1995—2017年福建省海岸线时空变化分析

利用遥感影像和GIS技术相结合获取福建省1995、2001、2010、2017年共4期海岸线的时空分布情况,并结合网格法计算各时期海岸线的分形维数,结合获取数据分析海岸线的时空变化特征、海岸线长度变化与分形维数变化之间的关系以及影响海岸线变化的原因。结果表明:1995—2017年福建省海岸线长度呈持续增加趋势,共增加388.99 km。从时间方面来看,2010年之后海岸线长度进入快速增长时期,其中2010—2017年是海岸线长度变化最显著的时期;从区域上来看,以宁德和莆田岸线变化最强烈,其他地市相对较稳定。1995—2017年研究区海岸线分形维数总体呈现先增加后减小趋势,其中宁德、福州、泉州分形维数变化比其他地市要复杂。研究区历史海岸线长度变化与分形维数变化之间存在着一定的相关关系,对各地市海岸线长度变化与分形维数变化统计分析表明,总体来看局部海岸线长度的增加或减小会导致整体海岸线分形维数增大或减小,且呈正比例变化。对1995—2017年研究区各时段海岸线变化对应的面积汇总情况来看,人类活动是影响研究区海岸线变化的主要原因,与人类活动相比,自然变化如河口淤积与侵蚀等对海岸线影响较小。

Spatial-temporal changes of coastline in Fujian Province from 1995 to 2017

This study examined the coastline changes of Fujian Province using remote sensing and GIS techniques. The fractal dimension of the coastline is calculated using 4 year data from 1995, 2001, 2010 and 2017 by box counting method. At the same time the characteristics of spatial temporal changes of the coastline, the relationship between the changes of coastline length and fractal dimension along with the causes of coastline changes are analyzed. The results show that the coastline increased by a total of 388.99 km in 1995-2017. It entered a fast increment period after 2010. The length changed dramatically along the coasts of Ningde and Putian compared with other areas where coastlines changed less. The fractal dimensions of the coastline increased and then decreased in the study period and the changes were more complicated in areas of Ningde, Fuzhou and Quanzhou. A linear relationship existed in a certain extent between the historical coastline length and fractal dimensions. Statistical analysis on the changes of coastline lengths and fractal dimensions demonstrates that the increase (or decrease) of local coastline length, in most cases, leaded to the positive increase (or decrease) of whole coastline fractal dimensions. Compared to the natural factors such as estuarine depositions and shoreline erosions, civil-coastal engineering construction was a more important factor varying the coastlines in Fujian province.