Sensitivity and Information-Content Assessment of a Candidate Channel Configuration for the Terahertz Ice Cloud Imager Proposed for Next-Generation Fengyun Meteorological Satellites

Terahertz observations are sensitive to ice-cloud scattering but require thermodynamic context and balanced spectral sampling. This study evaluates a candidate six-band Terahertz Ice Cloud Imager (TICI) configuration for next-generation Fengyun polar-orbiting meteorological satellites. Atmospheric absorption, ice-cloud scattering, and polarization sensitivity below 1 THz are simulated with the Atmospheric Radiative Transfer Simulator. Information content is assessed using 12 Weather Research and Forecasting (WRF)-derived representative composites and 200 individual midlatitude-ocean profiles. The configuration combines water-vapor observations near 183 and 380 GHz, temperature-sensitive observations near the 424 GHz oxygen band, and window observations near 243, 664, and 874 GHz. Compared with the 11-observation Ice Cloud Imager (ICI) reference, the 21-scalar-observation TICI vector provides more temperature and water-vapor degrees of freedom for signal (DFS) under both channel-specific and uniform 1 K noise. Under uniform 1 K noise, the twelve-scene mean frozen-hydrometeor DFS is 4.117 for TICI and 4.034 for ICI; the small increase is concentrated mainly in mean-particle-mass states. Band-removal and equal-dimensional tests show complementary roles for 380, 424, and 874 GHz and indicate that the thermodynamic gain is not solely due to observation count. The conceptual antenna architecture achieves simulated main-beam efficiencies above 95%, while forward-model error, receiver implementation, and footprint co-registration remain to be assessed.