Evaluation of TEMPO HCHO retrievals using co-located FTIR and Pandora observations
Ortega, I., Hannigan, J. W., Edwards, D. P., Gaubert, B., Stremme, W., et al. (2026). Evaluation of TEMPO HCHO retrievals using co-located FTIR and Pandora observations.
| Title | Evaluation of TEMPO HCHO retrievals using co-located FTIR and Pandora observations |
|---|---|
| Genre | Conference Material |
| Author(s) | Ivan Ortega, James W. Hannigan, David P. Edwards, Benjamin Gaubert, W. Stremme, M. Grutter, A. Cadena-Caicedo, K. Strong, V. Flood, X. Zhao, G. González Abad, C. R. Nowlan |
| Abstract | Formaldehyde (HCHO) is an important indicator of volatile organic compound emissions and photochemical activity, with significant implications for air quality and atmospheric chemistry. The recently launched geostationary Tropospheric Emissions: Monitoring of Pollution (TEMPO) satellite mission provides the first-ever hourly observations of HCHO over North America from space. To evaluate the accuracy of TEMPO HCHO total column retrievals, we compare them with co-located ground-based measurements from Fourier Transform InfraRed (FTIR) and Pandora spectrometers at three sites: Boulder, Colorado; Mexico City; and Toronto, Canada. We first assess the consistency between FTIR and Pandora HCHO total column measurements to characterize the performance of Pandora instruments relative to the established FTIR retrievals. This long-term comparison is important given the rapid global expansion of Pandora spectrometers and the limited overlap with reference instruments. Our results show good correlation and consistent seasonal patterns between FTIR and Pandora. However, our analysis underscores the need for routine field calibration and performance assessments of Pandora measurements, particularly after the first two years of Pandora deployment, to ensure long-term data reliability. Building on the agreement between the two independent ground-based datasets, FTIR and Pandora, we enhance the robustness of the TEMPO evaluation and increase confidence in the assessment of its HCHO retrievals. TEMPO Level 2, Version 3 retrievals exhibit a consistent low bias of approximately 30% relative to ground-based observations across all three sites, with the largest discrepancies occurring under elevated HCHO conditions. Nonetheless, TEMPO accurately captures both the diurnal and seasonal variability of HCHO, demonstrating its utility for characterizing short-lived atmospheric species. Beyond the direct comparison with ground-based observations, we also apply a bias-corrected TEMPO dataset to model evaluation, specifically with NCAR MUSICA v0, further highlighting the value of integrating satellite products with modeling frameworks to improve the representation of atmospheric composition. |
| Publication Title | |
| Publication Date | Jan 27, 2026 |
| Publisher's Version of Record | |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d7jm2g53 |
| OpenSky Listing | View on OpenSky |
| ACOM Affiliations | ACRESP |