Research Of Vegetation Coverage Distribution Changes And Carbon Stocks Of Alpine Grassland Based On Remote Sensing Technology

Gannan Tibetan Autonomous Prefecture lies in the eastern part of Qinghai-tibet plateau; it has abundant resource of alpine grassland. But, they, together with a growing population in the urban area and in the animal husbandry industry, have made pastures in Gannan state long be jeopardized by overgrazing, estrepement, deforestation, biohazards and frequent natural disasters, etc, hence the severe desertification and grassland degradation in Gannan state. As Gannan is one of the main alpine pasturing areas in northern China, a lack of effective conservation and rational utilization of the resource of pastures have severely restricted the sound development of the regional characteristic economy of Gannan.Aiming at the afore-mentioned problems, this research selects Gannan state as the object. Based on the MODIS data and the remote sensing technology, this research reveals the dynamic change of the vegetation coverage of the area in recent ten years and the calculation method of the carbon stocks.Firstly, based on the dimidiate pixel model, this research has employed an improved vegetation coverage analysis model on the basis of NDVI vegetation index and has used the MODIS data MOD09A1and the spatial analysis function of3S technic (GIS, RS, GPS). The vegetation coverage of the alpine grassland of Gannan state from year2000to2010has been divided into five levels and calculated. The general evolution process and trend of the vegetation coverage of Gannan has been further studied. Secondly, with the MODIS data MOD11A2and biomass inversion model, the carbon stocks of Ganan state has been estimated, and the relationship between the vegetation coverage and the carbon stocks from year2000to2010has been analyzed.The results show that from year2000to2010, the rangeland vegetation coverage in Gannan deteriorates on the whole, and the degradation of first stage vegetation is most alarming. The change of grassland vegetation has indicates the trend of transform from high-stage (1st stage,2nd stage) to low-stage (4th stage,5th stage) vegetation coverage. Further analysis points out that, accompanying a constant change of the vegetation coverage area of all levels in Gannan state, the vegetation biomass experiences a restoration followed by rapid degradation, which has a connection with the management measures of cultivated pastures implemented from year2000to2005. Meanwhile, the leverage of carbon stocks of grassland in Gannan Tibetan Autonomous Prefecture generally declines. The result of carbon stocks calculation demonstrates that the model-based method accords with other related researches, and that the data of remote sensing technology are effective in estimating carbon stocks of grassland vegetation in a large area.The research informs the dynamic trend and the severity of the degradation of the grassland vegetation in Gannan area. Thereupon it provides valuable and effective references to related researches and rangeland management by government.