IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (Jan 2021)
Temporal <italic>H</italic>/alpha Target Decomposition for Landslide Monitoring Using Ku-Band GB-SAR Time Series
Abstract
We investigate the applicability of the entropy (H)/ alpha $(\bar{\alpha })$ target decomposition realized by the temporally averaged coherency matrix, called temporal $H/(\bar{\alpha })$. We apply the temporal $H/\bar{\alpha }$ to ground-based synthetic aperture radar (GB-SAR) continuous monitoring data to characterize the scattering mechanism temporal change. As a case study, this work demonstrates the application of the temporal $H/\bar{\alpha }$ technique to landslide monitoring to detect and investigate the temporal scattering mechanism. The study acquired long-term GB-SAR polarimetric data over the postlandslide slope, Minami-Aso, Kumamoto, Japan. The study first investigated the property of the temporal $H/\bar{\alpha }$ parameters over selected land cover types by comparing it with that derived by spatial averaging (spatial $H/\bar{\alpha }$) to explain the landslide monitoring results. Also, the rainfall effects on the temporal H/$\bar{\alpha }$ parameters are demonstrated. The temporal H and $\bar{\alpha }$ values increase up to 0.07$^\circ $ and 13.54$^\circ $, respectively, when the rainfall rate is 52.5 mm/h. The time-series analysis of the temporal $H/\bar{\alpha }$ indicates an obvious temporal transition of the scattering mechanism and a change of the backscattering stationarity when a landslide occurs. The applicability of the temporal $H/\bar{\alpha }$ for the change-detection is discussed by comparing it with the classical spatial $H/\bar{\alpha }$ parameters.
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