Remote Sensing Analysis For Changes Of Lakes Of Tibetan Plateau In Recent 40 Years

Lakes are sensitive to climate and environment change.Meanwhile,climate change have a huge impact on lake area.The Tibetan Plateau is the largest number of lakes in the largest area of the plateau lakes,less affected by human factors.So it is more sensitive to climate response.This study selected the Tibetan Plateau as the research area,divided into 12 basins for research.Using GF-1 satellite 16m resolution multi-spectral image to extract area of lakes which is more than 1 km~2 and analyze the causes of lake changes in Tibetan Plateau from 1975 to 2014 combined with the data of lakes of Tibetan Plateau from Lake Survey of whole country.The results show that:(1)Image data based on the extraction of 2014 Qinghai Tibet Plateau above1km~2,respectively,using visual interpretation method.NDWI water index method and object oriented method to extract,NDWI extraction accuracy is relatively low,and object-oriented extraction method with high precision.After water shadow volume index and artificial correction,the extraction accuracy further improved.(2)The method of determining the optimal scale in the object segmentation method is proposed,which solves the problem that the former can only be used to determine the scale of object segmentation.(3)Analysis of lake change trends in 1975~2014,the number of lakes in the Qinghai Tibet Plateau showed a first increase and then decreased.The total area of the lake showed a continuous expansion.The Brahmaputra Basin's Lake area continued to show a downward trend due to the evaporation increase.The source of the Yellow basin change first atrophy after expansion because precipitation area.The Inner basin due to the elevated temperature reduction and precipitation increases.The amount of evaporation from the glacier melt in Lake area continued to expand.