InSAR contributions to water status retrieval

Abstract:
The interferometric phase of synthetic aperture radar is very sensitive to water content variations. Phase information can contribute to the retrieval of water status for soils and vegetation, along with backscatter change measurements. There is some complementarity between backscatter and phase, both in the space and in the time domain. Dry areas in particular present challenges to backscatter techniques, whereas they are typically favourable for interferometric applications considering the high coherence. Regarding the time dimension, interferometric measurements have temporal limitations related to coherence; instead, the backscatter can be compared between long distant dates and provide the backbone of long time series. Vegetated areas subject to strong decorrelation typically reveal a short-term closure phase signal that seems to be related to biomass accumulation, potentially a unique signal that can have advantages over other indices which are subject to saturation at a certain biomass level.