Exploring the aerosol-cloud transition zone from advanced all-sky camera observations

Francesco Scarlatti; Javier Tarín; José Luis Gómez-Amo; Pedro C. Valdelomar; M. Pilar Utrillas

doi:10.1117/12.2689229

19 October 2023 Exploring the aerosol-cloud transition zone from advanced all-sky camera observations

Francesco Scarlatti, Javier Tarín, José Luis Gómez-Amo, Pedro C. Valdelomar, M. Pilar Utrillas

Proceedings Volume 12730, Remote Sensing of Clouds and the Atmosphere XXVIII; 127300U (2023) https://doi.org/10.1117/12.2689229
Event: SPIE Remote Sensing, 2023, Amsterdam, Netherlands

Conference Poster

Abstract

Aerosols and clouds have been scientifically considered distinct from theoretical point of view. The two components share the same physical meaning, namely particles suspended in the air, even if the chemical or physical features can differentiate. Form the radiometric view it has been a challenging task to separate the two atmospheric components in an exact way. Recently scientists are also discussing about a continuum between aerosols and clouds. In this study we use calibrated images of an all-sky camera with the aim of exploring the features that can differentiate the two regions in terms of radiometric magnitudes. An intense smoothing is applied, and the spatial derivatives are performed on the red channel radiances. These derivatives are almost zero in the cloud-free area and sensibly different from zero in the rest of the image. Applying dynamic thresholds to Blue-to-Red Ratio (BRR), we further determine the cloudy region of the sky. Then, we define aerosol-cloud transition zone as the non-cloudy sky zone with intense directional derivatives of the radiances in the red channel. This transition zone shows different radiometric characteristics with respect to cloud and cloud-free regions, for example in terms of BRR distribution of the pixels.

(2023) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Francesco Scarlatti, Javier Tarín, José Luis Gómez-Amo, Pedro C. Valdelomar, and M. Pilar Utrillas "Exploring the aerosol-cloud transition zone from advanced all-sky camera observations", Proc. SPIE 12730, Remote Sensing of Clouds and the Atmosphere XXVIII, 127300U (19 October 2023); https://doi.org/10.1117/12.2689229

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