The remote sensing dataset of offshore water quality includes three parameters: Dissolved Inorganic Nitrogen, Reactive Phosphate and Water Quality Classification. The unit of Dissolved Inorganic Nitrogen and Reactive Phosphate is mg/L. Water Quality Classification is dimensionless. The spatial resolution of wter quality parameters in this dataset is 300m, including monthly averaged nutrient concentrations and water quality classification results of the Guangdong-Hong Kong-Macao Greater Bay Area from January 2022 to December 2022. The measured data are from the Project 908 voyage in 2006-2007, which includes the measured spectral and nutrients. 30% of data were selected for independent verifications in modeling. Pixel points corresponding to the longitude and latitude of the inversion results of the corresponding date have been selected to match the measured data. Independent dataset validation correlation coefficients R2 are all above 0.9 and data points are distributed near the 1:1 line, among which Dissolved Inorganic Nitrogen validation R2 was 0.97 and RMSE was 0.002. The R2 and RMSE of Reactive Phosphate are 0.99 and 0.001 respectively. It shows that inversion results have some certain accuracy.
The nutrient inversion model of coastal waters of Guangdong, Hong Kong and Macao was constructed using Sentinel-3 series satellites with a spatial resolution of 300 meters. Based on the measured spectral and nutrient salt data, combined with Sentinel-III satellite secondary remote sensing reflectance products, the nutrient salt model of Guangdong, Hong Kong and Macao sea area was established based on methods including linear, interactive effect linear, support vector machine, Gaussian model, random tree, and etc. Data of Dissolved Inorganic Nitrogen and Reactive Phosphate in Guangdong, Hong Kong and Macao sea area were obtained by inversion. The water quality is then classified according to the national standard. Compared with these traditional navigation water quality parameter measurement methods, remote sensing repeated water quality parameters can provide water quality products with a higher spatiotemporal resolution and a larger observation range. Remote sensing datasets of offshore water quality parameters can provide a strong guarantee for monitoring water quality changes in the Guangdong-Hong Kong-Macao Greater Bay Area.
