{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T14:56:54Z","timestamp":1770821814792,"version":"3.50.1"},"reference-count":55,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,4,8]],"date-time":"2021-04-08T00:00:00Z","timestamp":1617840000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Chinese Academy of Sciences Strategic Leading Special A &quot;Earth Big Data Science Project&quot;","award":["XDA19060300"],"award-info":[{"award-number":["XDA19060300"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Coastal tidal flats are important ecological resources. As the dividing line between marine and terrestrial ecosystems, tidal flats provide a large number of ecosystem services. However, with the excessive development of coastal areas, tidal flat resources have been drastically reduced, leading to the deterioration of coastal ecosystems. There is an urgent need to acquire accurate information on the changes in tidal flat resources. This research proposes a tidal flat extraction model (RF-W model) that combines the random forest (RF) method and waterline method, which aims to improve the accuracy of tidal flat extraction. This method can effectively eliminate the shortcomings of the RF method in determining the lower boundary of tidal flats and those of the waterline method in distinguishing river channels and tidal flats. The tidal flat extraction of Qingdao Jiaozhou Bay in 2020 is performed as an example of the model. The results show that the user\u2019s and producer\u2019s accuracies of the RF-W model were both the highest, indicating that the improved model can accurately extract tidal flat information. Then, we used the RF-W model to extract tidal flat information for Jiaozhou Bay in seven periods (1990, 1995, 2000, 2005, 2010, 2015, and 2020) and to study the spatiotemporal changes in the tidal flats and influencing factors from 1990 to 2020. The tidal flat area of Jiaozhou Bay showed an overall downward trend before 2015, and the area decreased by 21.9 km2, with a reduction in the rate of approximately 1.1%\/year. After 2015, the tidal flat area rebounded slightly. The overall change in Jiaozhou Bay showed reclamation and expansion toward the sea. The reduction in the sand content of the rivers entering the sea, reclamation and cultivation, and land development were the main factors contributing to the reduction in the tidal flat area in Jiaozhou Bay. In addition, sea level rise due to climate warming is a long-term potential factor.<\/jats:p>","DOI":"10.3390\/rs13081436","type":"journal-article","created":{"date-parts":[[2021,4,8]],"date-time":"2021-04-08T21:27:44Z","timestamp":1617917264000},"page":"1436","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Tidal Flat Extraction and Change Analysis Based on the RF-W Model: A Case Study of Jiaozhou Bay, East China"],"prefix":"10.3390","volume":"13","author":[{"given":"Jinfeng","family":"Yan","sequence":"first","affiliation":[{"name":"College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China"}]},{"given":"Shiyi","family":"Zhao","sequence":"additional","affiliation":[{"name":"College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China"}]},{"given":"Fenzhen","family":"Su","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100864, China"}]},{"given":"Jiaxue","family":"Du","sequence":"additional","affiliation":[{"name":"College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China"}]},{"given":"Pengfei","family":"Feng","sequence":"additional","affiliation":[{"name":"College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China"}]},{"given":"Shixun","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, China"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,8]]},"reference":[{"key":"ref_1","unstructured":"Li, C., Wang, P., and Fan, D. (2005). Tidal flats, open ocean coasts. Encyclopedia of Coastal Science, Springer."},{"key":"ref_2","unstructured":"Millennium Ecosystem Assessment, M.E.A. (2005). Ecosystems and Human Well-Being, Island Press."},{"key":"ref_3","first-page":"584","article-title":"A Global Analysis of Human Settlement in Coastal Zones","volume":"19","author":"Small","year":"2003","journal-title":"J. Coast. Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.ecss.2016.01.006","article-title":"Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010","volume":"170","author":"Tian","year":"2016","journal-title":"Estuar. Coast. Shelf Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1126\/science.1257258","article-title":"Rethinking China\u2019s new great wall","volume":"346","author":"Ma","year":"2014","journal-title":"Science"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Tong, S.S., Deroin, J.P., and Pham, T.L. (2020). An optimal waterline approach for studying tidal flat morphological changes using remote sensing data: A case of the northern coast of Vietnam. Estuar. Coast. Shelf Sci., 236.","DOI":"10.1016\/j.ecss.2020.106613"},{"key":"ref_7","first-page":"269","article-title":"Monitoring tidal flats in the Yangtze River Delta using Landsat images","volume":"21","author":"Qiu","year":"2019","journal-title":"J. Geo-Inf. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1111\/aec.12211","article-title":"Tidal flats of the Yellow Sea: A review of ecosystem status and anthropogenic threats","volume":"40","author":"Murray","year":"2015","journal-title":"Austral Ecol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"302","DOI":"10.1016\/j.jhydrol.2010.07.030","article-title":"Recent changes in sediment delivery by the Huanghe (Yellow River) to the sea: Causes and environmental implications in its estuary","volume":"391","author":"Wang","year":"2010","journal-title":"J. Hydrol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Zhang, K.Y., Dong, X.Y., Liu, Z.G., Gao, W.X., Hu, Z.W., and Wu, G.F. (2019). Mapping Tidal Flats with Landsat 8 Images and Google Earth Engine: A Case Study of the China\u2019s Eastern Coastal Zone circa 2015. Remote Sens., 11.","DOI":"10.3390\/rs11080924"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5123","DOI":"10.1109\/JSTARS.2016.2616514","article-title":"An Improved Method for Mapping Tidal Flats Based on Remote Sensing Waterlines: A Case Study in the Bohai Rim, China","volume":"9","author":"Liu","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhao, Y., Liu, Q., Huang, R., Pan, H., and Xu, M. (2020). Recent Evolution of Coastal Tidal Flats and the Impacts of Intensified Human Activities in the Modern Radial Sand Ridges, East China. Int. J. Environ. Res. Public Health, 17.","DOI":"10.3390\/ijerph17093191"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1016\/S0034-4257(02)00059-7","article-title":"Waterline extraction from Landsat TM data in a tidal flat: A case study in Gomso Bay, Korea","volume":"83","author":"Ryu","year":"2002","journal-title":"Remote Sens. Environ."},{"key":"ref_14","first-page":"165","article-title":"Detecting coastline change from satellite images based on beach slope estimation in a tidal flat","volume":"23","author":"Liu","year":"2013","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1016\/j.isprsjprs.2017.07.008","article-title":"Reconstruction of time-varying tidal flat topography using optical remote sensing imageries","volume":"131","author":"Tseng","year":"2017","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/j.rse.2017.04.009","article-title":"Extracting the intertidal extent and topography of the Australian coastline from a 28 year time series of Landsat observations","volume":"195","author":"Sagar","year":"2017","journal-title":"Remote Sens. Environ."},{"key":"ref_17","first-page":"262","article-title":"Spatiotemporal shoreline dynamics of Namibian coastal lagoons derived by a dense remote sensing time series approach","volume":"68","author":"Behling","year":"2018","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Wang, X., Xiao, X., Zou, Z., Chen, B., Ma, J., Dong, J., Doughty, R.B., Zhong, Q., Qin, Y., and Dai, S. (2020). Tracking annual changes of coastal tidal flats in China during 1986\u20132016 through analyses of Landsat images with Google Earth Engine. Remote Sens. Environ., 238.","DOI":"10.1016\/j.rse.2018.11.030"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.rse.2014.04.004","article-title":"A 2010 update of National Land Use\/Cover Database of China at 1:100000 scale using medium spatial resolution satellite images","volume":"149","author":"Zhang","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1038\/s41586-018-0805-8","article-title":"The global distribution and trajectory of tidal flats","volume":"565","author":"Murray","year":"2019","journal-title":"Nature"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/j.envsoft.2018.01.023","article-title":"A new synergistic approach for monitoring wetlands using Sentinels -1 and 2 data with object-based machine learning algorithms","volume":"104","author":"Whyte","year":"2018","journal-title":"Environ. Model. Softw."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Dubeau, P., King, D.J., Unbushe, D.G., and Rebelo, L.-M. (2017). Mapping the Dabus Wetlands, Ethiopia, Using Random Forest Classification of Landsat, PALSAR and Topographic Data. Remote Sens., 9.","DOI":"10.3390\/rs9101056"},{"key":"ref_23","first-page":"44","article-title":"Information Extraction of Wetlands in Typical Oasis Based on Random Forest Model","volume":"6","author":"Gu","year":"2019","journal-title":"China Rural Water Hydropower"},{"key":"ref_24","first-page":"220","article-title":"Land Cover Remote Sensing Classification Method of Alpine Wetland Region Based on Random Forest Algorithms","volume":"7","author":"Hou","year":"2020","journal-title":"Trans. Chin. Soc. Agric. Mach."},{"key":"ref_25","unstructured":"Lin, R. (2016). Research on the Theoretical Strategy of Qingdao Ecological Environment and Landscape Protection. [Ph.D. Thesis, Beijing Forestry University]."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1249","DOI":"10.5194\/isprsarchives-XL-7-W3-1249-2015","article-title":"Calibration and validation plan for the l2A processor and products of the Sentinel-2 mission","volume":"XL-7\/W3","author":"Mackert","year":"2015","journal-title":"Int. Arch. Photogramm. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1855","DOI":"10.5194\/acp-5-1855-2005","article-title":"Technical note: The libRadtran software package for radiative transfer calculations-description and examples of use","volume":"5","author":"Mayer","year":"2005","journal-title":"Atmos. Chem. Phys."},{"key":"ref_28","first-page":"1","article-title":"The advances in the study of atmospheric correction for optical remote sensing","volume":"17","author":"Qi","year":"2005","journal-title":"Remote Sens. Land Resour."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Cao, W., Zhou, Y., Li, R., and Li, X. (2020). Mapping changes in coastlines and tidal flats in developing islands using the full time series of Landsat images. Remote Sens. Environ., 239.","DOI":"10.1016\/j.rse.2020.111665"},{"key":"ref_30","first-page":"522","article-title":"Estimation of Maximum Heterogeneity Parameters for Object-Oriented Image Multi-scale Segmentation","volume":"4","author":"Ma","year":"2017","journal-title":"J. Remote Sens."},{"key":"ref_31","first-page":"785","article-title":"Extraction of Land Use Information in Different Karst Geomorphic Areas Based on Multi-scale and Spectral Difference Segmentation of GF-1 Image","volume":"5","author":"Chen","year":"2019","journal-title":"Carsologica Sin."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1080\/13658810903174803","article-title":"ESP: A tool to estimate scale parameter for multiresolution image segmentation of remotely sensed data","volume":"24","author":"Tiede","year":"2010","journal-title":"Int. J. Geogr. Inf. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.rse.2013.08.029","article-title":"Automated Water Extraction Index: A new technique for surface water mapping using Landsat imagery","volume":"140","author":"Feyisa","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_34","first-page":"168","article-title":"Improved random forests and its application to classification of remote sensing image","volume":"52","author":"Yao","year":"2016","journal-title":"Comput. Eng. Appl."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/j.rse.2015.12.055","article-title":"Comparing Landsat water index methods for automated water classification in eastern Australia","volume":"175","author":"Fisher","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_36","unstructured":"Lu, Y., Yang, Y., Huang, P., Shu, X., and Lin, X. (2019). Method for Quickly Extracting Beach Area of Exposed Water Surface, CN201910912106.1."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/0034-4257(85)90102-6","article-title":"A TM Tasseled Cap Equivalent Transformation for Reflectance Factor Data","volume":"17","author":"Crist","year":"1985","journal-title":"Remote Sens. Environ."},{"key":"ref_38","first-page":"81","article-title":"The Tasseled Cap De-mystified","volume":"52","author":"Crist","year":"1986","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1023\/A:1010933404324","article-title":"Random forests","volume":"45","author":"Breiman","year":"2001","journal-title":"Mach. Learn."},{"key":"ref_40","first-page":"680","article-title":"Analysis of Land Use Change in Jiaozhou Bay Coastal Zone","volume":"5","author":"Pang","year":"2017","journal-title":"Wetl. Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3383","DOI":"10.1080\/014311698214055","article-title":"Detection of shoreline changes for tideland areas using multi-temporal satellite images","volume":"19","author":"Chen","year":"1998","journal-title":"Int. J. Remote Sens."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.isprsjprs.2019.11.022","article-title":"Mapping large-area tidal flats without the dependence on tidal elevations: A case study of Southern China","volume":"159","author":"Zhao","year":"2020","journal-title":"ISPRS J. Photogramm. Remote. Sens."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Chen, Y., Dong, J., Xiao, X., Zhang, M., Tian, B., Zhou, Y., and Ma, Z. (2016). Land claim and loss of tidal flats in the Yangtze Estuary. Sci. Rep., 6.","DOI":"10.1038\/srep24018"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Congalton, R.G., and Green, K. (2008). Assessing the Accuracy of Remotely Sensed Data: Principles and Practices, CRC Press.","DOI":"10.1201\/9781420055139"},{"key":"ref_45","first-page":"331","article-title":"Impact of water and sediment discharges on subaqueous delta evolution in Yangtze Estuary from 1950 to 2010","volume":"7","author":"Yang","year":"2014","journal-title":"Water Sci. Eng."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.gloplacha.2017.08.005","article-title":"Impacts of the dam-orientated water-sediment regulation scheme on the lower reaches and delta of the Yellow River (Huanghe): A review","volume":"157","author":"Wang","year":"2017","journal-title":"Glob. Planet. Chang."},{"key":"ref_47","first-page":"179","article-title":"Remote Sensing Analysis of the Present Situation of Dagu Estuary Wetland in Jiaozhou Bay","volume":"36","author":"Ma","year":"2006","journal-title":"Period. Ocean Univ. China"},{"key":"ref_48","unstructured":"Chen, Z., Wang, W., and Wu, S. (2007). Introduction to the Gulf of China.Beijing, Beijing Ocean Press."},{"key":"ref_49","first-page":"506","article-title":"Evolution process and ecological effect analysis of reclamation in Jiaozhou Bay","volume":"4","author":"Lei","year":"2013","journal-title":"Mar. Environ. Sci."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"432","DOI":"10.1016\/j.jhydrol.2014.02.013","article-title":"Shoreline change of Chongming Dongtan and response to river sediment load: A remote sensing assessment","volume":"511","author":"Li","year":"2014","journal-title":"J. Hydrol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.quaint.2007.11.018","article-title":"A preliminary estimate of human and natural contributions to the decline in sediment flux from the Yangtze River to the East China Sea","volume":"186","author":"Dai","year":"2008","journal-title":"Quat. Int."},{"key":"ref_52","first-page":"76","article-title":"The morphological response of typical mud flat to sea level change in Jiangsu coastal plain","volume":"57","author":"Yang","year":"2002","journal-title":"Acta Geographica Sinica"},{"key":"ref_53","first-page":"78","article-title":"Summary of research on the impact of estuary beach reclamation on hydrodynamic environment","volume":"40","author":"Tang","year":"2020","journal-title":"Adv. Sci. Technol. Water Resour."},{"key":"ref_54","first-page":"57","article-title":"Ecological impact of land reclamation on Jiangsu coast (China): A novel ecotope assessment for Tongzhou Bay Water","volume":"13","author":"Muller","year":"2020","journal-title":"Sci. Eng."},{"key":"ref_55","first-page":"3311","article-title":"Development trend, environmental and ecological impacts, and policy recommendations for Bohai Sea reclamation","volume":"38","author":"Hou","year":"2018","journal-title":"Acta Ecol. Sin."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/8\/1436\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:26:37Z","timestamp":1760361997000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/13\/8\/1436"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,4,8]]},"references-count":55,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,4]]}},"alternative-id":["rs13081436"],"URL":"https:\/\/doi.org\/10.3390\/rs13081436","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,4,8]]}}}