Detecting the spatiotemporal changes of tidal flood in the estuarine wetland by using MODIS time series data

This study was conducted to develop a novel technique of monitoring tidal floods and their spatiotemporal dynamics using a time series combination of the MODIS vegetation indices (VIs). The vegetation indices, which included the enhanced vegetation index (EVI), land surface water index (LSWI) and the difference in the values of EVI and LSWI (DVEL), were extracted from MODIS datasets with a spatial resolution of 500 m from 2001 to 2006. The technique first employed a wavelet-analysis to reduce the noise component of the time series of VIs, after which the smoothed time profiles were used to identify the spatiotemporal changes in tidal flood effects on estuarine wetland from islands to sea front. We found that combined application of EVI, LSWI and DVEL was suitable for monitoring flood inundation and recording flood dynamics and vegetation succession. Our approach takes advantage of both the flooded soils and canopy characteristics of vegetation during the tidal cycle and vegetation growth phases. The results of this study demonstrate the potential for the use of MODIS data for temporal and spatial detection of tidal flood effects in estuarine wetlands.