Development of a merged HCHO climate data record from the EUMETSAT AC SAF GOME-2 Level-2 products

<p>Within the framework of the EUMETSAT AC SAF project, the production of climate data records (CDRs) of short lived O₃ precursors (HCHO and NO₂) is under development, based on the three GOME-2 instruments and the future S5 and S4 Copernicus platforms.</p> <p>This work presents the development of the formaldehyde CDR, combining the current GOME-2 A, B and C operational AC SAF Level-2 orbital products to create one single L3 averaged product using advanced gridding tools. To this aim, the consistency between the three GOME-2 instrument needs to be improved by means of suitable correction schemes accounting for inter-sensor biases due to inconsistent auxiliary data or instrumental issues. The use of the CAMS model reanalysis as a source of prior HCHO profiles is explored with the aim to produce one consistent dataset from 2007 to now. Estimation of the random and systematic uncertainty is included for each grid cell. Furthermore, we plan to include meteorological re-analysis data (surface temperature and winds) in the output files to further support the interpretation of the data and of their observed variations.</p> <p>Validation results of this new monthly averaged CDR dataset will be presented, with a special focus on bias, precision and stability in time. To this aim, long-term ground-based HCHO measurements are collected and assessed.</p>