Optimal use of AERONET measurements in UV-SWIR for the development and validation of satellite aerosol products

This study focuses on the use of state-of-the-art ground-based Earth observation measurements, primarily from the AERONET network, to support the development and validation of new aerosol retrieval approaches for current and future multi-platform satellite missions operated by EUMETSAT and Copernicus, such as EPS-SG (Metop-SG), Sentinel-3, Sentinel-5P, CO2M, the geostationary MTG, etc. These missions provide complementary photometric, polarimetric and spectrometric observations covering a broad spectral range from the ultraviolet (UV) to the short-wave infrared (SWIR) and thermal infrared (TIR).

 

A central objective of this work is to extend AERONET-based aerosol retrievals beyond their standard operational spectral range (440–1020 nm) towards both the UV and the SWIR. Recent developments allow the use of measurements from 340 nm in the UV to 1640 nm, and potentially up to 2200 nm, enabling a more consistent validation of satellite aerosol products across the full spectral domain. Many AERONET sites already provide long-term observations at 380–1640 nm, and a subset also includes measurements at 340 nm, forming a unique reference dataset for this purpose. AERONET-like retrievals at these extended wavelengths enable the evaluation of satellite-derived aerosol properties such as spectral refractive index, single-scattering albedo and size distributions, including fine-mode and super-coarse particles. These products are also essential for improving the treatment of aerosols in trace- and greenhouse- gases retrievals (e.g. NO₂ from UV,  CO₂ and CH₄ from SWIR).

 

The study presents the first aerosol inversions performed with the GRASP algorithm using this extended spectral range and describes the associated processing chain, including aerosol optical depth (AOD) and sky-radiance preparation, surface reflectance treatment, and inversion metadata. The preliminary results on the data collected at Rotterdam de Slufter during CINDI-3 campaign shows the good agreement in the data preparation and the inversion results derived from developed processing chain with the one from AERONET. This study found the importance of the treatment of the instrumental features such as spectral filter response. The results demonstrate the potential of long-term multi-spectral AERONET observations to strengthen the validation and development of next-generation satellite aerosol and trace- and greenhouse-gas retrievals.