Abstract: This study examined the spatial distribution of the continent coastline in northern China using remote sensing and GIS techniques, and calculated the fractal dimension of the coastline by box-counting method, with a time span from 2000 to 2012. Moreover, we analyzed the characteristics of spatial-temporal changes in the coastline's length and fractal dimension, the relationship between the length change and fractal dimension change, and the driving forces of coastline changes in northern China. During the research period, the coastline of the study area increased by 637.95 km, at an annual rate of 53.16 km. On the regional level, the most significant change of coastline length was observed in Tianjin and Hebei. Temporally, the northern China coastline extended faster after 2008. The most dramatic growth was found between 2010 and 2011, with an annual rate of 2.49%. The fractal dimension of the coastline in northern China was increasing during the research period, and the most dramatic increase occurred in the Bohai Rim. There is a strong positive linear relationship between the historical coastline length and fractal dimension, with the correlation coefficient being 0.9962. Through statistical analysis of a large number of local coastline changes, it can be found that the increase (or decrease) of local coastline length will, in most cases, lead to the increase (or decrease) of the whole coastline fractal dimension. Civil-coastal engineering construction was the most important factor driving the coastline change in northern China.

Key words: coastline, fractal dimension, remote sensing, spatial-temporal change, northern China