10.26165/JUELICH-DATA/GLTKXZHermanns, AlexanderAlexanderHermanns0009-0007-9974-4307Forschungszentrum JülichLange, Anne CarolineAnne CarolineLange0000-0001-8027-5933Forschungszentrum JülichFuchs, HendrikHendrikFuchs0000-0003-1263-0061Forschungszentrum JülichKowalski, JuliaJuliaKowalski0000-0003-4123-5896RWTH Aachen universityFranke. Philipp0000-0001-6298-164XForschungszentrum JülichJülich DATA2025Earth and Environmental SciencesK-Meanair qualityclusteringData assimilationFranke, PhilippPhilippFrankeForschungszentrum Jülich2025-12-032025-12-0410.5281/zenodo.1471188110.5194/gmd-18-9417-20251.0CC0 WaiverPreprocessing routine for ground-based atmospheric monitoring network data. Utilizing a k-means soft constrained clustering algorithm to derive a representative sub-sampling of the availiable data into an assimilation and validation set. This work was partially performed as part of the Helmholtz School for Data Science in Life, Earth and Energy (HDS- LEE) and received funding from the Helmholtz Association of German Research Centres.