Spatial source contribution and interannual variation in deposition of dust aerosols over the Chinese Loess Plateau

Abstract

The Chinese Loess Plateau (CLP) in northern China serves one of the most prominent loess records in the world. The CLP is an extensive record of changes in past aeolian dust activity in East Asia; however, the interpretation of the loess records is hampered by ambiguity regarding the origin of loess-forming dust and an incomplete understanding of the circulation forcing dust accumulation. In this study, we used a novel modeling approach combining a dust emission model FLEXDUST with simulated back trajectories from FLEXPART to trace the dust back to where it was emitted. Over 21 years (1999-2019), we modeled back trajectories for fine (~ 2mu) and super-coarse (~ 20mu) dust particles at six CLP sites during the peak dust storm season from March to May. The source receptor relationship from FLEXPART is combined with the dust emission inventory from FLEXDUST to create site-dependent high-resolution maps of the source contribution of deposited dust. The nearby dust-emission areas dominate the source contribution at all sites. Wet deposition is important for dust deposition at all sites, regardless of dust size. Non-negligible amounts of dust from distant emission regions could be wet deposited on the CLP following high-level tropospheric transport, with the super-coarse dust preferentially from emission areas upwind of sloping topography. On an interannual scale, the phase of the Arctic Oscillation (AO) in winter was found to have a strong impact on the deposition rate on the CLP, while the strength of the East Asian Winter Monsoon was less influential.

Spatial Source Contribution and Interannual Variation in Deposition of Dust Aerosols Over the Chinese Loess Plateau

“…The FLEXDUST‐EA 3‐hourly spring dust emission inventory (Haugvaldstad, 2023a) and the post‐processed FLEXPART 3‐hourly, 10‐day backward spring ES and source contributions from 1999 to 2021 (Haugvaldstad, 2023b) are available from the Norwegian Research Data Archive. For easy reproducibility of figures shown in this work, all required data are contained within the data set, “Spatial SC and interannual variation in deposition of dust aerosols over the CLP” (Haugvaldstad et al., 2023). These data are meant to be used together with the AGU_JGR_CLP_SOURCE_WORKFLOW (Haugvaldstad, 2024a) workflow.…”