Water monitoring of the Weihe, Jinghe and Bahe rivers surrounding Lantian County and Jingyang County, Shaanxi Province

Monitoring the water environment of rivers and lakes has always been a highly valued issue for humankind. Compared with traditional monitoring methods, satellite remote sensing technology has the characteristics of being macroscopic, efficient, and economical, and has significant advantages in obtaining long-term, large-scale spatiotemporal changes in the water environment of rivers and lakes, and has been widely used in many fields.

Hyperspectral water monitoring principle

Hyperspectral technology is a sophisticated technique that can capture and analyze the spectral information of objects with high spatial and spectral resolution. By acquiring point-by-point spectral data of objects, hyperspectral technology can detect the unique spectral "features" of objects at different locations. Since each substance has unique absorption, reflection, and scattering properties at different wavelengths, hyperspectral technology can detect and distinguish substances by analyzing these spectral features.
Therefore, compared to traditional remote sensing imaging techniques, hyperspectral technology can provide richer and more detailed spectral information, enabling the differentiation of substances that are visually indistinguishable. By analyzing and processing large amounts of spectral data, it can be used to identify and analyze water bodies.

Application of hyperspectral technology in water monitoring

Hyperspectral technology has a wide range of applications in water quality monitoring, providing detailed water quality information and more comprehensive water body analysis.
1. Water quality parameter estimation: Hyperspectral technology can infer the concentration of water quality parameters, such as suspended solids concentration, chlorophyll content, and dissolved organic matter concentration, by analyzing the spectral characteristics of water bodies.
2. Water body classification: Different types of water bodies have different spectral characteristics. Hyperspectral technology can identify and distinguish different types of water bodies, such as rivers, lakes, and oceans, by analyzing spectral data.
3. Water Pollutant Monitoring: Hyperspectral technology can be used to monitor pollutants in water bodies, such as heavy metals, organic matter, and suspended solids. Different pollutants have unique absorption or reflection characteristics in their spectra, and the presence and concentration of pollutants can be detected by analyzing spectral data.
4. Algal Bloom Monitoring: Hyperspectral technology can detect algal blooms in water bodies. Algae contain chlorophyll, and their specific spectral characteristics can be captured and analyzed by hyperspectral technology, thereby enabling the monitoring and early warning of algal blooms.
5. Water transparency and turbidity: By analyzing the reflection and scattering characteristics in hyperspectral data, the transparency and turbidity of water bodies can be inferred. These parameters are crucial for assessing the clarity and turbidity of water bodies.

Water monitoring project introduction

Xi'an, located in the geographical center of China, has been known since ancient times as "Chang'an surrounded by eight rivers." These eight rivers—the Wei, Jing, Feng, Lao, Yu, Hao, Chan, and Ba—flow around the city of Xi'an and are all part of the Yellow River system. This time, the Xi'an Aerospace team from the Chinese Academy of Sciences used hyperspectral remote sensing technology to monitor the water bodies of the Wei, Jing, and Ba rivers surrounding Lantian and Jingyang counties in Shaanxi Province and extracted relevant information.

Water color index

The water color index is generally related to the chlorophyll content or other suspended matter concentration in a water body and can reflect the nutrient status or algal growth of the water. The water color index in this area includes a high value (High: 1.36) and a low value (Low: 0.21), indicating that there may be some water pollution or nutrient overload in this area.

Water transparency

Water transparency is an indicator of water clarity; higher transparency generally means clearer water. High transparency values ​​indicate that certain areas of water are relatively clear, while low values ​​indicate relatively turbid areas.

Today, the application of hyperspectral technology in water quality monitoring can provide more accurate and comprehensive water quality information, helping to understand the quality of water bodies, pollution status, and the health of ecosystems. Through higher resolution and more detailed data, it can help decision-makers formulate effective water resource management and environmental protection measures.