Chun Sik Chae (JPL, USA); Shailen Desai (JPL, USA)

The Sentinel-6B is the newest reference satellite altimetry mission. It includes a radar altimeter, a precision orbit determination suite and a radiometer to measure wet tropospheric path delay. The AMR-C radiometer on Sentinel-6B is identical in design to the radiometer on Sentinel-6A. It includes the same innovations compared to the prior Jason-series missions; a secondary calibration system external to the radiometer that is used to stabilize the wet path delay measurement to 0.7mm/yr over 5+ years and a high-frequency radiometer (termed HRMR) with <5km spatial resolution that improves the measurement near land and sea ice boundaries. We will present the performance of the AMR-C and HRMR radiometer systems on Sentinel-6B during the cal/val phase and tandem orbit with Sentinel-6A. We will summarize results from special calibration tests that were conducted during the cal/val period that characterize the radiometer and external calibration system. We also compare Sentinel-6B to Sentinel-6A during the tandem phase. We find excellent agreement between these two systems and are able to precisely quantify the relative long-term stability that the external calibration system provides.