Speaker Folkert Boersma (KNMI R&D Satellite Observations, Wageningen University)
What is the quality of satellite data? How useful is satellite data for my particular application? According to the philosopher Robert Pirsig (Zen and the Art of Motorcycle Maintenance), ‘quality’ itself cannot be properly defined because it exists as a perceptual experience. Still, every human being has a good sense of what ‘quality’ or ‘value’ means and how to work with it. In this presentation I will show how we have addressed the wide diversity in quality aspects if satellite data within the KNMI-led FP7-SPACE project Quality Assurance for Essential Climate Variables (QA4ECV). The QA4ECV project (www.qa4ecv.eu) was initiated in 2014 to demonstrate how reliable and traceable quality information can be provided for multi-decadal satellite measurements of climate and air quality parameters. We generated an improved, harmonized dataset of tropospheric NO2 columns from the GOME, SCIAMACHY, GOME-2, and OMI sensors for the period 1995-2017. In generating this data record, we went through a complete cycle of quality assurance steps: from involving user requirements, via algorithm intercomparison tests and provision of detailed uncertainty information, to ultimate product validation. I will conclude my presentation with some examples of how the new QA4ECV NO2 data are already being used for various scientific applications.