Emerging Applications of Interferometric Synthetic Aperture Radar (InSAR) in Geomorphology and Hydrology

Abstract

Interferometric synthetic aperture radar (InSAR) is a powerful geodetic tool used to construct digital elevation models of the earth's topography and to image centimeter-scale displacements associated with crustal deformation and the flow of ice sheets. The past decade has seen significant improvements in our understanding of earthquakes, volcanoes, and glaciers as a direct result of this technology. Geomorphology and hydrology can also benefit from InSAR. A small but growing body of work shows that it is possible to interferometrically measure centimeter-scale motions associated with unstable slopes, land subsidence, fluctuating soil moisture and water levels, and deforming river-ice cover. Maps of interferometric correlation provide information about the structure of snow and reveal areas disturbed by erosion, sedimentation, flooding, snowfall, and aufeis growth. At present, such techniques are underdeveloped and largely overlooked by the geographic and radar communities. This article reviews these emerging geomorphic and hydrologic applications of InSAR and presents a first demonstration of motion detection for river ice.

Relationships between landscape morphology, climate and surface erosion in northern Peru at 5°S latitude

“…These images have a ground resolution of 30 m. They record the phase (time delay) and amplitude (energy intensity) of microwave echoes returned from Earth's surface. We select SAR intensity difference data because SAR amplitudes (energy intensities) are sensitive to roughness patterns of topographies (Smith 2002). This implies that any large-scale modifications in the surface roughness caused by e.g., gullying, dissecting, and landsliding are expected to yield a distinct pattern of intensity change that we intend to detect here.…”

The application of satellite differential SAR interferometry-derived ground displacements in hydrogeology

“…A review of emerging InSAR applications in hydrology and geomorphology found that some of the techniques were largely overlooked by the geographic and radar communities, and that the ability of InSAR to provide useful information to hydrologists and geomorphologists has been under-recognized (Smith 2002). Hydrogeologists have been relatively slow to use satellite remote sensing in their studies, attributed, in part, to the divide between the research community driving the instrument development and operation, and the hydrogeologic research community (Hoffmann 2005).…”

Minimizing the Residual Topography Effect on Interferograms to Improve DInSAR Results: Estimating Land Subsidence in Port-Said City, Egypt

“…There are different methodologies in differential interferometry (e.g., two-pass, three-pass, and four-pass interferometry) and with relatively new advanced algorithms (e.g., the Permanent Scatterers (PS) and the Small BAseline Subset (SBAS)) [9][10][11]. These techniques enable the mapping of subtle vertical surface movements (e.g., due to subsidence) down to millimeters [12][13][14][15][16][17].…”