ATMOSFER, a CNES-supported 2024 balloon campaign in Kiruna, Sweden, prepared ESA’s FORUM mission by measuring far-infrared radiation, water vapor, clouds and aerosols in the UTLS. FIRMOS-B (balloon borne demonstrator of FORUM) showed excellent performance, while hygrometers agreed closely. The campaign observed cirrus clouds, ice crystals and stratospheric aerosol layers linked to wildfire and tropical air masses, improving climate observations and FORUM validation.

The topic is finding methods to extend climate data records from single-instrument satellite observations, in this case the Advanced Very High Resolution Radiometer (AVHRR). Several modern instruments include AVHRR-heritage channels, but some corrections are necessary to account for some differences. We have simulated AVHRR data from the Visible Infrared Imaging Radiometer Suite (VIIIRS) sensor on National Oceanic and Atmospheric Administration (NOAA) polar satellites. We find that methods based on machine learning are capable of performing these corrections.

A balloon-borne instrument collects ice particles on a plastic film strip as it ascends through cirrus clouds. The produced images show ice particles, but also a background revealing features. Manual analysis is time consuming, so two machine learning models have been developed to first detect the ice particles and then classify their shape. The results of these models agree well with manual analysis, thus analysis can be automated using these models.

This paper describes CLAAS-3, the third edition of the Cloud property dAtAset using SEVIRI, which was created based on observations from geostationary Meteosat satellites. CLAAS-3 cloud properties are evaluated using a variety of reference datasets, with very good overall results. The demonstrated quality of CLAAS-3 ensures its usefulness in a wide range of applications, including studies of local- to continental-scale cloud processes and evaluation of climate models.

This paper presents a global climate data record on cloud parameters, radiation at the surface and at the top of atmosphere, and surface albedo. The temporal coverage is 1979–2020 (42 years) and the data record is also continuously updated until present time. Thus, more than four decades of climate parameters are provided. Based on CLARA-A3, studies on distribution of clouds and radiation parameters can be made and, especially, investigations of climate trends and evaluation of climate models.