Extraction and spatio-temporal change analysis of the tidal flat in Cixi section of Hangzhou Bay based on Google Earth Engine
ZHENG Xiucheng1,2,3(), ZHOU Bin1,2,3(), LEI Hui1,2,3, HUANG Qiyu3, YE Haolin3
1. Institute of Remote Sensing and Earth Science, Hangzhou Normal University, Hangzhou 311121, China 2. Zhejiang Provincial Key Laboratory of Urban Wetlands and Regional Change, Hangzhou 311121, China 3. School of Information Science and Technology, Hangzhou Normal University, Hangzhou 311121, China
At present, the common methods for extracting tidal flats using remote sensing images tend to estimate tidal flat boundaries. Therefore, it is difficult to ensure high extraction accuracy. This study combined remote sensing cloud computing platform Google Earth Engine with the geographic information system (GIS) technology and selected 77 Landsat images during 1990—2021. Meanwhile, the mean high-tide line was set to the artificial coastline obtained through visual interpretation, and the mean low-tide line was determined through the fitting of the shoreline. Based on these, this study extracted the tidal flat in the Cixi section on the south bank of the Hangzhou Bay and estimated its area. Furthermore, this study analyzed the spatio-temporal changes in the area of the tidal flat. The results are as follows. During 1990—2021, the area of the tidal flat in the Cixi section on the south bank of the Hangzhou Bay was roughly maintained in the range of 20 000~24 000 hm2, and the tidal flat migrated from south to north at a speed of 286.9 m·a-1. The main driving force behind the spatial and area changes of the tidal flat was local policies.
Xiucheng ZHENG,Bin ZHOU,Hui LEI, et al. Extraction and spatio-temporal change analysis of the tidal flat in Cixi section of Hangzhou Bay based on Google Earth Engine[J]. Remote Sensing for Natural Resources,
2022, 34(1): 18-26.
Zhang C G. The application of MODIS data in tidal flat resource monitoring of coastal zone of Fujian Province in China[J]. Acta Oceonlolgica Sinica, 2007(4):51-58.
Wang X L, Zhang J, Chu J L. Extraction of remotely sensed information of island intertidal zone and wetland:Taking the Dongsha Island as an example[J]. Advances in Marine Science, 2005(4)477-481.
Han Q Q, Niu Z G, Wu M Q, et al. Remote-sensing monitoring and analysis of China intertidal zone changes based on tidal correction[J]. Chinese Science Bulletin, 2019, 64(4):456-473.
Zhang Y Y, Gao Z Q, Liu X Y, et al. The extraction method of tidal flat area based on remote sensing waterlines[J]. Ocean Development and Management, 2018, 35(3):56-61.
[9]
胡允和, 施德忠. 慈溪海涂促淤浅析[J]. 浙江水利科技, 1984(2):22-32.
[9]
Hu Y H, Shi D Z. Brief analysis of Cixi sea flat to promote sedimentation[J]. Zhejiang Hydrotechnics, 1984(2):22-32.
Wang L J, Li J L, Tian P, et al. Impacts of human activity on coastal wetland land cover changes related to reclamation on the south coast of Hangzhou Bay[J]. Shanghai Land and Resources, 2020, 41(1):4-10.
[11]
韩茜. 基于遥感技术的我国潮滩资源现状研究[D]. 南京: 南京师范大学, 2011.
[11]
Han Q. Research on the status of tidal resources in China using remote sensing technology[D]. Nanjing:Nanjing Normal University, 2011.
Zhang Z D, Xiao J C. The application of remote sensing to investigate tidal flat evolution[J]. Remote Sensing for Land and Resources, 1995, 7(3):25-28.doi: 10.6046/gtzyyg.1995.03.05.
doi: 10.6046/gtzyyg.1995.03.05
[13]
赵明才, 章大初. 海岸线定义问题的讨论[J]. 海岸工程, 1990(z1):91-99.
[13]
Zhao M C, Zhang D C. Discussions on the definition of shoreline[J]. Coastal Engineering, 1990(z1):91-99.
Wu Y Q, Liu Z L. Research progress on methods of automatic coastline extraction based on remote sensing images[J]. Journal of Remote Sensing, 2019, 23(4):582-602.
[16]
杨修国. 图像阈值分割方法研究与分析[D]. 上海: 华东师范大学, 2009.
[16]
Yang X G. Threshold image segmentation research and analysis[D]. Shanghai:East China Normal University, 2009.
Rao P, Wang J L. Water extraction based on the optimal subregion and the optimal indexes combined[J]. Journal of Geo-Information Science, 2017, 19(5):702-712.
[20]
陈星壮. 基于高分辨率遥感影像的城市水体提取算法研究[D]. 成都: 电子科技大学, 2021.
[20]
Chen X Z. Urban open water extraction from high resolution remote sensing images[D]. Chengdu:University of Electronic Science and Technology of China, 2021.
Thieler E, Himmelstoss E, Zichichi J, et al. The Digital Shoreline Analysis System (DSAS) Version 4.0:An ArcGIS extension for calculating shoreline change[R]. Reston:U.S. Geological Survey, 2009.
Zhang H G, Guo Y X, Huang W G, et al. A remote sensing investigating of inning and silting in Hangzhou Bay since 1986[J]. Remote Sensing for Land and Resources, 2005, 17(2):50-54,81.doi: 10.6046/gtzyyg.2005.02.12.
doi: 10.6046/gtzyyg.2005.02.12
Sun C, Liu Y X, Li M C, et al. Spatiotemporal evolution of salt marsh and influential analysis of reclamation of Jiangsu middle coast in recent 25 years[J]. Journal of Natural Resources, 2015, 30(9):1486-1498.
The central people’s government of the PRC. Notice of the state council on strengthening the protection of coastal wetlands and strictly controlling reclamation[EB/OL].http://www.gov.cn/zhengce/content/2018-07/25/content_5309058.htm.
url: http://www.gov.cn/zhengce/content/2018-07/25/content_5309058.htm.