Remote sensing retrieval of secchi disk depth in Jiaozhou Bay using Sentinel-2 MSI image

In view of the current situation that the existing research of retrieval of secchi disk depth (SDD) was mostly based on lower resolution satellite data, the retrieval of secchi disk depth had been carried out using Sentinel-2 MSI image with a resolution of up to 10 m in Jiaozhou Bay. A retrieval model based on measured data was constructed. The results show that the retrieval model has high accuracy. The average relative error between the inversion value and the measured value is 9.86%, and the root mean square error is 0.22 m. Based on the constructed retrieval model and Sentinel-2 MSI image, the SDD in Jiaozhou Bay was inverted, the SDD distribution map was drawn, and the spatial distribution and local subtle change characteristics of the SDD in Jiaozhou Bay were analyzed. The study found that the SDD of Jiaozhou Bay showed a trend of gradually increasing from the coast to the sea. Rivers with large runoff caused changes that significantly reduce the SDD near the mouth of the river. The tide caused the texture change characteristics of SDD to appear along the direction perpendicular to the shore. The navigation of large vessels caused a short-term decrease of SDD.