Effect of Ionospheric Faraday Rotation on Polarimetric Scattering Similarity

In this study, we are concerned with the effect of ionospheric Faraday rotation (FR) on polarimetric scattering similarity (PSS). To the best of our knowledge, this issue has not been investigated to date. Based on the FR-affected scattering matrix model, we first, by theoretical derivation, provide the expressions for three types of PSS parameter (PSSP) under the influence of FR, including the PSSP between a single scatterer and a canonical single scatterer, the PSSP between a mixed scatterer and a canonical single scatterer, and the PSSP between a mixed scatterer and a canonical mixed scatterer. According to these, we then theoretically analyze the variation of those FR-dependent PSSPs with FR by taking derivatives. We further conduct an experimental assessment on the L-band airborne AIRSAR quad-polarized data acquired in San Francisco by injecting different levels of FR into the data. Experimental results conform to the theoretical derivation.