Theoretical study of two‐frequency coherence of MST radar returns

摘要: The theoretical expressions of two-frequency coherence the MST radar returns from an atmospheric thin layer with sharp boundaries, which embeds within volume and cannot be resolved by conventional techniques, are derived in this article. It shows that frequency domain interferometry (FDI) is not only function thickness components wave vector, but also related to wavenumber power spectrum refractivity irregularities. A quantitative examination FDI indicates effect irregularity on negligible for law spectral model, while it ignored other forms, example, a Gaussian model. zenith angle dependence investigated According observations made Chung-Li VHF radar, ratio observed at vertical 17° off-zenith between 1.3 2.4. This feature can illustrated satisfactorily using theory developed echoing mechanism studied, showing expression turbulent scattering treated identical Fresnel reflection as long condition Δk/k ≪ 1 met. result implies seems impossible identify technique. problem estimating having boundaries exp (−Δk2σ2r) discussed. suggests pertinent formula used estimate L = 2.364σr. comparison work results text.