| Qinling Mountains is the geographical boundaries of north and south in China and the transition zone between sub-tropical and warm temperate. This study selected the Qinling area located in Shaanxi province as a research object, and the research methods that Land Use and Land Cover Change of the Qinling area integrat remote sensing technique with GIS were designed by referring many literatures and many tests. This study analyzed spatial and temporal change of LUCC and the response of temperature, precipitation and runoff to environment on the basis of MODIS NDVI, TM images, DEM, temperature, precipitation and runoff data. The research has great significance to the quantitative study on ecological environment in Qinling area. The conclusion as follows:(1) AG (Asymmetric Gaussians) algorithm was selected to reconstruct the MODIS NDVI time series data. Spatial and temporal changes of Land Cover in Qinling area from2000to2011was analyzed by DEM, coefficient of variation, indication of the slope of trend line. Some results obationed:①the forest and shrub vegetation located in the hinterland of Qinling area showed a higher stability in the past12years, while the cropland and mosaic cropland/non-crop vegetation located in northern slope of the Qinling area, as well as those areas surrounded by mountain residents, showed dramatically inter-annual fluctuation under the impact of human activities.②the vegetation in the Qinling area, show and improved change trend in the past12years, and the arable land in mountainous hinterland and far away from the urban was improvement obviously.③NDVI change with elevation has the processes of first increases and then decreases in the Qinling area. The maximum value of NDVI located in the elevation of1500～2000m, while the minimum value located in the elevation of <500m, and the lower value of NDVI in the elevation of>2000m. In the elevation of1500-2000m and>2700m, NDVI increased trend was not obvious, while the increased trend was obviously in the other range of elevation. The rate of NDVI increased was decreased with elevation raised.(2) Based on the MODIS NDVI of250m resolution, TM images, and1:100000land use database, change vector analysis method and decision tree classification algorithms were used to analyzing the spatial and temporal change of Land Cover in Qinling area.①The analysis with change vector analysis methods show the high degree of land cover change with small area, nearby Taibai Mountain, Jialingjiang, Hanjiang, Danjiang, and Luohe river. Cultivated land and construction land have changed with high degree of land cover change, and smaller change area. The lower elevation area has the characteristic changes with lower degree of land cover change and bigger change area. Forest vegetation cover in the higher elevation area was stable. The area with stable land cover type in Qinling area accounted for79.99%, and with the increased trends, while the change area including increased and decreased area was mainly distributed in the valley of Jialingjiang basin, Danjiang, Luohe, and Hanjiang basin.②System of land cover classification and decision tree classification of land cover were constructed, and the overall accuracy was81.92%, Kappa coefficient was0.79. During2000-2010, land cover pattern analysis shows deciduous forest was increased continuously, while water area, grassland, arable land and unused land were decreased. The rate of decreased of arable land and grassland was increased. Building land increased quickly while evergreen forest first increased and then decreased.③In Qinling area, woodland, shrub and grassland area were stable, while water area and construction land increased, and cultivated land, unused land were decreased. In the different slope area, water area, cultivated land, construction land and unused land change obviously, while woodland and shrub only in the area of slope≥20℃were shown obvious change.(3) Temperature change characteristic in the annual and season and its effects on vegetation NDVI change were analyzed on the basis of monthly temperature and precipitation data from1970to2009, MODIS NDVI from2000to2009and DEM of30m resolution. Results show that average temperature in spring and winter were increased obviously and the abrupt change of temperature increased in1997,2000and1994, respectively. The rate of temperature increased in spring was higher than winter, and the spring and winter were higher than annual temperature. The response of vegetation NDVI to temperature analysis shows that the correlation between annual average NDVI and temperature was small (P<0.001), while the correlation between10years average NDVI and temperature was increased with the elevation increased, which reflected that, vegetation NDVI change in the higher elevation area was sensitive to climate change, and the area need to focus on. (4) Difference of runoff change between south and north slope in Qinling area and the response of runoff to precipitation and LUCC change were analyzed based on runoff data from1960to2009, meteorological data and MODIS NDVI data, in the selected typical basin of Jinqian river and Bahe river, located in the south and north slope area of Qinling area, respectively. During1960-2009, annual average runoff in Jinqian rivere and Bahe River showed decreased trends and the rate of decreased in Jinqian river was higher than Bahe River. Jinqian River was decreased obviously, while average runoff in spring and autumn of Bahe River was decreased obviously. The decreased of average runoff in the two basins was higher than annual average runoff. The analyzed in response of runoff to precipitation and LUCC change of Jinqian river show that, annual average runoff decreased was mainly by the influence of human activities, such as LUCC processes. The influence of human activities on average runoff in spring was bigger than autumn, while the decreased of average runoff in autumn was influenced by precipitation change and human activities. |
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