TROPOMI tropospheric O3 data are obtained using the Convective Cloud Differential technique, which results in a daily, gridded measurement for the tropical belt (0.5o latitude by 1.0o longitude). Each TROPOMI measurement represents the 3-day average of the O3 column between the surface and 270 hPa under cloud-free conditions.
The operational MPC VDAF validation data stream includes comparisons of Sentinel-5p data to co-located measurements by ozonesondes. The ozone profiles at high vertical resolution acquired by these sondes are screened, then integrated over the same vertical domain as the TROPOMI product (surface to 270 hPa) prior to comparison. Additional intercomparisons of TROPOMI to other satellite sensors (EOS-Aura OMI, MetOp-B GOME-2) are regularly conducted by the MPC team as well.
Details on the methodology and results are described in Hubert et al. (2021).
- Hubert, D. et al., TROPOMI tropospheric ozone column data: geophysical assessment and comparison to ozonesondes, GOME-2B and OMI, Atmos. Meas. Tech., 14, 7405–7433, doi:10.5194/amt-14-7405-2021, 2021.