Abstract
Abstract. We present a new classification scheme for muddy and sandy sediments on exposed intertidal flats, which is based on synthetic aperture radar (SAR) data, and use ALOS-2 (L-band), Radarsat-2 (C-band) and TerraSAR-X (X-band) fully polarimetric SAR imagery to demonstrate its effectiveness. Four test sites on the German North Sea coast were chosen, which represent typical surface compositions of different sediments, vegetation, and habitats, and of which a large amount of SAR is used for our analyses. Both Freeman-Durden and Cloude-Pottier polarimetric decomposition are utilized, and an additional descriptor called Double-Bounce Eigenvalue Relative Difference (DERD) is introduced into the feature sets instead of the original polarimetric intensity channels. The classification is conducted following Random Forest theory, and the results are verified using ground truth data from field campaigns and an existing classification based on optical imagery. In addition, the use of Kennaugh elements for classification purposes is demonstrated using both fully and dual-polarization multi-frequency and multi-temporal SAR data. Our results show that the proposed classification scheme can be applied for the discrimination of muddy and sandy sediments using L-, C-, and X-band SAR images, while SAR imagery acquired at short wavelengths (C- and X-band) can also be used to detect more detailed features such as bivalve beds on intertidal flats.
Highlights
Intertidal flats are an intermediate area between the land and sea and fall dry once during every tidal cycle (Gade and Melchionna 2016, Geng et al, 2016)
Synthetic Aperture Radar (SAR) sensors have the unique advantage of combining high spatial resolution with the independence of sunlight and weather conditions; SAR sensors are already regarded as a useful tool for the monitoring of the German Wadden Sea (Müller et al, 2016), which is a UNESCO World Natural Heritage since 2009
In the present study we found that the FCD-Random Forest (RF) algorithm is able to detect oyster beds in the Wadden Sea, which led us to additional analyses of the scattering mechanism for sediments, tidal channels, and oyster beds using Kennaugh elements
Summary
Intertidal flats are an intermediate area between the land and sea and fall dry once during every tidal cycle (Gade and Melchionna 2016, Geng et al, 2016). Traditional surveying and mapping methods face large constrains, because of their low time-efficiency and high manpower cost. This is when remote sensing techniques come into play. The dependence on sunlight and weather conditions always limits the usage of optical remote sensing sensors. Synthetic Aperture Radar (SAR) sensors have the unique advantage of combining high spatial resolution with the independence of sunlight and weather conditions; SAR sensors are already regarded as a useful tool for the monitoring of the German Wadden Sea (Müller et al, 2016), which is a UNESCO World Natural Heritage since 2009
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
