Global trends in the aerosol optical, physical, and morphological properties obtained using multi-sensor measurements

Abstract

Numerous studies have been carried out to examine the trends in the rapidly changing aerosol loading through the total Aerosol Optical Depth (AOD) but very few investigations have acknowledged its long-term implications through the combined optical, physical, and morphological properties of the aerosols. Using a multivariate linear regression trend analysis model on nearly two decades (i.e., 2001–2020) of multi-source global datasets, we tried to relate the contribution of each of the varying aerosol properties such as scattering, absorption, size, and shape, to the changing total AOD trends of that sensor. Region-wise analysis has shown that the decrease (increase) in the total AOD trends observed over North-Eastern America, South America, Europe, North-Western Africa, and Eastern and Central China (Indian) regions are mainly in connection with the decrease (increase) in the fine-mode and scattering aerosols. However, the major increase over the South African region is from the increase in absorbing and scattering aerosols. Interestingly, the Indo-Gangetic Plain region of India, where high total AOD trends are observed, has seen a plausible slight decrease in its absorbing, non-spherical, and coarse-mode aerosols in recent years. This study also details the region-wise response accompanying the implementation of stringent mitigation strategies to ensure accurate quantification of the changing aerosol patterns in the atmosphere.