This session is dedicated to challenges and recent advances in ozone measurement techniques and observation networks as well as data processing methodologies. We invite presentations on ground- based observations, airborne measurement platforms as well as satellite remote sensing measurements of tropospheric, stratospheric and mesospheric ozone. Careful calibration, validation and characterization of the observations and their uncertainties, like potential drifts, dependences on auxiliary data or other assumptions are key issues for reliable observations. In order to create long-term datasets, merging of data from different instruments is needed and proper data characterization is further emphasized. All aspects related to ozone measurement techniques, data processing methodologies, comparison between various techniques and results of ozone measurement campaigns are welcome for this session.