Improvement the spatiotemporal resolution of atmospheric aerosol optical properties using elastic lidar measurements

Abstract

Lidar technique is an active remote sensing technique that enables the retrieval of the optical properties of aerosol particles suspended in the atmosphere. This work presents an improvement in the spatiotemporal resolution of these properties using the ALHAMBRA lidar system, operated by Group of Physics of the Atmosphere (GFAT). Through the implementation of alternative inversion algorithms—specifically, the quasi-backscatter and iterative backscatter algorithms— the particle backscatter coefficient has been retrieved with high spatiotemporal resolution which allows obtaining a set of high resolution intensive aerosol properties. These algorithms require a precise estimation of the lidar system’s calibration factor as input. To this end, three calibration methods have been rigorously evaluated: the direct calibration method and two new approaches based on linear fits of the signal to attenuated backscatter and aerosol optical depth. These methods have been validated using synthetic lidar signals and have demonstrated robust performance when applied to real data under stable atmospheric conditions. Additionally, overlap correction strategies have been studied to extend the range over which aerosol optical properties can be accurately visualized. In this context, a new overlap algorithm has been developed and validated, based on the assumption of a homogeneous atmosphere in the near-field region. This method showed excellent agreement with the traditional iterative algorithm, both in simulations and in real measurements. The high-resolution visualization of intensive and extensive aerosol properties has enabled a detailed analysis of atmospheric events of interest. These representations facilitated the classification of atmospheric structures—like Saharan dust, anthropogenic pollution, and clouds—and the identification of interaction zones between them. Furthermore, they allowed for a more detailed study of particle dynamics within the boundary layer. The results confirm the robustness and applicability of the proposed methodologies, establishing a solid foundation for future work. In particular, these advances lay the groundwork for more accurate and robust atmospheric monitoring.