1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, Beijing 100038，China
2. China Institute of Water Resources and Hydropower Research, Beijing 100038，China
3. Research Center in Flood and Drought Disaster Reduction of Ministry of Water Resource, Beijing 100038，China
Abstract：Chlorophyll-a is a critical water quality parameter which can be used to evaluate the eutrophication degree of lakes. Remote sensing technology has the advantages of real-time, rapidity and wide monitoring range and has been widely used in inland lake water environment monitoring. Obtaining the chlorophyll-a concentration in lakes dynamically in real-time is significant for lake governance. The spectral characteristics of inland lakes are complex. So, it is difficult to accurately obtain the spectral characteristics of water bodies by multi-spectral remote sensing data. The Zhuhai-1 hyperspectral satellite has a broad application prospect in remote sensing monitoring of inland lakes because of its high spectral resolution and sufficient band. In this paper, the hyperspectral data of Zhuhai-1 is selected to retrieve the chlorophyll-a concentration in Chaohu Lake. First, extract the remote sensing reflectance curve at the measured point from the image, filter the bands with significant spectral characteristics according to the curve, and use the OIF index to measure the ability of different band combinations to obtain water body composition information. And finally build the band combination, which is highly correlated with the actual measurement chlorophyll-a concentration. The results show that the three-band model [Rrs(700 nm)-1-Rrs(670 nm)-1]×Rrs(746 nm) constructed by Zhuhai-1 in bands 14, 16 and 19 has achieved high accuracy in retrieving chlorophyll-a concentration in Lake Chaohu, the MRE is 19.97% and the RMSE is 10.85 mg·m-3, which is superior to most previous spaceborne remote sensing data sources. Retrieving the spatial distribution map of chlorophyll-a concentration of Chaohu Lake on May 10, 2019, shows that the chlorophyll-a concentration is increasing from east to west. The concentration of chlorophyll-a in the south and northeast of the lake is low, and the chlorophyll-a concentration in the north of West Chaohu The concentration of a reaches the highest concentration. The overall concentration of chlorophyll-a in West Chao Lake is the highest, especially in its northern waters, where the water quality is poor, and a certain bloom area has appeared. The main reason is that the area is close to Hefei City and is more susceptible to strong solid activities and large discharges of sewage and wastewater. The Zhuhai-1 hyperspectral satellite has certain advantages for the water quality retrieval of inland lakes, but it also has limitations such as difficulty in data processing, low band utilization, and poor universality of inversion models. It is necessary to use the Zhuhai-1 hyperspectral data to carry out more lake remote sensing research, continue to propose new methods of hyperspectral remote sensing image processing, and improve the accuracy and universality of the inversion model, fully tap the potential of the data source.
Key words：Hyperspectral remote sensing; Lake Chaohu; Chlorophyll-a; Remote sensing inversion; Zhuhai-1; OIF index
冯天时，庞治国，江 威. 基于珠海一号高光谱卫星的巢湖叶绿素a浓度反演[J]. 光谱学与光谱分析, 2022, 42(08): 2642-2648.
FENG Tian-shi, PANG Zhi-guo, JIANG Wei. Remote Sensing Retrieval of Chlorophyll-a Concentration in Lake Chaohu Based on Zhuhai-1 Hyperspectral Satellite. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(08): 2642-2648.
