Monitoring And Evaluation Of Net Primary Productivity Change In Coal Mine Based On Remote Sensing

Mineral resources exploitation plays an irreplaceable role in national economic development, however it also causes severe damage to mine ecosystem and eco-environment threat to ecological security, economic development and social progress. The multi-disciplinary theoretical knowledges are introduced into this study which is to monitor and evaluat ecological disturbances in mining area based on the indicator of Net Primary Productivity .Firstly, the dissertation analyzed the phenomena of mining ecosystem disturbance from its influencing factors, characteristics, forms. It took Jiuli mining area of Xuzhou as an example and analyzed the response mechanism of biological factors, abiotic factors, landscape factors of mining ecosystem disturbance from the following four aspects: the mechanism, factors, evaluation, response characteristics of mining ecosystem disturbance.Secondly, according to the objective and content of mining ecosystem disturbance monitoring, it analyzed the practicability and rationality of taking NPP as the index of mine ecosystem disturbance monitoring. Based on RS and physiological ecology, it established the model of NPP in mining area--an advanced CASA model. The model was improved in the following three aspects: (1) Through the combination of RS data and experimental data, it established inverse model of FPAR and vegetation coverage f to ameliorate effective radiation parameter of photosynthesis absorbed by plant; (2) It proposed a determination method of NDVI parameter by frequency diagram to improve the estimation precision since NDVI is the key parameter of the model; (3) It improved the precision of the basic data. Image spatial resolution was 30m,and the maximum light utilization efficiency was improved by the different land cover type and numeric,so the precision of the land cover classification was improved..Thirdly, it established the evaluation system of mine ecosystem disturbance monitoring based on NPP, adopted the traditional monitoring technology, RS and GIS to get ecological information of mining ecological disturbances, adopted ameliorated CASA model to evaluate NPP in mining area. The model was reasonable after verification. The evaluation analysis indicated: (1) According to the analysis of NPP temporal and spatial variation in different years to the studied area, the simulation value of NPP decreased continuously from 1987 to 2008. The peak proportion of NPP variation decreased gradually, and the range of peak increased gradually and the variation trend became gentle. It meant that mining had much more influence on vegetation productivity. The average variable quantity of NPP in the ecological damage area is from 2.752 gCm-2month-1 to 4.752 gCm-2month-1.The average variable quantity of NPP in the ecological influencing area is from 0.152 gCm-2month-1 to 0.352 gCm-2month-1.The average variable quantity in the ecological damage area was greater than the ecological influence area; (2) The analysis of NPP variation in different land cover type indicated that NPP in mining area decreased continuously from 1987 to 2008, and the average decreasing amount of NPP was 5.531 gCmonth-1, and the decreasing amount of farmland and woodland was the greatest. The farmland decreased 6.785 gCmonth-1, and the woodland decreased 10.056 gCmonth-1. It was the most direct reason that led NPP decreased. The variation trend of NPP was consistent with land cover area variation; (3) The analysis of NPP variation in different mining area type indicated that along with the plant capacity expansion of mining area the bigger decreasing amount of NPP was, the worse the ecological destructiveness around the mining area was. NPP began to decrease in the construction period of mine ,and then NPP reduced markedly in the high stable production period of mine,and subsequently NPP had the increasing trend during the decay period of mine. (4) The variation analysis of influencing factors indicated that NPP variation in mining area was dominated by the mining activities, and NPP was sensitive to the mining activities. The influencing range of NPP by the climatic change was from 0.1105 gCm-2month-1 to 3.3325 gCm-2month-1, and the influencing range of NPP by mining activities was from 90.5253 gCm-2month-1 to 107.8915 gCm-2month-1; (5) The interaction analysis of factors affecting NPP indicated that the climate change and the mining activities interacted on the variation of NPP, and the climate change pushed NPP to forward direction and the mining activities pushed NPP to negative direction. Along with the enhancement of mining activities, the mining activities became the leading factor that influenced NPP and the ratio of negative direction increased.Finally the dissertation developed a mining ecological disturbance monitoring system based on NPP and presented its application and suggestions.