Study On Comprehensive Divisions Of Drought In Liaoning Northwest

Drought is one of natural disasters which threat human society stability and development, extreme weather happened frequently that caused the trend of global drought more obviously and some area badly by Global change and human activities. Northwest of Liaoning belongs to Continental monsoon climate locating in Liaoning province. Because of the influence of geographical location, environment and natural climate, the frequency of arid area of Northwest Liaoning is high and serious causing large influence and loss. For the study of drought, Though domestic and foreign scholars have made many achievements, most are based on the purpose of atmosphere or agriculture and can’t reflect the comprehensive situation of drought roundly. Comparing with the method of variable fuzzy evaluation me and other comprehensive evaluation, it can reflect the comprehensive situation of drought neatly and objectively under the different model parameters. So this paper is based on variable fuzzy evaluation by changing parameter to reflect the drought about natural factors accurately and objectively, divide ranks by the arid situation of atmosphere and hydrology and analyze the characteristics of drought from time and space.The main research content is as follows:(1) To the 14 station’s 40 years long series of precipitation of Liao northwest, such as daily average temperature, daily maximum temperature, daily minimum temperature, wind speed, sunshine time, 2 m high daily meteorological, hydrological data and historical data, through reanalysis data selected the four indexes, according to the evaluation standard of each index have been identified, based on variable fuzzy evaluation method, compared with the subjective and objective comprehensive empowerment method and weight method to determinine the weight, under the different model parameters, the calculation has been caused by natural factors comprehensive evaluation class level of drought and drought.(2) According to the level of comprehensive drought characteristic value, mapped the northwest of Liaoning drought degree in each administrative unit annual variation trend chart, on the basis of variable fuzzy evaluation method is given for each administrative unit of the typical drought years. Fuxin ‘s peak and the more severe drought occurred in 1988 and 2001; During the three years in 2000-2000 in Chaoyang, the drought degree was concentrate and heavy, 2000 has reached close to droughts; Jinzhou, have also been more than moderate drought conditions in 1988 and 2000; With the data recorded in the historical data can be match well.(3) Based on the drought level characteristic value, this paper has carried on the time and space to northwest of Liaoning two dimensions analysis of the evolution law. On time scale range analyzed the degree of drought and drought of interannual change and trend. Spatial scales at all levels are analyzed spatial distribution characteristics of drought frequency. The frequency of mild to moderate drought is much lower in northwestern areas, the high-frequency region of moderate drought is located in Jianping and Lingyuan Suizhong of Huludao City and Chaoyang city-wide; severe drought is concentrated in the territory of Chaoyang, the occurrence of severe drought is not very high frequency relatively.Software support, Origin and Arcgis software.(4) Based on variable fuzzy evaluation method to get the characteristic values of comprehensive drought level combining with SPSS software, using empirical orthogonal function(EOF)(REOF) and rotated empirical orthogonal decomposition of Liaoning drought conditions in the region in northwest Liao. According to drought conditions in northwestern areas were divided, Ⅰarea is the more arid areas; Ⅱ area is arid areas and the level is in moderate drought; Ⅲ zones is almost between mild drought and drought in the dry zone; Ⅳ area is was light drought or not dry, making a more detailed and accurate description of the spatial distribution of drought conditions.(5) On the results of the analysis of this article, the Liao arid zone of northwest drought countermeasures with pertinence, meanwhile provide certain scientific basis to related departments to take feasible drought control and drought Suggestions.