IDEAS-QA4EO DOAS-BO: Towards a new FRM4DOAS site in the Po valley

The Po valley (Italy) is one of the most polluted regions in Europe. High NO₂ concentrations are often found due to industrial and urban activities and its particular geographical position. However, MAX-DOAS instruments, compliant to the Fiducial Reference Measurements for Ground-Based DOAS (FRM4DOAS) standards were not present in the Po Valley. At the beginning, the purpose of the IDEAS-QA4EO “DOAS-BO: Towards a new FRM4DOAS site in the Po valley" WPs (contract funded by ESA-ESRIN n. 4000128960/19/I-NS) was to fill this gap exploiting TROPOGAS, a custom-built spectrometer developed at CNR-ISAC institute. For this reason, we evaluated its performances and the synergies with in-situ and satellite data during a measurement campaign on the CNR-ISAC roof (Bologna). TROPOGAS was then supposed to be involved in another campaign at BAQUNIN supersite (Rome) to assess the synergies with the Pandora#117 instrument. However, since CNR-ISAC bought a new instrument (SkySpec-2D) compliant to FRM4DOAS requirements, in the frame of an Italian project, we decided to: first, assess the synergy between SkySpec-2D and TROPOGAS, during a measurement campaign in Bologna, and second, move the SkySpec-2D to Rome for the measurement campaign in BAQUNIN against Pandora#117. The results of all the campaigns involve the retrieved NO₂ Vertical Column Densities (VCDs).