Time Series Analysis Of The NOAA(AVHRR)NDVI In High Intensity Coal Mining Area Of ORDOS Based On SHENDONG Coalfield

Under the background of global change, it can not show that coal mining has no effect on surface ecology with the increasing of surface remote sensing biomass index(NDVI or NPP)in mining area;With manual intervention,the rapid growth of surface remote sensing biomass index in mining area is not the true expression of surface ecological process normal evolution in mining area.In this paper, SHENDONG coalfield is the directly affected area, at the same time the indirectly affected area(20km buffer) and natural ecological checked area are established. Using the long temporal series of GIMMS AVHRR/NDVI(1981.7-2006.12,26a) data, the above mentioned two areas and directly affected area are comparative researched with the phenological information. Data validation is done assisting by the long temporal series MODIS NPP/NDVI(2000-2010, 11a) data, and the consistent change results are got. It reveals the spatio-temporal coupling relationship between resource exploitation and ecological variation of vegetation and response characteristics of the mining intensity, climate change:1.Analysis of the spatio-temporal correlation indicates that under the background of the global warming,the extension of vegetation growing season in directly affected area leads to the increasing trend of AVHRR/NDVI in directly affected area,indirectly affected area and checked area; The average annual NDVI of 26 a in directly affected area,indirectly affected area and checked area are 0.2808, 0.2999 and 0.3252 respectively, the average annual NDVI in directly affected area is about 6.79% lower than that in indirectly affected area and about 15.81% lower than that in checked area.It indicates that coal mining has obvious effect on regional surface ecological process.2.Analysis of mining intensity correlation indicates that through piecewise linear regression analysis,the growth rate of NDVI in three regions is higher in undeveloped stage and the initial construction stage of the mine;During 12 years in the afternoon of development life, the growth rate of NDVI falls sharply,and the growth rate of NDVI is smaller with the larger mining intensity;In the afternoon of development life, the growth rate of NDVI in checked area is higher than that in directly affected area and indirectly affected area, and it has causal relationship between the decreasing growth rate of NDVIand mining intensity.3.Analysis of climate changes correlation indicates that the AVHRR/NDVI of 26 a in directly affected area,indirectly affected area and checked area is affected by the interaction of temperature and precipitation. The AVHRR/NDVI is increasing with the increasing temperature and decreasing precipitation.The correlation of maximum NDVI and temperature is high, the correlation of maximum NDVI and precipitation is low.The results show that it is an indisputable fact that mining has a significant impact on regional surface ecological process, and human activities interferes the evolution process of natural ecology in coalfield, climate changes have brought up the increasing NDVI in the whole area of NDVI increased, and mining leads to decreasing NDVI in directly affected area and indirectly affected area, the influence of mining on NDVI is much higher than the influence of climate changes on NDVI.