Topographical metrics for the nine study sites.

Describing the structural complexity of seabeds is of primary importance for a number of geomorphological, hydrodynamical and ecological issues. Aiming to bring a decisive insight on the long-term development of a unified view, the present study reports on a comparative multi-site analysis of high resolution topography surveys in rough nearshore environments. The nine study sites have been selected to cover a wide variety of topographical features, including rocky and coral seabeds. The topography data has been processed to separate roughness and bathymetry-related terrain features, allowing to perform a comprehensive spectral and statistical analysis of each site. A series of roughness metrics have been tested to identify the most relevant estimators of the bottom roughness at each site. The spectral analysis highlights the systematic presence of a self-affine range of variable extension and spectral slope. The standard deviation of the seabed elevation varies from 0.04 to 0.77 m. The statistical and multi-scale analysis performed on the whole set of roughness metrics allows to identify connection between metrics and therefore to propose a reduced set of relevant roughness estimators. A more general emphasis is placed on the need to properly define a unified framework when reconstructing roughness statistics and bathymetry from fine seabed topographical data.

探究海底结构复杂性，对诸多地貌学、流体动力学及生态学议题均具有核心重要意义。本研究旨在为统一认知的长期发展提供关键性见解，针对崎岖近岸环境中的高分辨率地形勘测开展多站点对比分析。本次研究选取的9个研究站点，覆盖了岩质海底、珊瑚质海底等多样地形特征。研究人员对地形数据进行处理，分离出粗糙度特征与测深（bathymetry）相关的地形特征，从而可对每个站点开展全面的频谱与统计分析。本研究测试了一系列粗糙度指标，以确定各站点底床粗糙度的最相关估计量。频谱分析结果显示，各站点均系统性存在可变延展范围与频谱斜率的自仿射区间。海底高程的标准差介于0.04至0.77米之间。通过对全部粗糙度指标开展统计与多尺度分析，本研究明确了各指标间的关联，并据此提出了精简后的有效粗糙度估计量集合。本研究进一步强调，在基于精细海底地形数据重构粗糙度统计量与测深地形时，需合理构建统一的分析框架。