| The sand-dust weather is a kind of disaster weather which happens frequently in the arid and semi-arid areas of China, in recent years(2000-2002), the frequency of sand-dust weather increased year by year. The severe sand dust not only has great effects on the quality of atmosphere environment in cities and on people's health, but also can be transported by northwest current to the sea, and exert baneful effects on marine ecosystem.In this paper, based on the Micaps meteorology data during 2000 - 2002 provided by China Weather Bureau, the routine observation data from March to May in Sand-dust weather provided by Qingdao Weather Bureau, and EP/Toms satellite observation data, the dry deposition of sand aerosol data from February 2002 to February 2003 in Beijing and from may 2001 to December 2001 in Qingdao, author analyzed the processes about source, transportation and deposition on the sea in East Asia in recent years. In addition , the cases about severe dust storm on March, 20, 2002 and the sand-dust weather in Qingdao were analyzed.According to the source areas, the sand-dust storms are classified into two types: the inner source and the outer source sand-dust storms. More than half of the sand-dust storms affected China came from Mongolia. Analyzed the source areas of dust aerosol, author found that the source moves to the east gradually year by year from 2000-2002. In recent years, the source areas of Asian dust are mainly located in the deserts in Inner Mongolia, Xinjiang and Loess altiplano . Loess altiplano is the mainly enhanced source of dust aerosols, which effect on the north China Plain, and the middle and lower reaches of Changjiang River. In southern Xinjiang basin, sand-dust storms occur most frequently in spring, especially in April, in the Taklimakan desert and it's surrounding areas.More than half of the sand-dust storm from the northwest China are found to be distributed widely in the north part of China and transported long distance to the sea. The probability of dust aerosols deposition flux to the Bohai and the Yellow sea is more than that of the East China Sea, and the deposition flux to the South China Sea is the least. Dry deposition flux to the Yellow Sea is about 5.18m"Y'. Generally speaking, there are three tracks of dust aerosols to the sea: firstly sand-dust storms which occurred in Mongolia intruded into China from Erlianhaote, a city in the northern part of inner Mongolia and across Hunshandake desert and Keerqin dene,then were deposited into the Bohai and Yellow Sea, secondly Sand-dust storms which occurred in the east of Xinjiang and west of Inner Mongolia were transported from west to east, and then sunk into the Bohai, the Yellow Sea and the East China Sea, and thirdly sand-dust storm occurred in the northwest of China might be transported by the high northwest current and sunk into the Yellow Sea, the East China Sea or the West Pacific Ocean.A strong sand-dust storm weather process occurred on March 20, 2002 is analyzed. The results show that the event was caused by the Mongolia cyclonic eddy and the northwest strong cold air. The persistence of dry warmer sector in winter in northwest of China is the index of its occurrence. Moreover, the sand over the ground surface also provided a favorable substance condition. Sand-dust weather in Qingdao occurred frequently in spring. Dust aerosols in Qingdao come from three area: the desert in west of Inner Mongolia and the dene in east of Inner Mongolia together with Loess altiplano. The northwest track and the north track are two movement routines of dust aerosols which intrude Qingdao coastal areas, and occurrence of the northwest track is a little more than that of north track. |
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