| The tidal flats in Jiangsu Province are flat and wide,and the reserve land resources in the intertidal zone are sufficient,and the development and utilization prospects are broad.In recent years,under the influence of the regulation policy of reclamation,the coastal tidal flat reclamation has been significantly enhanced.The coastline has changed frequently due to the combination of natural factors and human factors.Therefore,the dynamic monitoring of coastline changes is of great significance for the rational development and scientific management of coastal zones.The traditional method of measuring the coastline in the field is time-consuming and labor-intensive,and the data is updated slowly,which can not meet the actual needs of the coastal management department.The existing method of estimating the coastline by means of remote sensing is not common in the silt muddy tidal flat area of Jiangsu.Based on this,this paper proposes a new method for estimating the coastline remote sensing based on the different topographic features of the tidal flat in Jiangsu.In the north bank of the Liangduo River,the shoreline is straight,the number of tidal creeks is small and the width is narrow.Firstly,according to the tidal range relationship between the multi-temporal remote sensing waterlines,the shape of the bank shoal was automatically discriminated,and then using different functions for profile fitting.A new method of coastline remote sensing estimation based on section shape adaptation was constructed.In the south bank of Liangduo River,the tidal beach shoreline were tortuous,and the tidal creek was complex.Firstly,the tidal level was assigned to the multi-temporal waterside line data,and then the irregularity was constructed.The triangular network TIN was used to generate the tidal flat DEM model.Based on the DEM,the tidal flat section was intercepted and the function was fitted.A new method of coastline estimation based on DEM-based section shape fitting was constructed.Through the monitoring of the long-term coastline and low tide lines in 1988,1993,2002,2006 and 2018,the dynamic changes of the intertidal zone in Jiangsu Province under the regulation policy of reclamation and reclamation are analyzed.The main research contents and conclusions of this paper are as follows:(1)When the coastline is estimated by the profile morphology adaptation method,the absolute error of the estimated distance of the coastline of the concave erosion section is-30.51m?16.58m,the gentle section of the slope is-354.33m?-91.31m,and the upper convex section is 0(-914.29?-634.4)m,the error is reduced by about 82.4%compared with the average slope method.From the error results calculated from different numbers of waterlines,the ideal accuracy can be achieved by using five waterlines to calculate the coastline.(2)When using the DEM-based profile shape fitting method to estimate the coastline,the calculated artificial shoreline distance error is between 45.73m and 39.29m,and the estimated natural shoreline distance is measured in the range of 1093.55m?4117.20m.(3)According to the remote sensing monitoring results of the land bank in Jiangsu Province,it was found that during the period of 1988-2018,due to the impact of the regulation policy of reclamation,the length of artificial coastline in the province increased significantly,and the natural coastline gradually shrank and shattered.The province's scouring shoreline is mainly concentrated in the port section of Guanhe River to Sheyang River and near the shore of Haozhi Port.The other shore sections are propelled to the sea as a whole,and the Biandan River to Sheyang River is a transitional section from erosion to siltation.Due to the siltation of the beach,the restoration of natural vegetation and the impact of the cofferdam development project,the province's land area increased by 78,800 hectares.(4)From the change of intertidal zone,between 1988 and 2018,from the north of the Sheyang River to the Xiuzhen River,the intertidal zone is relatively narrow,and the whole is characterized by undulating fluctuations,from Sheyang estuary to the Yaosha area,the intertidal zone width is decreasing.The total area of the intertidal zone in the province has decreased by 1126.32km~2,which is greater than the increase of 858.35km~2 in the land area.This indicates that the upper tidal zone is silting up and reclaiming while the subtidal zone begins to erode.(5)Judging from the change of tidal flat slope,the largest slope area in the province is located in the Longwang Estuary and Zhendongzha section,the average annual slope is 5.86‰ and 5.64‰.The average slope from the Sheyang River to the Haozhi port of radial sand ridges is small and does not exceed 1.4‰.(6)From the results of typical shore monitoring,the tidal flat from the Guanhe River to Zhongshan River section is narrow,and the coastline generally shows the characteristics of overall erosion and retreat;the shore section from Xinyang Port to Doulong Port is mainly driven by natural siltation to the sea;The shore section of Dafeng Port is mainly driven by artificial construction and advancing toward the sea;the intertidal zone width of the Yaosha shore is the largest,and the tidal ditch is developed and complicated,and the erosion and silt length alternate. |
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