Regional characteristics of dust storms in China

Regional characteristics of dust storms in northern China are analyzed using a rotated empirical orthogonal function (REOF), based on the annual days of dust storms from 1954 to 1998. The relationships between regional dust storms corresponding to other factors such as precipitation and temperature are explored. The results show that five leading modes of dust storms exist in the following areas: the Taklamakan Desert (Tarim Basin) over the Xinjiang region (far northwestern China), the eastern part of Inner Mongolia (North China), the Tsaidam Basin, the Tibetan Plateau, and the upper reaches of the Yellow River (Gobi Desert). These areas are associated with an arid climate and frequent winds. For the first mode in the Tarim Basin, most dust storms appear in the 1980s, while dust storms become less frequent in the 1990s. The second mode (North China) shows the highest frequency of dust storms in the mid-1960s but the frequency decreases afterward. The third mode indicates a decreasing trend of annual dust storms after the mid-1960s but with a high interannual variability. The fourth mode also shows a decreasing trend but with a low interannual variability. The fifth mode displays a high frequency of dust storms in the 1970s followed by a decreasing trend. For the five moles of dust storm distribution, four of the centers are located in desert regions. The annual dust storms of a selected station in each mode region are shown to compare the coefficient time series of these modes. The negative correlation between the prior winter temperature and dust storm frequency is identified for most stations. There is no consistency in the correlation between the dust storm frequency and the annual rainfall as well as the prior winter rainfall at these stations. The activity of dust storms in northern China are directly linked to the cyclone activity, especially for the interdecadal variability. (C) 2004 Elsevier Ltd. All rights reserved.