Importance of subpixel Earth surface reflectance and altitude for atmospheric trace gas retrievals from passive satellite instruments

Weimer, Michael; Reuter, Maximilian; Hilker, Michael; Noël, Stefan; Buchwitz, Michael; Meijer, Yasjka; Lang, Rüdiger; Marshall, Julia; Bovensmann, Heinrich; Burrows, John P.; Bösch, Hartmut

doi:10.5194/amt-19-5425-2026

Articles | Volume 19, issue 16

https://doi.org/10.5194/amt-19-5425-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/amt-19-5425-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 16

Research article

|

21 Aug 2026

Research article |

| 21 Aug 2026

Importance of subpixel Earth surface reflectance and altitude for atmospheric trace gas retrievals from passive satellite instruments

Michael Weimer, Maximilian Reuter, Michael Hilker, Stefan Noël, Michael Buchwitz, Yasjka Meijer, Rüdiger Lang, Julia Marshall, Heinrich Bovensmann, John P. Burrows, and Hartmut Bösch

Supplement

https://doi.org/10.5194/amt-19-5425-2026-supplement

Data sets

HLS Sentinel-2 Multi-spectral Instrument Surface Reflectance Daily Global 30 m v2.0 J. Masek et al. https://doi.org/10.5067/HLS/HLSS30.002

Copernicus Digital Elevation Model, 90 m resolution (GLO-90) Copernicus Programme https://doi.org/10.5270/ESA-c5d3d65

ERA5-Land hourly data from 1950 to present Copernicus Climate Change Service (C3S) https://doi.org/10.24381/cds.e2161bac

Short summary

Greenhouse gas column measurements from space using reflected sunlight have to make assumptions about the Earth's surface elevation. Usually, it assumed that the elevation representing the satellite's spatial sample is the unweighted average of high-resolution surface elevation data. We find and show with many examples that the surface elevation should be weighted by the surface reflectance in the respective wavelength bands. This improves errors in the retrieval of trace gases.