| Dongsha soual is an important geomorphic unit in the radiant sand ridges in the southern Yellow Sea.Studying the dynamic changes of the Dongsha soual landform can provide important scientific basic data for Dongsha soual land,marine resources development,shipping and inscription.Based on the remote sensing study of the radiation sandy ridge group in the South Yellow Sea and Dongsha soual as the research carrier,based on the long-period Dongsha soual low tide level remote sensing image,using remote sensing and GIS,And the area,the minimum bounding rectangle center of mass,the trend of whole and subdivision of subdivision line as well as the change of tidal channel,and then the ebb and flow situation and stability of various parts of Dongsha soual are inferred.The findings are as follows:(1)The trend of Dongsha soual waterfront has a drastic trend in 43 a,of which the east coast is relatively more intense and the west coast is relatively flat.(2)Dongsha soual The main beach area has shrunk from55457.57 hectares in 1973 to 40691.83 hectares in 2016,shrinking by 26.63% due to lack of natural resources and human activities such as reclamation and breeding.(3)The general direction of Dongsha soual during the period of 43 a is north-northeast.The overall movement of Dongsha soual is 3.1713 km to the Taipingzha and the velocity is 0.0991 km / a.Dongsha soual movement can be roughly divided into five stages: from 1973 to 1979,Dongsha soual made a relatively gentle movement to the north with a travel distance of 0.8494 km and a speed of 0.2831 km / a;from 1983 to1989,Dongsha soual made a northward move A relatively high-speed movement with a moving distance of 2.9630 km and a speed of 0.5926 km / a.From 1991 to 1999,Dongsha soual moved northeastward with a moving distance of 1.5088 km and a speed of 0.2156 km / a.From 2000 to 2009,Dongsha soual moves slowly to the south with a travel distance of 1.4402 km and a speed of 0.1600 km / a.From 2011 to 2016,Dongsha soual made a relatively high-speed movement to the south-southeast with a travel distance of 1.6718 km and a speed of 0.4180 km / a.(4)The phenomenon of high-speed movement of Dongsha soual's smallest circumscribed rectangular centroid mostly appears after tropical cyclone transit,and the response of centroid to tropical cyclone tends to be more and more strong.(5)On the whole,the change of Dongsha soual ridge line shows the relatively stable northern part and the intense southern part.(6)The erosion in the west coast of Dongsha soual,especially in the southern part of the West Bank,caused a swirling counterclockwise deflection in Dongsha soual's NW-SE ridgeline.As for the phase of Dongsha soual ridge line deflection,it can be divided into stable deflection(1973-1979),repeated swinging(1983-1989),continuous deflection(1991-1999),complex and changeable(2000 Year-2009)and fast deflection(2011-2016)five stages.(7)The north and south sections of the Dongsha soual ridge line swung eastward to the east and the middle section swung westward to the west.In terms of average swing speed,the intersection of E>intersection D> intersection A> intersection B> intersection C.In terms of swing intensity,the intersection of E> intersection D> intersection C> intersection B>intersection A.(8)According to the spatial interpolation result of the swinging intensity of sand ridge,it can be clearly seen that the intensity of the swing of Dongsha soual sand ridge line increases from north to south. |
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