Freshwater lake inundation monitoring using Sentinel-1 SAR imagery in Eastern Uganda
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Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Annals of GIS
Abstract
In flood hazard assessment, little attention has been given to the seasonal observation of freshwater
inundation using Sentinel-1 Synthetic-Aperture Radar (SAR) images in the tropics. To assess these
spatial variations, this study examined the inundation magnitudes and reflectance of riparian flora in
the raining seasons (February-April and September-November) and dry-periods (May-August and
December-January). The inundation areas were determined using an object-oriented classification
algorithm, whilst the merits concerning the lake, riparian vegetation and shoreline were well-defined
using backscatter-coefficient values. Findings indicated that the SAR images are practical to monitor
inundation coverages and discern lake basin specific features such as highland areas, shoreline, water
and riparian-vegetation. Seasonally, inundated sizes were comparatively higher in February (902 sq.
km) and October (700 sq.km). Backscatter values of inundated parts varied from −16 dB to −19 dB,
whereas those of riparian vegetation were higher in the months of May and August. This study hence
displays a clear-cut correlation between riparian-vegetation, hydrology and climate variables.
Description
Keywords
Lake inundation, Sentinel-1, SAR images, Shoreline, Backscatter-coefficient
Citation
Bernard Barasa & Joshua Wanyama (2020) Freshwater lake inundation monitoring using Sentinel-1 SAR imagery in Eastern Uganda, Annals of GIS, 26:2, 191-200, DOI: 10.1080/19475683.2020.1743754