Environ Earth Sci (2016) 75:719 DOI 10.1007/s12665-016-5452-5 ORIGINAL ARTICLE Analysis of the characteristics and causes of coastline variation in the Bohai Rim (1980–2010) 1,2 1 1 Ning Xu • Zhiqiang Gao • Jicai Ning Received: 29 July 2015 / Accepted: 12 February 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract This paper retrieved categorical mainland Introduction coastline information in the Bohai Rim from 1980, 1990, 2000 and 2010 utilizing remote sensing and GIS tech- Coastal zone is a unique environment in which atmosphere, nologies and analyzed the characteristics and causes of the hydrosphere and lithosphere contact each other (Alesheikh spatial–temporal variation over the past 30 years. The et al. 2007; Sesli et al. 2009). Furthermore, the coastal zone results showed that during the research period, the length of is a difficult place to manage, involving a dynamic natural the coastline of the Bohai Rim increased continuously for a system that has been increasingly settled and pressurized total increase of 1071.3 km. The types of coastline changed by expanding socioeconomic systems (Turner 2000). For significantly. The amount of artificial coastlines increased coastal zone monitoring, coastline extraction in various continuously and dramatically from 20.4 % in 1980 to times is a fundamental work (Alesheikh et al. 2007). 72.2 % in 2010, while the length of the natural coastlines Coastline mapping and coastline change detection become decreased acutely. Areas that had coastlines that changed critical to coastal resource management, coastal environ- significantly were concentrated in Bohai Bay, the south and ment protection, sustainable coastal development, and west bank of Laizhou Bay and the north bank of Liaodong planning (Li et al. 2002). Bay. Due to the comprehensive effects of natural and There have been numerous studies on coastlines chan- anthropogenic factors, the coastline mainly expanded sea- ges. However, the coastline extracted by many processing ward. Coastal engineering construction were the leading methods (Lee and Jurkevich 1990; Ryu et al. 2002; Liu and factor in coastal evolution. Furthermore, the reclamation of Jwzek 2004; Kim et al. 2007) from the satellite images is aquaculture pond, salt field and harbor construction were the sea-land boundary that existed at the specific time of the top three construction activities. Additionally, the image acquisition, namely, the instantaneous coastline (Li driving force caused coastline change showed significant et al. 2002; Muslim and Foody 2008), rather than the real temporal heterogeneity. geographical definition of the coastline (Boak and Turner 2005; Ma et al. 2007; Xu et al. 2014). This instantaneous Keywords Spatial and temporal variation Á RS Á GIS Á coastline needs to be convert into a tide-coordinate coast- DSAS line (Li et al. 2002). This method has limited use for his- torical coastline determination, unless sufficient ground control and photogrammetric coverage is available (Gens & Zhiqiang Gao 2010). [email protected] Some scholars have carried out a great deal of research 1 on coastline change and related scientific issues in the Key Laboratory of Coastal Environmental Processes and Bohai Rim. Zhu and Xu (2012) analyzed the annual pro- Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, cesses of reclamation along the northwest coast of Bohai China Bay from 1974 to 2010. Sun et al. (2014) analyzed the 2 University of Chinese Academy of Sciences, Beijing 100049, coastline change and its driving forces in Bohai Bay from China 2000 to 2010. Xu et al. (2014) analyzed the characteristics 123 719 Page 2 of 11 Environ Earth Sci (2016) 75:719 of the spatial–temporal changes in the coastline’s length were downloaded freely from Earth Resources Observation and fractal dimension, relationship between the coastline and Science (EROS) Center website (http://glovis.usgs. length change and fractal dimension change, as well as gov/). All of which were rectified and projected using the driving forces of coastline changes in the Bohai Rim from Universal Transverse Mercator system in the world refer- 2000 to 2012. Overall, the researchers studied only partial ence system (WGS84) datum with geographical error regions of Bohai Rim or in short term, but not gave the within 0.5 pixels. Auxiliary data mainly included sea whole situation of coastline change in Bohai Rim in long charts, topographic maps, administrative maps and statis- term. tical yearbooks. In addition, a field investigation of the Therefore, in accordance with the Office of the State coastlines in the Bohai Rim was carried out to provide Oceanic Administration 908 Special (2005) definition, the significant support for the visual interpretation of the coastline was regarded as the line that traces the boundary coastline type. between land and sea during an average high spring tide. The objectives of this study were to analyze the characteristics of Extraction and classification of coastline the spatial–temporal variation of the coastline and its driving forces in the Bohai Rim. The visual interpretation method The coastlines are divided into mainland coastlines and was employed to retrieve the coastline types, and the baseline island coastlines, and this paper only studied the spatial– method was applied to analyze the coastline change at four temporal variation of the mainland coastlines in the Bohai time points (1980, 1990, 2000 and 2010). This research has a Rim. Currently, there is no uniform standard for the clas- reference value for scientific planning and rational utiliza- sification of coastlines (Gao et al. 2013). In previous tion of coastal resources in the Bohai Rim. studies (Sun et al. 2011; Gao et al. 2013; Hou et al. 2014), The Bohai Rim (Fig. 1) situated in north China, involves according to whether has not been utilized, the coastlines Liaoning Province, Hebei Province, Tianjin Municipality can be divided into natural coastline and artificial coastline. and Shandong Province in this paper. This Rim may be Then, natural coastline can be subdivided into bedrock described as a hotspot with respect to its large natural and coastline, sandy coastline, muddy coastline, biological artificial coastline changes. The coastline starts at the Yalu coastline and estuary coastline on the basis of composition River Estuary in Liaoning Province and ends at the junc- and spatial pattern. Artificial coastline can be subdivided tion of Shandong Province and Jiangsu Province, which is into aquaculture, salt field, cultivated field, construction, a range from 117°300E to 124°200E longitude and 35°50N harbor, revetment and seawall, transportation and groin on to 41°N latitude. This rim is becoming the third largest and the basis of functional use. most important economic zone in China after the Yangtze The following principles and interpretation standards River Delta and the Pearl River Delta. This rapidly were applied for determining the different types of coast- developing economic region is thriving at a quickened pace line (Zhu et al. 2001; Boak and Turner 2005; Ma et al. with a large population density and a high concentration of 2007; Xu et al. 2014). (1) For bedrock coast, the locations industries (Guo et al. 2009). Meanwhile, numerous major where ocean capes and upright cliffs directly contact with rivers in China flow into the Bohai Sea, including the seawaters were regarded as the coastline. For sandy coasts Yellow River, Haihe River, Luanhe River, Shuangtaizi that are generally flat, sandy sediments are carried by the River and Daliao River. Changes in natural conditions, spring tide and often deposited to form a ridge that is including (but not limited to) estuarine sedimentation and parallel to the shore; the position of this ridge was regarded erosion, and the influences of anthropogenic activities, as the location of the coastline. For muddy coasts that have such as coastal engineering, land reclamation, port con- been developed or encompass a relatively small area, the struction, and other activities, will inevitably cause con- coastline was regarded as the dividing line between tidal stant changes in coastlines and thereby affect the coastal flats and other surface features, such as vegetation line, environment (Xu et al. 2014). Thus, it needs to be studied seaward of coastal engineering, because at the height of at a high temporal frequency. spring tide, seawater cannot cross this dividing line. For muddy coasts without artificial development, the exposed land above the average high tide line during spring tides Methods and the tidal flat below the average high tide line during spring tides will typically be portrayed in different colors in Data remote sensing images; the dividing line between these two types of land was regarded as the coastline. (2) For coastal To detect coastline changes in the Bohai rim, a total of 62 estuaries: retain the harbor-like characteristics of large multi-temporal remote sensing data of Landsat MSS/TM/ estuaries; reflect the geomorphologic characteristics of ETM ? imageries captured in 1980, 1990, 2000 and 2010, sand spits, shoals, and lagoons of estuaries; manifest the 123 Environ Earth Sci (2016) 75:719 Page 3 of 11 719 Fig. 1 The coastline distribution in the Bohai Rim from 1980 to 2010 trumpet-shaped morphology of an estuary; treat asymmet- nicely depicts water–land interface and is very similar to ric canals based on the shapes of estuaries, assign the the true-color composite of earth’s surface. Moreover, it dividing line between estuaries to locations where rivers includes the bands that have low correlation coefficient, become narrow or the maximum curvature of capes occurs. and therefore, it contains higher information in comparison (3) Artificial coasts directly border seawater and generally to other color composites (Moore 2000; Alesheikh et al. feature regular land-sea demarcation lines, like ports and 2007). enclosed embankments; the seaward side of the artificial In light of the low spatial resolution of MSS images in coast was regarded as the artificial coastline.