Drought And Storm Research Ordos Plateau Since The Ming Dynasty

Due to the arid climate, meteorological disasters such as the drought and wind disaster frequently occur in Ordos Plateau. Studying the drought and wind disasters not only has scientific significance to reveal occurrence regularity and characteristics of the disasters, but also has practical significance for disaster prevention and reduction. Through collecting the literature data since Ming Dynasty in Ordos Plateau, using the methods of literature data and statistics, this paper mainly analyzes the occurrence regularity and characteristics about the drought and wind disaster.Through studying the level, occurrence frequency, annual variation, seasonal variation and periodic variation, this paper obtains following conclusions:(1)The drought of Ordos Plateau was142times in Ming Dynasty,170times in Qing Dynasty,36times in the Republic of China,26times after1949. The drought events have occurred5times in Ordos Plateau since Ming Dynasty, respectively1580-1588,1631～1640,1711～1722,1929～1931and1960s.(2)From Ming Dynasty, the main drought is the moderate drought, secondly for the serious drought and the worst drought, the mild drought is comparatively uncommon. The main drought is spring drought and summer drought, The phenomenon of spring-summer drought often occurs. From Ming Dynasty, the drought is217times in south-east of Ordos Plateau,250times in south-west of Ordos Plateau,114times in north of Ordos Plateau. The south-west of Ordos Plateau is the most prone to drought from Ming Dynasty.(3)The drought of Ming Dynasty in Ordos Plateau had obvious periodic oscillations of0～6a,4～12a,8～20a,32～52a, The scale centers were about3a,8a,14a,42a, The first main period was about42a, The periodic oscillations in Qing Dynasty were3～5a,5～9a,20～30a,40～60a, The scale centers were about4a,7a,25a and50a, The first main period was about25a. The periodic oscillations in the Republic of China were4～8a,10～16a, The scale centers were about6a,13a, The first main period was about13a.(4)The wind disaster of Ordos Plateau was24times in Ming Dynasty,50times in Qing Dynasty,25times in the Republic of China.The peak period of wind disaster was Qing Dynasty and the Republic of China. Since Ming Dynasty, the wind events have occurred5times in Ordos Plateau, respectively1708～1710,1851～1853,1908～1910, 1878-1881and the1960s. When the climate turns to be cold or the climate is changeable, the wind disaster has high frequency.(5)From Ming Dynasty to1949, the main wind disaster was the moderate wind disaster, secondly for the mild drought and the serious drought in Ordos Plateau. The wind disasters mainly appeared in spring, secondly in winter, summer and autumn often had no wind disaster recordation. After1949, the gale days are22a,37d in south-east of Ordos Plateau,32a,84d in south-west of Ordos Plateau,30a,105d in north of Ordos Plateau. The north of Ordos Plateau is the most prone to wind disaster from Ming Dynasty.(6)The wind disaster of Ming Dynasty in Ordos Plateau had obvious periodic oscillations of3～9a,12～18a,22～40a, The scale centers were about6a,15a,31a, The first main period was about31a, The periodic oscillations in Qing Dynasty weree4-8a,16-30a, The scale centers were about6a,23a, The first main period was about23a. The periodic oscillations in the Republic of China were4～6a,10～18a, The scale centers were about5a,14a, The first main period was about14a.