Construction and Analysis of Severe Group Dust-storms in the Eastern Part of Northwest China

Based on the available original duststorms data from 60 meteorological observation stations, the paper constructed a quite complete series of severe group duststorms in the eastern part of Northwest China in 1954-2001. As a result, 99 severe group dust-storms have been found and confirmed in the eastern part of Northwest China in 1954-2001. Based on these 99 cases, the temporal and spatial distribution characteristics, especially inter-decade change of severe group duststorms were analyzed in the eastern part of Northwest China, and the following viewpoints were noted: (1) Alasan Plateau, most parts of Erdos Plateau and most parts of Hexi Corridor were the main area influenced by severe group duststorms, where there were generally more than 10 severe duststorms at some places and more than 20 events in some stations such as Minqin in Gansu Province in recent 48 years. (2) The major number of severe group duststorms is in spring, and the figure was 78.8%, especially in April there were 41 events and the figure was 41.4%. (3) The number of severe group dust-storms during the 1990s was 15, which is less than other decades. At the same time, the life cycle and the influencing area of severe group duststorms during the 1990s are shorter and smaller too. (4) In 2000 and 2001, there are 4 severe group duststroms broke out separately in the eastern part of Northwest China. It is the maximum after 1983.