Research On The Cause Of Formation And Forecast Method Of Draught In Inner Mongolian

This thesis, according to the needs of drought-resistant task in Inner Mongolia, has provided, through analysis and study of the following four aspects, the relevant information and technical support for the drought-resistant and reducing calamity tasks as well as for the command system of flood prevention and drought-resistance. First, through statistical analysis of the frequency, distribution of time and space and its intensity, continuous period and distribution of years etc of droughts in our region, the thesis has induced the basically properties of the drought in our region: universal existence; high frequency of occurrence; long continuous period; a higher frequency of drought in the west than in the east, in the pastoral areas than in agricultural areas; a large scale of drought influence and a serious condition of calamity; shortened period and worsening of droughts year in, year out and an obvious eastwardly stretching of arid areas. Second, through statistical analysis of such factors as nature which influences the droughts, the warming up of the climate, atmospheric circulation and society etc. the thesis has summed up the causes for the droughts: the special geographical location and natural climate conditions determining the fact that our region belongs to arid and semiarid areas; abnormal atmospheric circulation attributing to the main condition which leads to droughts; the warming up of climate making shortened period of droughts and worsening the droughts; social artifact factors influencing the process of land becoming arid. Third, according to the characteristic reflections of aridness by the crops and herbage, the thesis has selected precipitation factors, and worked out the quota for aridness with reference to timeness and affectivity of precipitation. Fourth, thought quantitative analysis of arid properties with the material chosen within the latest 30 years, the thesis has fixed a forecasting point and worked out four quantitative indexes witch help create an equation for the forecast of continues period of droughts. The equation, after having been used to test the continues forecasting droughts, proves being effective.