Task 3 will focus on the harmonization of continuous and sustainable data streams from the six supersite stations involved in the second phase of HD(CP)². Beside JOYCE, LACROS, CESAR, and RAO, there are the sites UFS (Umweltforschungsstation Schneefernerhaus) and BCO (Barbados Cloud Observatory). The main tasks will be to coordinate developments for harmonized ceilometer, microwave radiometer and cloud radar calibration and quality control procedures in collaboration with the instrument manufacturers and international partners, i.e. from ACTRIS and ARM-ASR. Additionally, further develop and implement observational uncertainty characterisation is necessary. This task will also coordinate the measurement configuration of the different instruments.