Retrieval of nearshore bathymetry in the Gulf of Chania, NW Crete, Greece, from WorldWiew-2 Multispectral Imagery

摘要

Shallow water bathymetry is recognized as one of the most fundamental topics in environmental studies, seabed morphology research and management of the coastal zone. The detailed mapping as well as the long-term monitoring of the changes in shallow marine relief is important for the successful completion of coastal construction and environmental projects. In recent years, optical satellite imagery is proving to be a useful tool to determine coastal bathymetry, as it provides a time- and cost- effective solution to water depths estimation. In this paper, the two most popular and successful approaches for bathymetry retrieval, the Lyzenga (1985) linear bathymetry model and the Stumpf et al. (2003) ratio method, have been applied to Worldview-2 satellite imagery, in order to derive the more accurate bathymetric model for the shallow-water region of the Chania Gulf, located in NW Crete Island, Greece. This area is sea-grass free and is dominated by sandy substrate with a few rocky outcrops. The models are implemented over the total study area -no separation in subareas according to the bottom type. The results are compared with echo sounding ground truth depth data. The outcomes of the statistical analysis indicate that the linear model provides increased accuracy than the ratio one over the sandy bottom. On the contrary, in those parts covered by rocky bottoms, none of the two models provided satisfactory results.