NDACC: Network for the Detection of Atmospheric Composition Change

PGN: Pandonia Global Network

QA4ECV: Quality Assurance for Essential Climate Variables

NORS: Demonstration Network Of ground-based Remote Sensing observations in support of the Copernicus Atmospheric Monitoring Service 

CAMS: Copernicus Atmospheric Monitoring Service

CINDI-2Cabauw Intercomparison of Nitrogen Dioxide Measuring Instruments 2

MADCAT: Multi Axis Doas - Comparison campaign for Aerosols and Trace gases

ESA Earth Observation Data