High Resolution Microwave Radiometer

The High Resolution Microwave Radiometer is an experimental millimetre-wave subsystem within the AMR-C microwave-radiometer context on Sentinel-6A and Sentinel-6B, scoped to coastal altimetry correction rather than an independent mission payload.^[1] It uses 90, 130 and 168 GHz channels, complementing AMR-C heritage 18.7, 23.8 and 34 GHz channels used for wet-tropospheric correction.^[1] Its role is to extend microwave wet-tropospheric retrievals closer to coasts under cloud-free conditions and to support Poseidon-4 high-resolution SAR mode.^[1] For satellite-altimetry users, the relevant application is coastal wet-tropospheric path-delay correction support where land proximity makes standard radiometer correction harder.^[1] HRMR is an experimental supporting capability with no independent HRMR mission requirements or objectives.^[1]