Dominant Remote Sources and Their Potential Contributions to Airborne Dust over Typical Asian Regions

Dust aerosols are a major component of atmospheric aerosols, impacting climate systems and human health. In Asia, dust storms pose significant threats to air quality and public health, particularly in China, Korea, and Japan. Additionally, dust deposition in China's coastal regions supplies trace elements and nutrients that influence microbial communities, affecting marine productivity. Over the Tibetan Plateau, dust reduces snow and ice albedo, accelerating glacial melting. Given these impacts, understanding the sources and contributions of dust aerosols is crucial. Therefore, we focused on typical regions in Asia—North China, Southeast China, the Korea-Japan region, the East China Sea, and the Tibetan Plateau—and selected four primary dust source regions: Eastern Central Asia (ECA), Western Central Asia (WCA), West Asia-South Asia (WA-SA), and North Africa-Middle East (NA-ME).

Previous studies on tracing the sources of airborne dust have largely relied on back-trajectory analysis. However, simply using the number of air mass trajectories passing over a desert to determine dust sources can lead to an overestimation of the relative contribution from source regions. This method, which did not consider the dust load in the transported air masses, resulted in an inaccurate evaluation of the desert-source contribution to the study regions. To address this issue, we present a novel algorithm for source-tracing of airborne dust (STAD), which incorporates satellite and reanalysis-based estimates to more precisely track dust activity and provide a more accurate quantification of source contributions. Overall, ECA emerges as the dominant source of dust affecting East Asia. In regions such as North China and the Korea-Japan area, ECA accounts for 60%-70% of dust transport, with WCA contributing around 20%. In Southeast China and the East China Sea, ECA still plays a major role, contributing 40%-50% of the dust. The Tibetan Plateau, as a dust transit hub in the Northern Hemisphere, has a complex dust source composition. The airborne dust at high altitudes over the Tibetan Plateau shows considerable spatial variation and primarily comes from desert clusters in ECA, WCA, and WA-SA. The Karakum, Taklimakan, and Thar deserts are significant sources of high-altitude airborne dust in the northwest, northeast, and southwest regions of the TP, with average mass loadings (mg m⁻²) contributing rates of 42.2% (32.9), 49.6% (48.3), and 16.4% (32.1), respectively.

This research lays a solid foundation for future studies on the role of dust aerosols in the Asian climate system, including their impacts on water cycles, weather patterns, and long-term environmental changes, providing crucial insights for developing effective mitigation strategies.