Polarimetric Ratio-Based Screening for Enhanced External Calibration of HY-4 LASMR

The two-dimensional L-band Aperture Synthesis Microwave Radiometer (LASMR) aboard China's HY-4 ocean salinity satellite faces significant on-orbit calibration challenges, primarily from ionospheric disturbances, solar radiation, and radio frequency interference (RFI). To address this, we develop a novel screening framework that leverages the instrument's full-polarization measurement capability. The core of this framework is a new polarimetric ratio screening (PRS) method, which effectively iden