China","volume":"35","author":"Li","year":"2014","journal-title":"Int. J. Remote Sens."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1007\/s10021-009-9277-x","article-title":"Effects of submerged vegetation on water clarity across climates","volume":"12","author":"Kosten","year":"2009","journal-title":"Ecosystems"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/2\/177\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:26:58Z","timestamp":1760185618000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/2\/177"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,1,18]]},"references-count":51,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2019,1]]}},"alternative-id":["rs11020177"],"URL":"https:\/\/doi.org\/10.3390\/rs11020177","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,1,18]]}}}