Study On Human Interference And Fractal Dimensions Of Different Shoreline Types

As a boundary area between the land and the ocean,the coastal zone frequently exchanges materials and flows energy.With the development of the coastal economy,the relationship between man and land has become increasingly tense,and the degree of human intervention in coastal areas has been continuously improved.The land use patterns in coastal areas has gradually changed from natural landscape to artificial landscape.At the same time,the morphological characteristics of the shoreline have also and the morphological characteristics of coastline have also changed significantly.However this change has led to a sharp increase in the intensity of human disturbance in coastal areas,affecting the ecological environment of coastal areas.This paper takes the eastern coastal zone of Zhejiang Province as the research area,involving six coastal cities including Jiaxing City,Hangzhou City,Shaoxing City,Ningbo City,Taizhou City and Wenzhou City.Using RS and GIS technology,the dynamic changes of coastline morphological characteristics and fractal dimension under different coastline types in the study area were analyzed,the dynamic changes of coastline morphological characteristics and fractal dimension under different coastline types in the study area were analyzed.The correlation between fractal dimension and human disturbance degree was discussed in depth.The results show:(1)Under the intervention of human activities,the length of the coastline in Zhejiang Province showed a gradual downward trend from 1995 to 2010,with an overall decrease of 73.86 km.Among them,the natural shoreline length declined significantly in 15 years,from 792.75 km in 1995 to 262.61 km in 2010.The length of artificial shoreline shows an increasing trend year by year,with an increase of 420.48 km in 15 years;In terms of fractal dimension,the natural shoreline has a fractal dimension higher than the artificial shoreline due to the tortuosity of the shoreline itself and the protection of the natural shoreline by human beings in the later period of humanity.The fractal dimension of the natural shoreline is between 1.0349 and 1.1558,and the fractal dimension of the artificial shoreline is between 1.0008 and 1.0981.(2)With the economic development needs of coastal cities,a large number of tidal flats near the coastline have been developed,and the land use pattern has changed from agricultural land to construction land,while the proportion of construction land has increased,which makes the intensity of human interference in the study area increase year by year.Through quantitative analysis,it is found that the intensity of human disturbance is between 3 and 5 in the areas dominated by artificial shoreline,while the intensity of human disturbance is weaker in the areas dominated by natural shoreline,ranging from 2 to 3.In the specific spatial distribution,the maximum interference intensity of artificial coastline appears in areas with abundant tidal flat resources.The large-scale exploitation of beach resources makes the human interference intensity of this type of sea areas appear high.The minimum interference intensity of artificial shoreline occurs in the southern part of Zhejiang Province,where the terrain is complex and the development is difficult,so there is a low interference intensity area.The maximum intensity of natural shoreline interference occurs mostly in concave bedrock and silt coasts.These areas are easier to be developed by virtue of geographic advantages,so the value of disturbance intensity is larger.The lower intensity of natural shoreline disturbance occurs in the bedrock coast of southern Zhejiang Province,where human activities are less,so the intensity of natural shoreline disturbance is smaller.(3)On the whole,there is a negative correlation between human interference and fractal dimension,and the correlation is good,that is,the larger the fractal dimension,the smaller the human interference.Specific analysis shows that the correlation betweenartificial shoreline interference and fractal dimension is higher than that of natural shoreline.This is because human activities directly affect the tortuosity of artificial shoreline,while natural shoreline has a slightly lower correlation than artificial shoreline due to its complexity and ecological restoration in recent years.In terms of model,in the artificial shoreline,the best fitting effect is the one-dimensional quadratic model.while the exponential model has the worst fitting effect.In the natural shoreline,the exponential model has the best fitting effect,while the power model has the worst fitting effect.In terms of accuracy,the average accuracy of both natural and artificial shorelines after verification is over 90%,and the accuracy is higher.