Response of Multi-Incidence Angle Polarimetric RADARSAT-2 Data to Herbaceous Vegetation Features in the Lower Paraná River Floodplain, Argentina
| Autor: | Francisco Grings, Natalia Soledad Morandeira, Patricia Kandus, Frank Ahern, M. Barber, Brian Brisco |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Marsh
Paraná River Delta 010504 meteorology & atmospheric sciences Floodplain incidence angle Ludwigia peruviana Emergent plant Science 0211 other engineering and technologies Wetland 02 engineering and technology double-bounce scatter Schoenoplectus californicus flooded marshes 01 natural sciences active microwave C-band 021101 geological & geomatics engineering 0105 earth and related environmental sciences polarimetry geography Biomass (ecology) geography.geographical_feature_category biology co-polarized phase difference Vegetation biology.organism_classification wetland macrophytes General Earth and Planetary Sciences Environmental science Physical geography |
| Zdroj: | Remote Sensing Volume 13 Issue 13 Remote Sensing, Vol 13, Iss 2518, p 2518 (2021) |
| ISSN: | 2072-4292 |
| DOI: | 10.3390/rs13132518 |
| Popis: | Wetland ecosystems play a key role in hydrological and biogeochemical cycles. In emergent vegetation targets, the occurrence of double-bounce scatter is indicative of the presence of water and can be valuable for hydrological monitoring. Double-bounce scatter would lead to an increase of σ0HH over σ0VV and a non-zero co-polarized phase difference (CPD). In the Lower Paraná River floodplain, a total of 11 full polarimetric RADARSAT-2 scenes from a wide range of incidence angles were acquired during a month. Flooded targets dominated by two herbaceous species were sampled: Schoenoplectus californicus (four sites, Bulrush marshes) and Ludwigia peruviana (three sites, Broadleaf marshes). As a general trend, σ0HH was higher than σ0VV, especially at the steeper incidence angles. By modeling CPD with maximum likelihood estimations, we found results consistent with double-bounce scatter in two Ludwigia plots, at certain scene incidence angles. Incidence angle accounted for most of the variation on σ0HH, whereas emergent green biomass was the main feature influencing σ0HV. Multivariate models explaining backscattering variation included the incidence angle and at least two of these variables: emergent plant height, stem diameter, number of green stems, and emergent green biomass. This study provides an example of using CPD to decide on the contribution of double-bounce scatter and highlights the influence of vegetation biomass on radar response. Even with the presence of water below vegetation, the contribution of double-bounce scatter to C-band backscattering depends on scene incidence angles and may be negligible in dense herbaceous targets. |
| Databáze: | OpenAIRE |
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