Monitoring ocean circulation at high resolution in both space and time is of paramount importance for under-standing and modelling the ocean-atmosphere climate system, especially in coastal areas. Spaceborne radar al-timeters have been used to successfully monitor ocean circulation on a global scale ( > 30km) in the deep ocean when the geostrophic approximation is generally valid. The ocean structures seen in high-resolution satellite measurements at meso (10-100km) and sub-mesoscale ( 3m/s). The performance tool is based only on numerical models without assumptions and calculates the reflected power and the Doppler characteristic of each backscattering cell of the illuminated sea surface in dependency on the ra-dar properties, the acquisition geometry, and the flight parameters. The performance of the instrument for the baseline design achieves a swath width larger than 2km in case of wind speed of 3m/s. The noise equivalent sigma zero (NESZ) is between -30dB and -45dB and the radiometric resolution is better than 0.1dB. The veloci-ty accuracy that the system can obtain is fulfilled from look angles lower than 20 degrees up to look angles above 63 degrees, resulting in more than 3km of swath available. A first airborne verification of the instrument was performed in July 2021 by means of a test flight over land. The results confirmed a high SNR and coherency close to 1 for all channels (broadside and squinted). Internal calibration data showed the high stability of the instrument, well within requirements. The validation is continuing this winter with airborne data acquisitions over corner reflectors, flat land and over water. A functional test campaign over ocean is planned in spring 2022 in the Iroise Sea to verify the end-to-end func-tionality and performance of the fully integrated instrument, including internal calibration capabilities, and of the processor by means of on-ground testing and flight tests

Living Planet Symposium, 23-27 May 2022, Bonn, Germany

Peer reviewed