The oasis regional small and medium lake water transparency monitoring research and impact factor analysis based on field data combined with high resolution GF-1 satellite data

Abstract

Water transparency is an important parameter to characterize water quality of rivers, lakes and wetlands. We measured the water quality data such as water transparency and the water spectral data of Shahu Lake. GF-1 image data were preprocessed to assure that the measured data were consistent with the reflectance curve of the remote sensing image data, and then selected an empirical method and semi-empirical/semi-analysis method of water transparency for remote sensing estimation of water transparency and constructed a remote sensing estimation model suitable for studying the water transparency of Shahu Lake. The new model was combined with GF-1 image data to analyze the total temporal and spatial variation characteristics of the water. The results showed that the empirical model based on the measured band 1/B4 of the spectral data was the best model for water transparency remote sensing estimation of Shahu Lake. The model was expression: SD = 0.3336 × (1/B1) + 27.94. The coefficient of determination of the verification model was 0.7454. The estimation of the water transparency model showed that the water in Shahu Lake has the transparency of the central lake and intake was higher and the transparency of the Third Drainage, Bird Island and Old Wharf were lower compared to each region. These findings were consistent with the measured numerical characteristics. The transparency of Shahu Lake is mainly affected by the water quality index, tourism activities, ecological hydration and distribution of reeds.