Change Of NDVI And The Response To Climate In The Liaohe Basin

In this Paper, I researched ecological patterns and driving factors through analysis of change of NDVI and its response to climate factors in Liaohe River. The annual and interannual variations of NDVI and the relations between NDVI and climate factors were analyzed based on NOAA/AVHRR10day composite NDVI data from1982to1998, SPOT VEGETATION10day composite NDVI data from1999to2010and daily meteorological data at Thirty-four stations by using the average vale method, differencing, Linear regression of one variable and correlation analysis in Liaohe Basin.Main conclusions are as follows:1、The temperature increased significantly from1982to2010in Liaohe river basin, which was affected by global warming.The rate of annual average temperature was0.32℃/10a from1982to2010,0.32℃/10a from1982to1990, dropped to0.11℃/10a since2000.2、Vegetation status of the Liaohe Basin owns large local differences,improving from northwest to southeast. Relative rate of change of NDVI in part year in Liaohe River Basin is improving overall improvement of vegetation status by finding the region’s share of the proportion of vegetation improved better more than72%.3、Compared to NDVI rate of change from1982to1984, the area that vegetation cover reduced significantly reduced by16.15%from2008to2010in Liaohe River Basin, mainly distributed in area of temperate grassland and Cultivated plants. The season that NDVI increased significantly from1982to2010was summer, followed by the fall, winter at least. Autumn was keeping Vegetation Growth on summer.4、Vegetation cover of the Liaohe Basin trends to increase indistinctly as a whole during1982to2010with a linear regression trend of0.023/10a. Increasing trends of NDVI were same in area of Cultivated plants and temperate grassland, which is lower than temperate broad-leaved forest. Summer NDVI is not only the highest value of four seasons, but the fastest season with a regression trend of0.038/10a.5、Mean temperature in autumn and annual affected vegetation NDVI of Interannual changes significantly.The number of pixel that positive correlation significantly between NDVI in year and temperature in the same time, accounting for39.74%of the overall basin, mainly distributed in area of Cultivated plants and than temperate broad-leaved forest. Autumn NDVI and temperature performance over the same period a significant positive correlation, accounting for57.77%of the overall basin, widely distributed in the whole territory of the basin. Seasonal scales lag analysis showed that summer temperatures in autumn NDVI was significantly positively correlated, accounting for40.34%of the overall basin, mainly in the basin in south-central region, the data showed that summer temperature promote the vegetation growing season postponed.6、The role of changes in precipitation on the vegetation cover had not reached significant levels, the season NDVI response to precipitation did not appear to lag characteristics.NDVI of parts of downstream in the Liaohe River and precipitation performance over the same period a significant negative correlation, accounting for10.73%of the overall basin, mainly distributed in area of temperate grassland and temperate broad-leaved forest. Seasonal scales lag analysis showed that the precipitation in summer and autumn NDVI was significantly positively related, accounting for8.85%of the overall watershed, mainly distributed in Zhaluteqi、 Aluheerqing of Neimenggu and so on. Summer precipitation and winter NDVI was significantly negatively correlated, accounting for26.16%of the overall basin,mainly in distributed in Wengniuteqqi、Zhaluteqi、Balinzuoqi of Neimengu and so on.