Seasonal Pattern of Tidal-Flat Topography along the Jiangsu Middle Coast, China, Using HJ-1 Optical Images

摘要

Seasonal topographical changes in the intertidal zone are of high interest in many parts of the world. Due to existing challenges in mapping this dynamics, little is known about the seasonal pattern of tidal flats. This research aims to fill the knowledge gap by using optical images from the Chinese HJ-1 satellites constellation. A case study was conducted at the Jiangsu middle coast, a typical tidal flat region in China. Firstly, 455 optical images from the HJ-1 Satellites were collected to construct seasonal tidal flat Digital Elevation Models (DEMs). Next, synchronous Light Detection and Ranging (LiDAR) DEM and ground survey data were collected to validate the accuracy of the seasonal tidal flat DEMs. Finally, seasonal pattern of the tidal flats was demonstrated based on a time series of DEM volume comparison. The results show: (1) the HJ-1 images are qualified data source to produce satisfactory tidal flat DEMs with high spatio-temporal resolution and acceptable vertical accuracy. (2) In general, there are apparent erosion-and-deposition cycles in the Jiangsu middle coast, with deposition during the Winter and erosion during the Summer. Furthermore, the derived seasonal patterns differ notably among the five major sandbanks.