GIS-Based Drought Degree Stady In Gannan Area In Heilongjiang Province

Drought and water shortage is a major global facing issue in recent years. In the next 50 years, the shortage of water resources will become more and more acute contradiction in northern China region. Drought is the most important factor of global agricultural reducing output. Agriculture is the basis for the country sustained and stable development. So studies of drought and Withstand drought risk to the protection of China's sustained and stable development of national economy as a whole is essential. The first thing we must do is a scientific and rational drought analysis for solving problems of drought, and then we can make rational and effective strategies.This Paper established dry indexes system in the drought and half drought regions of Gannan. The paper mainly analyzed rainfall, evaporation, soil moisture, applied the fuzzy synthetic evaluating model into drought evaluation and exploit the GIS systems. Main results are as follows:(1)On the basis of procedures, methods and principles of evaluation index system established agricultural drought evaluation index system in Gannan area. Tinking of the actual situation of Gannan area, so selecting rainfall, evaporation and soil moisture as agricultural drought index.(2)To establish the fuzzy synthetic evaluating model, using of the fuzzy relation principle, the model made rainfall, evaporation and soil moisture to evaluating intangibly. Firstly,from the perspective of single factor evaluat the drought degree. Then consider of different importance of indexes and find out the result. Using this model evaluated the situation of drought in Gannan area in 2001. The result is consistent with the actual situation, so the model is practical in Gannan area.(3) To develop GIS system, established a database of drought information of Gannan area. To introduce GIS into dry index evaluation system can combine figures with datum expediently and adequately in order to express datum with geological figures' information adequately. The system can query and evaluate Gannan area' information.(4)According to the actual situation of Gannan area, established the model of grain loss in Gannan area by expected value. It makes an assessment for the losses of drought in Gannan area in few years.(5)To adjust measures to local conditions to fight the drought. Combining 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.