The Study Of Sustainable Degree Model Based On Regional P-R-E-D System——Exemplify With Minfeng County

The study on regional P-R-E-D system takes the coordinated growth of population, resources, environment and development梩he four subsystems of its?as its objective. Such research begins in seventies last century, only developing thirty years up to now. It begins with qualitative description by index system and now many experts make an attempt on the quantitative evaluation. Generally, during the course of study on regional P-R-E-D system, it will be more scientific and objective to put the quantitative means into use unquestionably, but till now, the qualitative description is still in the dominant position, mainly due to the late starting.Conforming to the trend of quantitative research, many experts in our country try to study the regional P-R-E-D system with quantitative method and have made some progress. Among the limited evaluation models, the one of sustainable degree lays stress on the key characteristic indices, and choos~the most critical one to construct model. It defines six factors to appraise the sustainable degree. That is economic development, development stage, energy consumption, population growth and environment quality. It is comparatively more reasonable and feasible to evaluate industrial cities. Owing to the vast territory ~nd complicated constitution, the key factor making the environment fragile or deteriorated varies greatly in China, which determines that the indices should be different. Therefore, the result evaluated by the environment quality factor is deficiency in applying in different regions. However, it can be used more widely if improved.The dissertation discusses how to improve the sustainable degree model to make it appropriate for being applied in Xinjiang. The author chooses Minfeng county as research region to testify the improved model based on the concrete process.1 .Determining the evaluating indices: Based on the unique regional environment of Xinjiang, the author determines two kinds of evaluating indices: one for sustainable degree, the other for ecological factor. Emphasizing on later and selecting the indices as: annual temperature, annual precipitation, days of annual sandstorm and cultivated area.2.lmproving the model: According to actual circumstance in Xinjiang, the author improves the model to:= (1梣)x(M/M0)x(G/G0)qx (N/No)x el/JoIII-~/Let S be for the sustainable degree,Let q be the Engel coefficient,Let M be the total amount of water resources in evaluating year,Let M0 be the total amount of water resources in preference year,Let G be the gross national product in evaluating year,Let G0 be the gross national product in reference year,Let N be the population in evaluating year,Let N0 be the population in reference year,Let I be the level of ecological environment in evaluating year,Let I,~ be the level of ecological environment in reference year.3.Choosing the research region and assigning the indices: Thinking it over, the author chooses Minfeng county as research region, then assigns the indices, standardizes the ecological environment indices, and determines its weight in the light of experts?suggestion.4.Applying the model and gaining the result: Putting the indices into the model, gaining the fluctuating curve of synthetic sustainable degree and analyzing its trend, which indicates that during the evaluating period, the trend of synthetic sustainable degree declines a little on the whole. From 1986 to 1989, the sustainable degree increase continuously, mainly thanks to the prosperous developing of national economy. From 1989 to 1997, the curve of sustainable degree oscillates greatly. In the prophase, it is the large decrease of water resources that causes the severe dropping of the curve. From1997 to 1999, the sustainable degree rises on the end.5.Contrasting and analyzing: Contrasting among different estimating results for sustainable degree based on variety ecological environment factors to testify the feasibility of the...