Study On The Spatial And Temporal EOS/MODIS VIs' Change In Hunan Province

As people's recognition go deep into the object world constantly, they find it is necessary to broaden the study scale to regional and even global extent. The Earth Observation System (EOS) system was put forward under such a background. So far, there are more than 20 satellites operating in their obits, which take many sensors with different temporal resolution, spatial resolution and spectral resolution, and the data generated from the sensors have made a great contribution to the study of atmosphere, ocean, biology and other dynamics and processes occurring on the surface of the earth. The Moderate-resolution Imaging Spectroradiometer (MODIS), installed both in Aqua and Terra, is one of these sensors, and it is a new optical instrument gathering high resolution and radiometric sensitivity features into one, so that its multi-channel data have two important characters: first, they provide many information about atmospheric (aerosol and cloud properties, water vapor and temperature profiles), oceanic (sea-surface temperature and chlorophyll), land-surface features (land-cover changes, land-surface temperature, snow cover, and vegetation properties); second, they have high temporal and spatial resolutions. Besides, its data can be easily obtained. Thus, they are widely used in geoscience study.Vegetation indexes (VIs) are spectral transformations of two or more bands designed to describe the quantity and quality of vegetation, and they can be an indication of vegetation growth and biomass. Study the varieties from VI time series can provide fundamental data for vegetation growth and distribution, phenology monitoring, affection of global change to vegetation covering, and monitoring and protecting of natural resources. Besides they can be scientific foundation for decision making.In this paper, MODIS VIs, namely normalized different vegetation index (NDVI) and enhanced vegetation index (EVI), are generated at 250m resolution every month in 2005 under the algorithm of maximum value composite (MVC). The procession of MODIS VIs composition is discussed in detail, including data selection, atmospheric correction, VIs calculation, getting rid of bowtie effect, geometric precision correction, the extraction...