Analysis of Aerosol Type and Fine- and Coarse-mode Aerosol Direct Radiative Forcing over Regions in East and Southeast Asia Based on AERONET Version 3 Data

Abstract

Utilizing particle linear depolarization ratio (PLDR) and single scatter albedo (SSA) at 1020 nm from AERONET (Aerosol Robotic Network) Version 3 Level 2.0 data, we distinguish seven kinds of aerosol types (including the pure dust, dust-dominated aerosol, pollution-dominated aerosol, non-absorption aerosol, weak absorption aerosol, medium absorption aerosol and strong absorption aerosol) to explore the spatial and temporal distributions of aerosol components, the radiative effect of fine-and coarsemode aerosol. We use observations from stations located in five regions: northern China, northwest Asia, the Tibetan Plateau, southern China and Southeast Asia. Fine-mode aerosol dominates in northern China, while coarse-mode aerosol is prevalent in northwest Asia. Fine-mode aerosol also plays a crucial role in the Tibetan Plateau, southern China and Southeast Asia. The highest radiative forcing efficiency (110.3 W m-2) for fine-mode aerosol in the plateau region is corresponding to high concentrations of strong absorption (SA) aerosol. Lowest radiative forcing and radiate forcing efficiency both appears during summer in southern China. Aerosol components are clearly distinct for the spatial and temporal distributions in Southeast Asia. SA aerosol

Absorbing Aerosol Optical Properties and Radiative Effects on Near-Surface Photochemistry in East Asia

“…Additionally, higher AAE appears in Beijing site throughout the year, especially in spring. More coarse aerosol particles from the deserts stretching far and wide in northwest China and Central Asia would be transported to north China due to the Mongolian cyclones [151][152][153], and the dust-dominated aerosols in the northwest mainly take two paths to affect the northern and eastern China, one of which is from Inner Mongolia, passing through Hebei, Beijing, Shandong, and, finally, Jiangsu, and the other is from Shaanxi, Shanxi, Henan, Anhui, and, finally, Jiangsu [154,155]. Therefore, more exposure to sand and dust events in spring may lead to the larger size of absorbing aerosol particles at the Beijing site.…”