南海珊瑚礁高分辨率遥感地貌分类体系研究

Development of a geomorphic classification scheme for coral reefs in the South China Sea based on high-resolution satellite images

珊瑚礁遥感地貌分类体系在珊瑚礁遥感地貌制图中具有重要的指导作用。目前,珊瑚礁遥感地貌分类体系仍存在构建标准不统一、部分重要地貌类型不突出以及涵盖地貌类型不完备等问题,影响了珊瑚礁遥感地貌制图应用于珊瑚礁科学和管理。本文采用中国南海46个珊瑚礁(环礁、台礁)的高分辨率遥感影像(WorldView-2、Quickbird),并结合西沙群岛15个岛礁的地貌实地调查数据进行南海高分辨率遥感地貌分类体系的构建研究。以各地貌类型所处礁体位置、动力特征、出露程度和沉积类型为划分标准,将相似尺度和重要性相当的地貌类型归为同等级别,共构建了3级19类南海珊瑚礁遥感地貌分类体系。该分类体系划分标准统一、地貌类型数量最多且完备,新命名了内礁坪生物稀疏带、内礁坪生物丛生带,补充了水下礁脊、潮间带浅滩、浅水礁塘等地貌类型,便于直观理解和推断不同尺度的海洋生态相互作用及重要性。同时,其多等级多尺度性适用于分辨率由低到高的南海珊瑚礁遥感地貌制图,有助于珊瑚礁态势演变分析、管理和保护,为维护国家海洋权益作出应有的贡献。

Coral reef geomorphic classification scheme plays an important role in coral reef geomorphic mapping based on remote sensing images. At present, there are various problems in the coral reef geomorphic classification schemes for remote sensing, such as inconsistent construction standards, unreasonable levels of some important geomorphic types, and incomplete geomorphic type coverage, which limit the application of geomorphic mapping for coral reef science and management. This articel advocates a systematic and hierarchical geomorphic classification scheme for reefs in the South China Sea for remote sensing, which concludes three levels and 19 classes from the sea to the lagoon or island. It is constructed based on high-resolution satellite images(WorldView-2, Quickbird) of 46 reefs(atolls, table reefs) and field survey data of 15 reefs in the Xisha Islands. Geomorphic types are derived and described according to the criteria of reef location, hydrodynamic characteristics, exposure degree and sediments. Geomorphic types are placed at the same level when they possess similar scale and importance. Cay and island are placed in the first level to show their importance. The scheme has consistent standardization, the highest hierarchical structure, and the largest number of geomorphic types. In the scheme, biotic sparse zone of the inner reef flat, biotic dense zone of the inner reef flat are named;submerged reef ridge, intertidal sand zone, and shallow reef pond are supplemented. The classification scheme facilitates the intuitive understanding and inference of the processes and importance of marine ecological interaction across different scales. This hierarchical geomorphic classification scheme with multi-scale characteristic is applicable to the coral reef geomorphic mapping from low-resolution to high-resolution satellite images, contributing to the change analysis, management, and protection of China’s coral reefs in the South China Sea.