From 2022/10/01, an anomaly was observed on the wet-troposphere correction derived from the microwave radiometer on Sentinel-6 Michael Freilich, applied in the sea level processing.

From 2022/10/01, an anomaly was observed on the wet-troposphere correction derived from the microwave radiometer on Sentinel-6 Michael Freilich, applied in the sea level processing. This correction indeed shows an abnormal drift of around -2mm/month from early October to mid-December 2022 and remains underestimated (~-5mm) from mid-December 2022 (see figure). 

This anomaly has a direct impact in the sea surface height and sea level anomaly deduced from Sentinel-6 Michael Freilich in L2P products with an abnormal drift of ~+2mm/month from early October to mid-December 2022 and a mean bias of ~5mm from mid-December 2022. Users of L2P products are encouraged to use these products with caution for applications from October 2022 onwards, until a correction is implemented. 

A calibration of the microwave radiometer measurements fixing this issue is currently in progress. It will be taken into account in the L2 NRT/STC production as soon as possible to generate a correct wet-trophere correction. However, an impact for the user is to be expected with the introduction of a jump (~+5mm) on the SLA from the time this new calibration is taken into account in the L2 production. This is expected around January 23, 2022.