Correlative HCHO measurements used as a reference for satellite validation are collected from several ground-based monitoring networks contributing to WMO's Global Atmosphere Watch:
- Fourier Transform Infrared (FTIR) solar absorption spectrometers: About 27 FTIR instruments perform network operation, in the framework of the Network for the Detection of Atmospheric COmposition Change (NDACC), from clean Arctic and oceanic sites to very-high-concentration sites such as Porto Velho, in the Amazon basin.
- Multi-Axis Differential Optical Absorption Spectroscopy UV-Visible spectrometers (MAX-DOAS): Several of those instruments perform network operation in the framework of the Network for the Detection of Atmospheric COmposition Change (NDACC).
Geographical distribution of the spectrometers contributing HCHO correlative measurements to the validation of Sentinel-5p: TROPOMI: 27 NDACC FTIR (yellow) and MAX-DOAS (magenta). (© Update of Vigouroux et al., AMT 2020).
Vigouroux, C. et al. NDACC harmonized formaldehyde time series from 21 FTIR stations covering a wide range of column abundances, Atmos. Meas. Tech., 11, 5049-5073 (2018), doi:10.5194/amt-11-5049-2018
Correlative data is obtained via the following channels:
- S5PVT AO projects CESAR (ID #28596, PI A. Apituley, KNMI) and NIDFORVAL (ID #28607, PI G. Pinardi and C. Vigouroux, BIRA-IASB) for rapid data delivery from NDACC MAX-DOAS and FTIR stations,
- the NDACC Data Host Facility, mirrored at EVDC and at BIRA-IASB for satellite validation purposes.