Investigating the use of the dual-polarized and large incident angle of SAR data for mapping the fluvial and aeolian deposits
Open Access
- 1 December 2017
- journal article
- Published by Taylor & Francis Ltd in NRIAG Journal of Astronomy and Geophysics
- Vol. 6 (2), 349-360
- https://doi.org/10.1016/j.nrjag.2017.10.005
Abstract
Mapping the spatial distributions of the fluvial deposits in terms of particles size as well as imaging the near-surface features along the non-vegetated aeolian sand-sheets, provides valuable geological information. Thus this work aims at investigating the contribution of the dual-polarization SAR data in classifying and mapping the surface sediments as well as investigating the effect of the radar incident-angle on improving the images of the hidden features under the desert sand cover. For mapping the fluvial deposits, the covariance matrix ([C2]) using four dual-polarized ALOS/PALSAR-1 scenes cover the Wadi El Matulla, East Qena, Egypt were generated. This [C2] matrix was used to generate a supervised classification map with three main classes (gravel, gravel/sand and sand). The polarimetric scattering response, spectral reflectance and temperatures brightness of these 3 classes were extracted. However for the aeolian deposits investigation, two Radarsat-1 and three full-polarimetric ALOS/PALSAR-1 images, which cover the northwestern sandy part of Sinai, Egypt were calibrated, filtered, geocoded and ingested in a GIS database to image the near-surface features. The fluvial mapping results show that the values of the radar backscattered coefficient (Ï°) and the degree of randomness of the obtained three classes are increasing respectively by increasing their grain size. Moreover, the large incident angle (θiâ¯=â¯39.7) of the Radarsat-1 image has revealed a meandering buried stream under the sand sheet of the northwestern part of Sinai. Such buried stream does not appear in the other optical, SRTM and SAR dataset. The main reason is the enhanced contrast between the low backscattered return from the revealed meandering stream and the surroundings as a result of the increased backscattering intensity, which is related to the relatively large incident angle along the undulated surface of the study area. All archaeological observations support the existence of paleo-fresh water lagoon at the northwestern corner of the study area, which might have been the discharge lagoon of the revealed hidden stream. Keywords: Dual-polarized SAR data, Mapping fluvial deposits, Incident angle of SAR signals, Imaging near-surface features, Aeolian sand coveKeywords
This publication has 28 references indexed in Scilit:
- A study of land cover classification using polarimetric SAR parametersInternational Journal of Remote Sensing, 2007
- Conservative Polarimetric Scatterers and Their Role in Incorrect Extensions of the Cameron DecompositionIEEE Transactions on Geoscience and Remote Sensing, 2006
- Late-Season Rural Land-Cover Estimation With Polarimetric-SAR Intensity Pixel Blocks and$sigma$-Tree-Structured Near-Neighbor ClassifiersIEEE Transactions on Geoscience and Remote Sensing, 2006
- Unsupervised classification of multifrequency and fully polarimetric SAR images based on the H/A/Alpha-Wishart classifierIEEE Transactions on Geoscience and Remote Sensing, 2001
- A three-component scattering model for polarimetric SAR dataIEEE Transactions on Geoscience and Remote Sensing, 1998
- An entropy based classification scheme for land applications of polarimetric SARIEEE Transactions on Geoscience and Remote Sensing, 1997
- Classification of multifrequency polarimetric SAR imagery using a dynamic learning neural networkIEEE Transactions on Geoscience and Remote Sensing, 1996
- A review of target decomposition theorems in radar polarimetryIEEE Transactions on Geoscience and Remote Sensing, 1996
- Microwave Penetration and Attenuation in Desert Soil: A Field Experiment with the Shuttle Imaging RadarIEEE Transactions on Geoscience and Remote Sensing, 1986
- Spaceborne Radar Subsurface Imaging in Hyperarid RegionsIEEE Transactions on Geoscience and Remote Sensing, 1984