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Long-range transport of anthropogenic air pollutants from East Asia can affect the downwind marine air quality during spring and winter. Long-range transport of continental air pollutants and their interaction with sea salt aerosol (SSA) significantly modify the radiative forcing of marine aerosols and influence ocean biogeochemical cycling. Previous studies poorly characterize variations of aerosol particles along with air mass transport from the continental edge to the remote ocean. Here, the research ship R/V Dongfanghong 2 traveled from the eastern China seas (ECS) to the northwestern Pacific Ocean (NWPO) to understand what and how air pollutants were transported from the highly polluted continental air to clean marine air in spring. A transmission electron microscope (TEM) was used to find the long-range transported anthropogenic particles and the possible Cl-depletion phenomenon of SSA in marine air. Anthropogenic aerosols (e.g., sulfur (S)-rich, S-soot, S-metal/fly ash, organic matter (OM)-S, and OM coating particles) were identified and dramatically declined from 87 % to 8 % by number from the ECS to remote NWPO. For the SSA aging, 87 % of SSA particles in the ECS were identified as fully aged, while the proportion of fully aged SSA particles in the NWPO decreased to 29 %. Our results highlight that anthropogenic acidic gases in the troposphere (e.g., SO 2 , NO x , and volatile organic compounds) could be transported to remote marine air and exert a significant impact on aging of SSA particles in the NWPO. The study shows that anthropogenic particles and gases from East Asia significantly perturb different aerosol chemistry from coastal to remote marine air. More attention should be given to the modification of SSA particles in remote marine areas due to the influence of anthropogenic gaseous pollutants. [ABSTRACT FROM AUTHOR]

• A new internally-mixed aerosol optics scheme was developed. • Artificial neural networks were used to parameterize aerosol optical properties. • The inhomogeneous aerosol model had lower absorption than the well-mixed model. • The optics scheme was evaluated using the Weather Research and Forecasting model. • The impact of particle inhomogeneity was obvious in the planetary boundary layer. A new internally-mixed aerosol optics scheme was developed. Aerosols (organic carbon, sea salt, aerosol water, sulfate, and nitrate) were assumed to be internally mixed with black carbon and soil dust (BC and SD, respectively), both of which are treated as cores. In the SD-containing particles, the particle non-sphericity was incorporated. Aerosol optical properties were computed from the invariant imbedding T-matrix method and the Lorenz–Mie theory and then parameterized using a novel method involving artificial neural networks (ANN). The new scheme was evaluated using the Weather Research and Forecasting (WRF) model. A case study involving East Asia was performed on Dec 3-4, 2010. Compared to uniformly mixed aerosols, inhomogeneous mixed aerosols had lower absorbability and stronger solar backscattering, causing a positive aerosol direct radiative effect (DRE) bias at the surface (3.0 and 2.6 W/m2 for the Sichuan Basin and Northern China, respectively) and negative DRE bias at the top of atmosphere ([TOA], −3.5 and −2.2 W/m2, respectively). Inhomogeneity effects caused a large reduction (up to 0.2K) in the atmospheric warming above the planetary boundary layer (PBL) and caused a northerly anomaly at 850 hPa on the order of 0.3 m/s. The non-sphericity effect was only significant over the Tarim Basin. DREs related to non-sphericity decreased at both the surface and TOA (−1.0 and −0.6 W/m2, respectively) due to stronger extinction. Non-sphericity caused more surface dimming and more solar heating, which had opposite effects on temperature perturbation, producing a more obvious impact within the PBL than in the free atmosphere. [ABSTRACT FROM AUTHOR]

Knowledge of river sediment recycling provides important constraints on continent weathering and earth surface processes. In this study, we estimate the “comminution age” of sediments from the Changjiang (Yangtze River) and two small mountainous rivers in Taiwan based on their lithogenic ( 234 U/ 238 U) ratio. The ( 234 U/ 238 U) distributions in the Changjiang catchment are overall related to sediment grain size and chemical weathering regime, while ( 234 U/ 238 U) ratios in Taiwan rivers mainly depend on erosion/denudation processes. The comminution age constrains the time scale of sediment source-to-sink processes in catchments from sediment weathering/denudation to transportation, and finally deposition. Our results indicate that the comminution ages vary from 250 to 600 kyr for the Changjiang sediments and ~ 110 kyr for the Taiwan sediments. Different comminution ages are associated with contrasting erosion and weathering regimes and diverse topography between the large Changjiang catchment and small mountainous Taiwan basins. The longer comminution age of the Changjiang sediment is an interacting effect of a longer erosion/weathering history and sediment trapping effect (and thus slow transfer rate) created by broad floodplains and lakes in the middle and lower reaches. The shorter comminution age of the Taiwan sediment results from fast sediment denudation and transport associated with strong tectonic uplift, typhoon climate and steep topography. As these two major river systems dominate the sedimentology in East Asia continent margin, the distinct geological and topographical settings between the Changjiang and Taiwan river systems result in different sediment “source to sink” transport processes. This work presents a systematic and quantitative constraint on the time-scale of river sediment transfer process in East Asia, and also provides new insight into weathering regimes and sediment transport in monsoon climate-dominated continent and Island. [ABSTRACT FROM AUTHOR]