Mapping the variation of Poyang Lake area based on multi-temporal MODIS imagery

The objective of this paper was to map the spatial and temporal variation of Poyang Lake area in ten years. To achieve this, in total, 460 scenes of 8-day composite images (500-m spatial resolution) during 2001-2010 from the MODIS sensor were used. To improve the accuracy in retrieving the temporal change of lake area, cloud contamination in each image was reduced by the Savitzky-Golay filter. Then, NDVI for each image was calculated and applied to retrieve the lake area by a threshold classification method. The probability of the spatial change of the lake area was calculated subsequently, and the map of the spatial variation of Poyang Lake area was produced, finally. The result showed that statistic on annual area of Poyang Lake had no significant variation during the period of 2001-2010. But the largest lake area was observed in 2010, which is 1397.17 km 2 , while the smallest was observed in 2004, which is 931.57 km 2 . For the seasonal variation of the lake area, the water level of Poyang Lake was highest in summer, while it was lowest in winter. According to the local investigation, the temporal and spatial variation of Poyang Lake could be attributed to the change of precipitation, irrigation, aquaculture and cultivation practices around the study area. However, it concluded that the multi temporal MODIS had advantages in monitoring the spatial and temporal change of lake area, as well as in monitoring the risk of flooding in similar large water areas.