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Validation Summary

The Sentinel-5p TROPOMI L2 CO data product (total CO column) is in good overall agreement with correlative ground-based measurements from NDACC and TCCON. Bias and dispersion estimates (see Table below) meet the mission requirements.

Product ID Stream Product Bias Dispersion Special features
 L2_CO NRTI CO column +2% 8% Along orbit stripes. Destriped CO data available in collection 3.
4% SZA dependence of bias and ±2% seasonal depedence in bias.
RPRO/OFFL CO column +2% 8%


The averaged correlation coefficient reaches 0.9 for the TCCON network and NDACC sites


 Mosaic CO TCCON

Plots show the weekly mean relative differences for the S5P RPRO/OFFL CO columns against NDACC (top) and TCCON (bottom) sites. Sites are sorted by decreasing latitude.

For more information please consult the latest issue of the Sentinel-5p Routine Operations Consolidated Validation Report (ROCVR).


Latest Quarterly Validation Report Product info Current Processor Version
#22: April 2018 - February 2024 See


Details of the validation setup can be found in the latest quarterly validation report and in Sha, M. K., et al.: Validation of methane and carbon monoxide from Sentinel-5 Precursor using TCCON and NDACC-IRWG stations, Atmos. Meas. Tech., 14, 6249–6304,, 2021.

NDACC is a cross-border international research network of remote sounding stations. It is a major contributor to the World Meteorological Organisation (WMO) GAW programme and it works under the auspices of United Nations Environment Programme (UNEP) and the International Ozone Commission (IO3C). At present time it includes more than 70 high-quality, remote-sensing research stations/sites distributed worldwide. Within the MPC VDAF we rely on the NDACC FTIR CO measurement data which provide vertical CO concentration profiles with a limited vertical resolution.


The Total Carbon Column Observing Network (TCCON), established in 2004, is a network of ground- based Fourier Transform Spectrometers that measures column-averaged abundances of atmospheric constituents including CO2, xCH4, N2O, HF, CO, H2O, and HDO. TCCON was included in the Global Atmosphere Watch (GAW) of the WMO in 2009.

NDACC TCCON world view August 2020

NDACC and TCCON sites

The Sentinel-5p Mission Performance Centre provides an operational validation service relying on the VDAF Automated Validation Server (VDAF-AVS).  This fully automated data analysis system collects correlative measurements from quality-controlled monitoring networks and compares them to Sentinel-5p data using community endorsed protocols.  It outputs a suite of traceable quality indicators enabling users to judge the fitness-for-purpose of the Sentinel-5p data.

The illustration given hereafter shows the automated comparison of Sentinel-5p total CO column data with respect to correlative measurements aquired by an FTIR instrument of the NDACC network.  More CO validation results are available at



Latest Issue

Quarterly Validation Report of the Copernicus Sentinel-5 Precursor Operational Data Products #22: April 2018 - February 2024


Previous issues of the quarterly validation report are archived here.