The Effect of Varying Moisture Content in the Retrieval of the Imaginary Part of Dielectric Constant from C-Band Frequency SAR

The imaginary part of dielectric constant (ε") was retrieved from SAR of C-band (5.36 GHz) frequency for three different moisture conditions, 25%, 50%, and 70%, using a semi-empirical model. The study has found that with 25% moisture content, the accuracy level of ε" has been considerably diluted (R2=0.702, RMSE=2.475, Bias=-2.244). The influence of roughness was observed to be higher in this particular condition. With 50% moisture content, the retrieval of ε" was significantly influenced by soil textural variations (R2=0.836, RMSE=1, Bias=-0.556) but not by surface periodicity. The simulation showed promising results (R2=0.885, RMSE=0.769, Bias=0.129) in saturated condition irrespective of the soil’s textural and roughness characteristics. The study has demonstrated that the C-band SAR is more significant in explaining ε" in a saturated state.