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Abstract Mineral dust aerosols can substantially influence the Earth's climate by altering the radiation budget and modifying cloud microphysical and radiative properties. Through long-range transport, dust aerosols could have a global impact. Here, using a fully coupled meteorology-chemistry model (WRF-Chem) and the tracer-tagging technique, we conduct quasi-global simulations to investigate the characteristics of dust intercontinental transport in the Northern Hemisphere and the source contributions to dust outflow from East Asia. Model results show that total dust emission from the main deserts (i.e., North Africa desert (NFD), Middle East desert (MED) and East Asia desert (EAD)) is about 4531 Tg yr−1, in which 66% is from NFD, 24% is from MED and 10% is from EAD. During long-range transport, the NFD and MED dust plumes are separated into two branches by the Tibetan Plateau, with higher dust concentration of 4 μg m−3 in the northern branch (37° N-60° N). The imported dust mass from NFD and MED to East Asia is 16.0 Tg yr−1 and 33.8 Tg yr−1, respectively; the local dust mass emitted from EAD can circumnavigate and import about 0.41 Tg yr−1 of dust into East Asia. As part of the "Asian outflow", the MED and NFD dust is transported above 600 hPa with concentration of 2 μg m−3, while the EAD dust is mainly transported below 600 hPa with concentration of 3 μg m−3. The total outflow dust mass from East Asia is 12.0, 9.7 and 7.7 Tg yr−1 from EAD, NFD and MED, respectively. Dust particles dominate the aerosol mass concentration with a fraction of 56.5% in southern East Asia and 75.4% in northern East Asia. Moreover, dust number from EAD dominates the total aerosol number north of 37oN below 600 hPa, with a size range of 0.156–0.625 μm, but the NFD dust number is mainly above 600 hPa. MED dust number dominates the total column aerosol number south of 37 oN, with a size range of 0.312–0.625 μm. Quantifying dust source contributions and the associated dust number loading and size distribution over East Asia is important for understanding the role of East Asian dust outflow in climate and hydrological cycle. Highlight • Investigating the intercontinental transport characteristics of dust from different sources. • Estimating the dust mass flux import into and outflow East Asia. • Quantifying the source contributions of dust outflow from East Asia. • Quantitatively describing dust number loading and size distribution over East Asia. [ABSTRACT FROM AUTHOR]

Abstract To quantitatively estimate the divergences in the natural and anthropogenic dust emission fluxes among different climatic regions, the total dust emissions at the global scale from 2007 to 2010 were simulated in this study. Despite the widely scattered anthropogenic dust distribution, the total area of potential anthropogenic dust sources was found slightly higher than that of natural dust sources. The anthropogenic dust distribution area was 1.61 × 107 km2 in January and 1.54 × 107 km2 in July, respectively. The natural dust sources contributed 81.0% of the global dust emissions and the anthropogenic contributed 19.0% of the residual. The natural and anthropogenic dust emission flux was 6.34 ± 0.31 μg m−2 s−1 and 1.01 ± 0.07 μg m−2 s−1, respectively. Especially, natural and anthropogenic dust emissions situated in different climatic regions. Natural dust emissions mainly located in hyper-arid and arid regions such as the Sahara, Arabian and Taklimakan Desert where dust emission fluxes range from 1 to 50 μg m−2 s−1, accounted for 97.3% of natural dust emissions at the global scale. While anthropogenic dust emissions concentrate in semi-arid, sub-humid and humid regions and generally fluctuated between 0.1 and 10 μg m−2 s−1. In addition, natural and anthropogenic dust proportions in semi-arid regions were the most complicated due to the complex land cover types, including grasslands, urban areas, croplands and open shrub lands, resulting in 42.99% of the anthropogenic dust emissions in semi-arid regions. The complex interplay of natural and anthropogenic dust emissions contributing to the total dust loadings may be a crucial factor enhanced the warming over semi-arid regions. This study provided confidence for the further investigation of the climatic impacts of natural and anthropogenic dust in different climatic regions under the background of global warming, especially the strengthening warming in semi-arid regions. Highlights • Quantitatively estimating indirect and direct anthropogenic dust emission. • Investigating the natural and anthropogenic dust emission among climatic regions. • Anthropogenic dust sources scattered but their total area larger than the natural. • Natural and anthropogenic dust in semi-arid regions complicated by land cover types. • Providing confidence for the research in climatic impacts of anthropogenic dust. [ABSTRACT FROM AUTHOR]

An intense summer dust storm over East Asia during June 24–27, 2010, was systematically analyzed based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captures the spatial and temporal distributions of meteorological factors and dust aerosol in summer over East Asia well. This summer dust storm is initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air is transported southward and further enhanced by the narrow valleys of the Altai and Tianshan Mountains, which results in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD areas are high as 54 µg m −2 s −1 on June 25. The dust aerosol from the TD then sweeps across Inner Mongolia, Ningxia and Mongolia, and some are also transported eastward to Beijing, Tianjin, Hebei, and even South Korea and Japan. The simulations further show that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heats the atmosphere at a maximum heating rate of 0.14 K day −1 , effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The average direct radiative forcing induced by dust particles over the TD at all-sky is −6.0, −16.8 and 10.8 W m −2 at the top of the atmosphere, the surface, and in the atmosphere, respectively. The discussion about radiative forcing induced by summer dust provides confidence for future investigation of summer dust impact on cloud properties and precipitation efficiency in the eastern China. [ABSTRACT FROM AUTHOR]