Analysis of flow regime in the turbidity maximum zone of Yangtze Estuary based on texture features of Tiangong-2 remote sensing images

Two regions in the South Passage of the turbidity maximum zone (TMZ) of the Yangtze Estuary were selected for an analysis of the flow regime by remote sensing images. The remote sensing images of these regions obtained by the wide-band imaging spectrometer in Tiangong-2 in the maximum flood during spring tide in the dry season and in flood season were processed by a Gabor filter to get the texture images on the ocean surface. The flow direction was extracted by visual interpretation, and the semi-quantitative flow regime information was obtained by calculation of the texture entropy in the images. The results show that the texture information in the remote sensing images processed by this method is abundant. The streamline is clear, which can clearly reflect the changes in the flow regime in different seasons. The texture features of these images reflect the variation in the flow regime around Nanhuizui after the construction of the reclamation project in 2014. Remote sensing images of Tiangong-2 are feasible in the semi-quantitative interpretation of the flow regime in the TMZ with high suspended sediment concentration (SSC) in the estuary.