Study On Evaluation Of Ecological And Ecological Entropy Based On RS And GIS

With the development of economy and the over exploitation of resources,great changes have taken place in the ecological environment. In this situation,many scholars at home and abroad have carried out a large amount of research on the ecological environment from different angles. In these studies, the evaluation of the ecological environment is the basis and premise of ecological environmental issues. But at present, ecological quality evaluation was usually as the research content about the method and theory of ecological environment evaluation, the relationship among the internal ecological region as well as the influence degree was less concerned, the ecological environment evaluation needs further development.Panzhihua area has rich resources and frequent mining activities. After the setting up of Ertan hydropower station, there are many changes about ecological environment, both positive and negative. But ecological environment problem itself is an integrated system project involves people and ecology, hardware and software, protection and development, etc. Therefore, to learn and master the impact of human production and life by the ecological environment change in Panzhihua region, comprehensive analysis and evaluation of ecological environment is very necessary. The common evaluation methods and the theories tend to be single ecological evaluation for a particular area, rarely involves the internal analysis and the quantitative and qualitative research on the correlation of the ecological environment. Aiming at this problem, the concept and method of ecological entropy and entropy chain was put forward based on RS and GIS. Ecological network was established by geographic information network analysis method. Ecological security relations and influence degree was carried on through ecological chain. “Inflows” and “outflows” of ecological entropy value was expressed by “import” and “export”. Distance attenuation coefficient method was adopted to describe the attenuation law of ecological entropy value between the two centers. NDVI method was used to describe the attenuation of ecological safety entropy whose changes due to vegetation coverage changes. Import and export of ecological entropy theory is a technical means of analysis and evaluation of ecological environment, which play a significant role for a comprehensive evaluation of the ecological environment in Panzhihua area.The main research contents and achievements of this paper have several aspects as follows:(1)Firstly, the typical ecological index factor in the study area was analyzed based on remote sensing: such as land use types changes, landscape ecological index, vegetation coverage and NPP etc.(2)Remote sensing interpretation and remote sensing inversion were taking as calculating means. The social, cultural and economic data were assisted to filtrate ecological security evaluation factors: soil erosion, vegetation coverage, landscape index and the ecological elastic index etc. The pressure- state- response model was used to analyze ecological safety factor in Panzhihua area. After calculation and analysis, it turned out that vegetation coverage of Yanbian County and Miyi County has increased significantly and its ecological safety coefficient also has greatly improved during 1995 to 2010 in Panzhihua, but the ecological security of the East and the West is still not optimistic. Focus on the change of ecosystem health index before and after the construction of the Ertan hydro-power station, natural limiting factor(Net Primary Productivity, Surface Waviness, Water Resources Per Capita), human impact indicator(Population density, Human disturbance degree) and ecology health indicator(Vegetation Coverage, Regional Water Production, Biodiversity and Forest Coverage) etc. comprehensive index were used to obtain the Yalong river basin ecological health factor.(3)Directly or indirectly material and energy was provided to all kinds of human by ecological system, and which is the vital human natural capital. USLE model was used to calculate the soil erosion in the study area. According to the result, the soil loss overall showed a trend of increasing in Panzhihua region during 1995 to 2010. Based on that regional carbon storage is the sum of the ground carbon, underground carbon, the ground soil carbon, carbon storage was calculate from 1995 to 2010 in the study area, and then through comparative analysis, regional water rate was declined obviously. From the analysis of land use type, water yield more areas center on the forests, grassland and farmland, and was influenced strongly by rainfall. Water purification model using difference of nutrient remain as well as the output retained by each grid, calculate area spatial distribution characteristics of nitrogen and phosphorus nutrients. Watershed was used as evaluation unit, the output and keep quantity of N and P were analyzed and compared between 1995 and 2010. In general, ecological service value of carbon sequestration increased in research area, water rate service value has been declined, water purification service function has been reduced, soil erosion has been increased.(4)Aiming at the condition of the regional ecological environmental quality difference, this paper puts forward ecological entropy and the entropy concept of export and import creatively. Ecological entropy expresses the ecological stability within the regional ecological environmental quality. Entropy value of export and import express the regional ecological environmental impact.The source and end point of entropy in the ecological environment is described by the concept of node, center and obstacle in the GIS network analysis.By using this method, the ecological stability of each area in the ecological environment can be visualized.Based on this theory, the author calculated the ecological entropy flow and export coefficient in PanZhihua region.By the calculation, in 15 years, the west and east ecological entropy grows continuously and the ecological pressure is not optimistic. In addition, according to different research object, this paper adopted different evaluation unit and system. In view of the ecological health assessment of water system, the author used the watershed as the evaluation unit, but adopted county and township-level as evaluation unit in ecological entropy flow study. Analysis and evaluation from multi-angle and multi-level is also one of the characteristics of this article.(5) Ecology chain carries ecological entropy was put forward creatively. The method of ecology chain carries ecological entropy was adopted to analysis and study the ecological entropy change rule. The ecological entropy attenuation model was designed by water system, distance, and the NDVI as the attenuation coefficient. Among them, the farther the distance between the ecological centers, the smaller ecological entropy transfer; the larger of the vegetation coverage between ecological centers, the smaller the entropy values is; the farther the distance among watersheds along the river, the smaller ecological entropy is. Through adopting different chain expressing ecological migration of entropy, the influence degree was intuitive expressed between the ecological areas.Based on the knowledge of remote sensing, geographic information technology and ecology, the paper systematically evaluates the ecological environment quality of Panzhihua area by means of analyzing and studying the coupling and correlation between human and land and ecology. By means of network analysis, the correlation and influence degree of the two centers are expressed by the chain of the link center, and the evaluation unit is used as the center of the administrative region and the watershed center. The research methods of ecological entropy and ecological chain provide a new idea and method for the evaluation of ecological environment quality.