Shallow Water Empirical Remote Sensing Bathymetry Using the Blue/Green and Red Spectrum Regions
Gar Al-Nabi Ibrahim Mohamed *
Department of Hydrographic Surveying, Faculty of Maritime Studies, King Abdulaziz University, Kingdom of Saudi Arabia.
*Author to whom correspondence should be addressed.
Abstract
An atmospherically corrected Sentinel-2 image and a 1/25000 scale nautical chart were used to investigate the performance of the electromagnetic spectrum blue/green and red regions in bathymetric data retrieval. The imaging optical empirical remote sensing bathymetry, using Stumpf (2003) reflectance model was adopted in this investigation. In clean water depth (3.1-7.3) meters both spectrum regions can be used to retrieve bathymetric data with an accuracy of ± (0.82-1.10) m. The optimum electromagnetic spectrum regions in this depth range were the blue/green spectrum range (0.457-0.523 μm) and the red range (0.773-0.793 μm). For depth range (2.1-15.5) m, the blue/green spectrum region (0.457-0.523 μm) produced better results than those of the red region. The clean water derived bathymetric data quality decreases with the increase of water depth in general and with the red spectrum region in particular. The blue/green spectrum region (0.457-0.523 μm) and the red spectrum region (0.773-0.793 μm) correlation coefficient values can be adopted as a measure of the water turbidity, using the characteristic of the water depth strong correlation in turbid water.
Keywords: Electromagnetic spectrum, blue/green spectrum region, red spectrum region, correlation coefficient, root mean square error, absolute mean error