Remote Sensing Method Research In The Evolution Of The Scouring And Silting In Tidal Flats

The tidal flat is important land reserve resource in coastal areas as the population continues to increase and the cultivated land resources in coastal areas decrease sharply. It is very important to master the erosion and siltation dynamic of the tidal flat. Remote sensing can judge erosion and siltation situation of the tidal flat accurately, and it is important for the reasonable development of land resources. This paper takes part of silt-muddy tidal flats in Dafeng and Dongtai,Jiangsu province for study area, uses the tidal flat slope surface and the tidal levels to get the elevation characteristic lines at a certain time, and summarizes the main characteristics of this characteristic lines to extract the characteristic lines in other phase image. The following are the main contents and results of this study:(1) Tidal flat slope surface is acquired from the actual measurement elevation in the year2006. The average high tide characteristic line is extracted combined with tide levels.(2) The average high tide characteristic line in the year2006is imported into the image of this year which is after the tasseled cap transformation. The average humidities of the average high tide characteristic line and the coverage of the image are extracted. A difference of16, which is for reference to extract the average high tide characteristic lines in other phase image, is found between the two indexes.(3) The average high tide characteristic lines in the year1992,1999and2008are extracted. The tidal flats near the average high tide characteristic lines from the year1992to2008presents silting long state. An average distance of3143meters for which the characteristic lines go on to the sea is calculated.(4) There isn’t obvious ground object feature near the low tide characteristic line. This paper defines the average low tide characteristic line as identification mark, extracts the average low tide characteristic lines of the year2006,2008and2009by using tidal levels and tidal flat slope surface. The tidal flats near the average low tide characteristic lines from the year2006to2009are scour state. An average distance of223meters for which the average low tide characteristic lines go on to the land is caculated.(5) The evolution of the tidal flats shows that the upside is alluvial and the underpart is erosive.