Potential of cloud and aerosol retrievals using highly accurate hyperspectral satellite imagery

Journal article

Abstract Reducing uncertainty in anthropogenic climate forcing requires improved observational constraints on aerosol and cloud properties. This study demonstrates how hyperspectral observations with exceptionally low radiometric uncertainty, exemplified by the proposed Traceable Radiometry Underpinning Terrestrial and Helio Studies (TRUTHS)-like configuration, can strengthen these constraints relative to Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) Ocean Color Instrument (OCI)-like configuration. Using forward radiative transfer simulations, we quantify the influence of radiometric uncertainty on spectral sensitivity to aerosol and cloud properties, including idealised layered aerosol–cloud configurations, with a focus on the O 2 A-band. At ±0.3% radiometric uncertainty, TRUTHS-like observations distinguish changes of ∼0.4 in cloud optical thickness (COT), ∼2 km in cloud top height, and ∼3 μm in effective radius (CER), approximately 0.01 in aerosol optical depth (AOD) and 0.02 in both single-scattering albedo and Ångström exponent (AE), demonstrating greater spectral sensitivity than the ±1.5% of PACE OCI-like uncertainty assumption. Lower radiometric uncertainty preserves subtle spectral differences between clean and aerosol-influenced clouds, enhancing discrimination among marine, continental, desert, and urban aerosol types under idealised within- and above-cloud configurations. A joint optimal-estimation information-content analysis across an ensemble of 100 simulated scenes shows that these spectral sensitivity differences translate into stronger simultaneous constraints on COT-CER and AOD-AE. Relative to PACE OCI-like observations, TRUTHS-like observations reduce mean posterior uncertainty by 46.97% (COT), 74.22% (CER), 24.39% (AOD), and 58.35% (AE), while mean degrees of freedom for signal (DFS) increase from 1.48 to 1.94 for clouds and from 1.29 to 1.57 for aerosols, with positive DFS differences across all scenes. Improved COT-CER constraints would underpin more accurate estimation of cloud droplet number concentration though that is not explored here. These results highlight the potential of low-radiometric-uncertainty hyperspectral observations to increase the information available to constrain aerosol and cloud properties, with implications for space-based aerosol–cloud characterisation, climate-model evaluation, and radiative-forcing assessments.

Authors: Mantri, S; Povey, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Environmental Research: Climate More from this journal
• Volume: 5
• Issue: 4
• Pages: 041004-041004
• Publication date: 2026-09-30
• DOI: 10.1088/2752-5295/aeae63
• EISSN: 2752-5295
• ISSN: 2752-5295
• Language: English
• Keywords: information content; cloud optical thickness; Ångström exponent; truth; O2 A-band; cloud droplet number concentration; hyperspectral satellite imagery; spectral sensitivity; aerosol-cloud interactions; radiometric uncertainty; single scattering albedo; cloud effective radius; optimal estimation; cloud top height; aerosol optical depth; anthropogenic forcing