内蒙古中部MODIS植被动态监测分析

对中分辨率成像光谱仪(MODIS)250m空间分辨率的每8天NDVI卫星遥感数据,利用年平均NDVI及一元线性回归方法,分析了2000-2008年内蒙古中部地区植被变化趋势。结果表明,近9年内蒙古中部地区79.60%地区的植被总体上保持稳定,17.33%的地区得到了明显改善,3.06%的地区仍存在较强的退化或沙化趋势。退化或沙化地区主要分布在内蒙古农牧交错带北部边缘,成条带状分布,反映了农牧交错带地区生态仍然较为脆弱,需要进一步关注和保护,东南部地区的植被恢复明显。植被年际动态主要受该地区暖干化气候影响,气候变暖造成植被NDVI增加,而降水波动导致NDVI随之变化,降水的作用是气温的2.8倍,有些地区可达到11倍之多。

Monitoring Inter-annual Vegetation Variation in Middle Inner Mongolia through MODIS NDVI

In this paper,we investigated the response of inter-annual vegetation variation to climate change in middle Inner Mongolia based on 250m MODIS NDVI data in 2000-2008 and climate data from meteorological stations during 1960-2008.After applying S-G filer process to deduct the noisy and abnormal points,the mean of 8-day NDVI in a year was calculated to indicate the vegetation status in that year.Then the trend of inter-annual vegetation variation in 2000-2008 was calculated with the linear regression coefficiency,that is the slope of a line,and analyzed through the regression significant level.The average NDVI by vegetation type was calculated according to vegetation map with a scale of 1：100 000.During the study period,79.60% of the vegetation area keeps a relatively steady state,and 17.33% changes to better.But 3.06% of the grassland is in degradation or desertification where is in the Farming-Pastoral Transitional Zone.The climate factors that caused inter-annual vegetation variance were quantified.The warmer and dryer climate change happened in this region was regarded as main reason.Between two climate factors of temperature and precipitation,the variance of precipitation has more effect on the change of NDVI than temperature.The ratio of standardized regression coefficients of precipitation and temperature is in range of 0.89（Suolun） to 11.50（Siziwang Qi）.At Xilinhot,the ratio is negative which may be explained as combined influence of unmatched temperature and precipitation.However,the inter-annual variance of grassland was affected not only by climate,but also by human activity.In this paper,however,the latter factor was not analyzed though it is very important for assessing the technique on ecosystem protection and recreation.Quantificationally assessing the effect of human activity under global climate change is an interesting and challenge research field for us in future.