Long-range transport of spring dust storms in Inner Mongolia and impact on the China seas

Analysis of daily observations from 43 meteorological stations in the Inner Mongolia Autonomous Region, China, showed the distribution of spring dust storm events during 2000–2007. Guaizihu and Sunitezuoqi stations had the highest frequencies of dust storms. The interannual and seasonal variations of dust storms were closely related to weather conditions, especially the wind speed. A forward trajectory model and satellite observations were used to investigate the transport paths and dust layers of dust storms from Guaizihu and Sunitezuoqi stations to the China seas and their probability of influencing the seas during spring 2000–2007. Forward trajectories showed that dust storms at Guaizihu and Sunitezuoqi stations had the highest probability of affecting the Yellow Sea, followed by the Bohai Sea, the East China Sea, and the northern South China Sea. The dust particles from Sunitezuoqi station affected these four seas directly through coastal areas, while those from Guaizihu station were transported via the Inner Mongolian deserts and/or the Loess Plateau. The dust storms from Sunitezuoqi station impacting the four seas were characterized by a single dust source and a short transport distance, while those from Guaizihu station were characterized by multiple sources and relatively long transport distances. The dust particles from these two stations were mostly transported in a <4 km layer from the source regions to the seas. The satellite vertical profile also indicated that dust particles were mainly contained in a 0–4 km layer over the source regions and the four seas. An aerosol index retrieved from satellite observations and the estimated dust deposition also supported the influence derived from the forward trajectory model, with large aerosol index and dust deposition values occurring on the dust days affecting the four seas. The average deposition over the four seas was 18.7 g m−2 during spring 2000–2007.