A study on assessment of urbanization and ecosystem changes based on MODIS time series in Shanghai municipality from 2000 to 2009

Shanghai is a metropolis with the fastest growing economy and the largest economic aggregate in China. In this paper, some change detection methods were used for assessment of urbanization and ecosystem changes. The urbanization area index (UAI) which is derived from land cover is used to reflect the speed of urban expansion, while the fraction of vegetation cover (FVC) which is retrieved from NDVI is used to represent the status of urban ecosystem. The NDVI time series were derived from MOD13Q1 by using an annual stacking approach. Land cover maps were retrieved from annual NDVI time series from 2000 to 2009. This paper focused on assessment study of urbanization level and ecosystem changes in Shanghai municipality. Results indicated following: 1) the urban area of Shanghai increased continuously in the past 10 years; 2) the UAI increased by an annual average rate more than 1.84%, its peak value was 4.36% during 2008-2009; 3) the urbanization degree of Shanghai ran on a high speed in the past decade; 4) on the whole, FVC decreased continuously over the past decade, while the FVC of urban area increased slightly and the FVC of some islands and outer suburbs increased slightly too; 5) the urban ecosystem of Shanghai became more and more "green" but at the cost of decreased cropland and natural vegetation cover. The assessment of urbanization and ecosystem changes suggests that suburban ecosystem protection is an import and urgent problem for government to implement more effective environmental management policies.