The Study On Drought Diagnosis Analysis And Its Measures Of Major Grain Production Regions In Sanjiang Plain

Sanjiang Plain, as one of nine major commodity grain production regions in China, plays a decisive role in the food security. But drought appeared frequently in the non-traditional drought region since 2000, and the situation was becoming more and more serious.Even though the water conservancy facilities were improved constantly. Because of lacking systematic drought research in Sanjiang Plain, drought is the most important factor of agricultural reducing output. Therefore, it is essential to research drought scientific and rational for making strategy to anti-drought to protect Sanjiang Plain's sustained and stable development of national economy.(1)This paper introduce present drought related in Sanjiang Plain based on geographic and natural environment condition binding historical and real-time data. The authors took the annual precipitation of Hongxinglong Branch Bureau, in which 852 Farm of eastern, Beixing Farm of western and Jiangchuan Farm of middle, as the basic data, analyzed the multi-time scales variation characteristics with the application of a complex Morlet wavelet. At last, summarize drought cause according to analysis results and view of representative people.(2) According to principle of establishing evaluation index system, selected 3 indexes of departure ratio of rain-fall, Z index and homogenization of rain-temperature index as the basic index in this paper. The drought evaluation and analysis in Hongxinglong area are carried out, in which 852 Farm of eastern, Beixing Farm of western and Jiangchuan Farm of middle, and makes comparison between the results obtained through different indexes. The result indicates that the Z index serves a better way to analyze the drought.(3) This research established drought multiple-factors fuzzy comprehensive evaluation method based on the fuzzy mathematics theory, and then got the synthetic drought index system in Hongxinglong Branch Bureau area to analyze the drought condition of this area in 2008, in which 852 Farm of eastern, Beixing Farm of western and Jiangchuan Farm of middle, and achieved reasonable results. Results showed that the practicability was validated in this area.(4) The model of projection pursuit drought evaluation based on artificial fish swarm algorithm was proposed to optimize the function and seek the optimum projection for solving the problems such as the discrete evaluation grade and low resolved results obtained by using other methods. In order to avoid local optimization and improve the global search ability and the convergence speed of the algorithm, the adaptive artificial fish step and crowded degree factor were applied to optimize artificial fish swarm algorithm. The departure ratio of rain-fall, Z index and homogenization of rain-temperature were selected to establish evaluation model of Sanjiang Plain based on above methods. The results showed that model effectively avoided the incompatibility of single index. It was feasible to evaluate actual drought situation of this region, and provide a new way for drought evaluation.(5) The rainfall of the three farmswas forecasted by using the weighted Markov chain and grey system theory. The results showed that the forecast value of weighted Markov chain and grey system theory, and the actual value were tallied, and these methods have high feasibility used to precipitation prediction.(6)To adjust measures to local conditions to fight the drought. Combing with natural and geological conditions, agricultural planting structure, crop out put level, water resource exploitation and utilization degree and management ability about preventing drought and decreasing disaster, worked out countermeasure for drought and disaster accordingly.