Synergistic Use of Far‐ and Mid‐Infrared Spectral Radiances for Satellite‐Based Detection of Polar Ice Clouds Over Ocean

Cloud phase is an important factor affecting cloud contributions to the polar energy budget. Brightness temperature differences (BTDs) between two mid-infrared (mid-IR) spectral channels are commonly used in satellite remote sensing determine phase, but mid-IR has limitations for determination regions. This study explores synergy far- and ice determinations over oceans. A far-IR BTD test (BTD449-521) developed based on variations of both scattering absorption properties “dirty window” region (400–600 cm−1 or 16.7–25 μm). Synthetic IR radiances at 1 resolution generated using ERA5 reanalysis data subset these spectra compare skill with “AIRS-Like” (BTD1231-960) combinations effective particle diameter (Deff_ice), optical depth (COD), top pressure (CTP). The performing better clouds smallest Deff_ice that we have studied (20 μm) due sensitivity size. was either comparable more successful than large sizes. For all Deff_ice, increasing COD leads enhanced signals stronger multiple mid-IR. Overall, performance strongly sensitive followed by CTP.