近100a来浙江大陆海岸线时空变化特征

Continental shoreline change in Zhejiang duringthe last one hundred years

收集7个时期的历史图件或卫星遥感影像,运用RS和GIS技术,进行信息提取和实测岸线数据验证,获取各时期浙江大陆海岸线矢量,统计分析结果显示:(1)浙江大陆海岸线总体上表现为海岸线位置外推加快,平直的人工岸线不断取代曲折的自然岸线,部分近岸岛屿并入大陆,海岸线长度明显缩短,百年来人工岸线所占比例由48.01%上升至67.46%。(2)人工岸线和围垦面积变化规律总体呈现出3个明显阶段:1913—1970年自耕农时代高滩围垦阶段,人工岸线长度增加288.78km,围垦面积仅增593.35km2;1970—1995年集体农业时代联围堵港阶段,围垦面积快速增加,人工岸线长度反而减少;1995—2014年工业与城镇化建设围垦阶段,人工岸线长度增加116.66km,而围垦面积剧增1 053.00km2。(3)河口区大陆海岸线全线平移外推,海岸线长度则有增有减,1913年以来浙江主要河口区围填海面积达1 914.85km2,占全省围填海面积的76.79%。(4)海湾区大陆海岸线变化以截弯取直为特点,岸线总长度持续减少,百年来三大港湾围填海面积达429.32km2,占全省的17.22%。

Combining the remote sensing images and regular data,the continental shorelines at seven periods in Zhejiang were depicted by using the data during the last 100 years.In those seven periods,continental shoreline types and sea reclamation area were calculated and the results are as follows：（1）The spatial pattern of the sea reclamation and way varied from time to time and the proportion of artificial shoreline has been risen from 48.01% to 67.46% during the last 100 years.（2）The relation between the increment of artificial shoreline and the area of reclamation presented three obvious stages from 1913 to 2014：The first stage is that the largest increment of artificial shoreline between 1913-1970 corresponded to the smallest reclamation area change,which meant that people were priority to individual farming during that time.The second stage is that the reclamation area had began to increase rapidly between 1970-1995 while the artificial shoreline reduced,which represented at this time it was collectivized agricultural era.And the third is that the increment of artificial shoreline is relatively small,however,reclamation area increases enormously,which shows that we are now in the stage of both industry and urban land use.（3）The estuarine coastline has been being translated to the sea and the coastline length has increased or decreased.Since 1913,the main estuary reclamation area is about 1 914.85km^2,and this is around 76.79%in Zhejiang Province.（4）The major changes in the gulf coast was the blockage of the harbor and the total length of shoreline were being continued to reduce in the last 100 years.Since 1913,these three harbors＇ reclamation area is 429.32km^2,and it is about 17.22%in Zhejiang Province.