Coal Mining Influence On Grassland Greenness In Eastern China Using GIMMS NDVI 3g Timeseries Data

In this paper,the study area is located in the eastern China grassland with fragile cold,semi-arid,barren soil and other ecological vulnerabilities.In recent years,with the continuous expansion of the scale of energy base construction,regional eco-environmental pressure is also increasing.The eastern grassland area is an important large-scale coal and electricity base with open pit mining in China.Coal production capacity is more than 400 million tons,which provides the energy supply in northeastern China.Additionally,it causes groundwater degradation,soil and water damage,regional vegetation degradation and other ecological problems.Coal and electricity development and ecological protection is an increasingly prominent issue,and protecting the ecological environment is significant to whether energy bases can achieve sustainable development.The data show that,for China's open-pit coal mine,every 10,000 tons of coal mining,destroys a land area of 0.22 hm2,with an average annual damage to the land area of up to 10,000 hm2.Coal open-air and underground mining will also lead to coal-based aquifer water level decline.Administering effective measures to strengthen the ecological environment construction in this area is key to alleviate the ecological pressure and solve the environmental problems.Based on this,we used the GIMMS NDVI 3g dataset to study the spatial and temporal changes of vegetation greenness in the grassland of Inner Mongolia during the period of 1981 to 2010,to determine the relationship between the change of vegetation greenness and the development of coal mining in eastern China.We analyzed vegetation change tendency in Hulunbuir and Xilingol in the Inner Mongolia Plateau of China using the normalized differ-ence vegetation index(NDVI)time-series from the Global Inventory Modeling and Mapping Studies(GIMMS)Advanced Very High Resolution Radiometer(AVHRR)data set between 1981 and 2010.We used ordinary least squares(OLS)to analyse changes in grass-land greenness in Hulunbuir and Xilingol over 30 years.In the study area,we selected 24 coal mining areas,detected the changing trend of greenness in the mining area and their surrounding 10km,20km and 50km buffer zones,and analysed the correlation of NDVI be-tween the mining area and its corresponding buffer area.The research showed the following:(1)from 1981 to 2010,59.16%of the regional NDVI in growing season(GNDVI)had a decreasing trend in Hulunbuir,and 73.13%of the regional NDVI had a decreasing trend in Xilingol,which indicated that greenness generally decreased both in Hulunbuir and Xilingol;(2)in Hulunbuir,pixels that grassland vegetation greenness reduced located widely,and those increased located in the northeast;in Xilingol,pixels that grassland vegetation greenness reduced located in the east and southwest,and those increased in the northwest;(3)Both coal mining areas in Hulunbuir and Xilingol saw a decreasing trend in the greenness and Xilingol's trend was more obvious;(4)Both opencast mining and underground mining for coal have negative impact on greenness;(5)GNDVI can reflect land reclamation in mining areas.