深圳市1978年至2005年海岸线的动态演变分析

海岸带是目前科学研究的热点区域，海岸线动态演变是其重要研究内容之一。本文以快速城市化地区深圳市为研究区域，以1978年、1986年、1995年、1999年和2005年等5期Landsat MSS/TM/ETM+影像为数据源，利用阈值结合NDVI指数法提取各期海岸线，系统分析海岸线时空动态演变特征，并初步探讨其驱动因素。研究结果表明：①基于该方法的各类型海岸线遥感影像提取精度较高，精度均在70%以上；②研究时段内，深圳海岸线长度呈现先增长后缩短的变化趋势，并且西海岸岸线变化相比东海岸更为显著；③人为造陆是海岸线变化的主要驱动因素，其作用方式包括滩涂围垦和填海造地；④地貌环境由海拔、坡度以及岩性等地貌因子共同作用形成的地形条件和海岸物质组成，通过制约人类活动强度和方式，影响海岸线动态变化。

Research on Dynamic Changes of Coastline in Shenzhen City based on Landsat Image

Coastal zone has become a hot spot of research in recent years and research on dynamic changes of coastline has played an increasingly important role in it. This paper takes the rapid urbanization area of Shenzhen city as the study area, since Shenzhen has become one of the most important cities in china after the reform and opening-up. Its coastline has greatly changed because of large amount of constructions in the coastal zone. With the aid of technologies, including remote sensing and geographic information system(GIS) software such as ERDAS8.7 and ArcGIS9.2, we depict the coastlines of Shenzhen by using five Landsat MSS/TM/ETM+ images of the year of 1978, 1986, 1995, 1999 and 2005 with the method which combines threshold and NDVI index. In addition, we also systematically analyze the characteristics of coastline changes during the study period and conduct initial discussions on its driving factors. The results show that: during the study period, based on the method combining threshold and NDVI index, the average accuracy of depicting each kind of coastline is above 70%, which is acceptable in this research. In addition, the length of coastline increases from 1978 to 1995 at first and reduces since 1995, and the extent of changes on the west coast is much more significant than that on the east coast. Meanwhile, as the main driving factor, human activities, including beach reclamation and land reclamation, have greatly aggravated the changes of coastline, and the intensity of human activities on the west coast is also much more noticeable than that on the east coast. Besides human activities, geomorphologic environment also has considerable impact on the changes of coastline. Geomorphologic environment is composed of factors such as altitude, slope and lithology. Through affecting the intensity and means of human activities, geomorphology environment also affects the changes of coastline. Thus the driving factors of changes of coastline are constituted of human activities and geomorphology environment. In the end, we discuss the expectation of relative research in the future. It is necessary to focus on the condition of water kinetics. As the changes of the coastline, the shape of the landform also changes, which may result in the deposition of mud and sand in the bayou and influences the normal ship transport. In addition, the change of coastal shapes may also intensify the harmful pollutions.