Estimation of soil moisture content from L- and P-band AirSAR data: A case study in Jeju, Korea

Abstract

Abstract-During the PacRim AirSAR campaign in Korea, the ground truth data about soil moisture content and surface roughness characteristics were collected. We intend to retrieve the surface parameters over the bare soil from multipolarization and multi-frequency AirSAR data. In this study, the theoretical scattering model, the IEM model is inverted by two existing algorithms -the multi -dimensional regression technique by Dawson et al.[1] and the inversion using 3-layer artificial neural networks (ANNs) [4]. As the first step, backscatter coefficients are calculated based on the ground truth information, and then training patterns are generated from within the valid ranges of surface parameters using the IEM model. The trained inversion models are tested to a set of AirSAR data a s well as synthetic data. Root mean square (RMS) errors of estimated soil moisture from the AirSAR data are average 3.1% in the regression and 4.2% in the inversion using the ANNs. The methods to improve the inversion accuracy are investigated. First, the normalization of signal parameters reduced the number of pixels that fail to reasonable results in the regression model. Second, the use of copolarization ratio as input units in the ANNs inversion scheme improve the soil moisture estimation, which results in an average RMS error of 2.9%.

Modelling electrical conductivity of soil from backscattering coefficient of microwave remotely sensed data using artificial neural network

“…The BC obtained from microwave depends on the frequency, polarization, incidence angle of radar configuration and surface parameters such as dielectric properties and Geocarto International 845 surface roughness. Kwon et al (2002) showed that the sensitivity of BC depends on the range of frequency, incidence angle, surface roughness and soil moisture content. It explained that BC has different polarizations depending on soil moisture and surface roughness parameters.…”