[Urban expansion and vegetation changes in Hangzhou Bay area using night-light data].

Based on DMSP/OLS night-light data and MODIS NDVI data for 2000, 2007 and 2013, this paper studied on characteristics of urban expansion and vegetation changes in built-up areas with nighttime light threshold extraction and vegetation index analysis using remote sensing and GIS. Results showed that the threshold method could realize the effective extraction of urban land information. In general, the urban built-up area expanded along with Hangzhou Bay in V model, and there were three expansion patterns: polygon pattern, linear pattern and point pattern. Obvious spatio-temporal variations in different cities were found in the rate and the dynamic degree of urban expansion and the compactness of urban morphology. The whole study area showed a decreasing trend in the rate and the dynamic degree of urban expansion, while the average compactness of urban morphology declined after the rise. Vegetation conditions became better in built-up areas except Jiaxing in 2000-2007, but it became worse in all cities in 2007-2013. Urban expansion had a ne-gative effect on the vegetation change in built-up areas in 2000-2013.