## 3 Experimental Measurement of Water Temperature Field  
### Experimental Testing System  
To establish the relationship between the background temperature field of the water body and the meteorological and hydrological environment, a testing platform for the background temperature field of the water body was developed. This platform employsa Conductivity-Temperature-Depth (CTD) profiler, a mid-wave cooled infrared thermal imager, and ultra-fine thermocouples to measure the vertical profile temperature, surface temperature, and skin layer temperature of the water body, respectively. A multi-parameter integrated meteorological and hydrological station is utilized to simultaneously monitor and record various meteorological and hydrological parameters. By analyzing the evolution of the water temperature field in conjunction with changes in meteorological and hydrological parameters, the influence patterns of these parameters on the water temperature field are elucidated, and the interrelationships between them are established. The composition and interrelationships of the experimental system are depicted in Figure 3.  
The customized YG-QXZ multi-parameter integrated meteorological and hydrological monitoring station comprises three main components: meteorological sensors, a meteorological data acquisition unit, and meteorological data acquisition software. It integrates functions for meteorological data collection, storage, transmission, and statistical analysis, enabling the measurement of a wide range of meteorological and hydrological parameters, including atmospheric temperature, humidity, pressure, wind speed, wind direction, solar shortwave radiation, atmospheric longwave radiation, and water body longwave radiation. Specifically, the atmospheric temperature sensor has a measurement range of \(-\)40 to 100 \({}^{\circ}\)C, a resolution of 0.1 \({}^{\circ}\)C, and an accuracy of \(\pm\)0.1 \({}^{\circ}\)C; the atmospheric humidity sensor has a measurement range of 0 to 100%RH, a resolution of 0.1%RH, and an accuracy of \(\pm\)3%RH; the wind speed sensor has a measurement range of 0 to 70 m/s, a resolution of 0.1 m/s, and an accuracy of \(\pm\)0.3 m/s; the shortwave radiometer has a measurement range of 0 to 2000 W/m\({}^{2}\), a spectral range of 300 to 3000 nm, a sensitivity of 7 to 14 \(\upmu\)V/Wm\({}^{-2}\), and an accuracy of \(\pm\)3%; the longwave radiometer has a measurement range of 0 to 2000 W/m\({}^{2}\) and a spectral range of 3.5 to 50 \(\upmu\)m. The IRMC-615 MW mid-wave cooled infrared thermal imager is employed to measure the surface temperature field of the water body. This thermal imager utilizes a stirling cooler to maintain a stable operating temperature, with infrared detector elements arranged in a rectangular array within the focal plane. Each pixel in the image corresponds to an independent detection unit that converts infrared radiation into an electrical signal. The thermal imager has a temperature measurement range of 5 \({}^{\circ}\)C to 150 \({}^{\circ}\)C, a thermal sensitivity of \(<\)20 mK, and a resolution of  
Figure 3: Structure and relation of water temperature field test system.  
[resolution value]. The RBRconcerto\({}^{\circ}\)C.T.D (RBR, Ottawa, ON, Canada) is a submersible Conductivity-Temperature-Depth (CTD) instrument equipped with temperature, pressure, and conductivity sensors, designed for measuring the temperature, depth, and salinity of the vertical profile of the water body. The CTD has a temperature measurement range of \(-5\)\({}^{\circ}\)C to \(35\)\({}^{\circ}\)C, a temperature accuracy of \(\pm 0.002\)\({}^{\circ}\)C, a resolution of \(<\)0.00005 \({}^{\circ}\)C, a depth measurement range of 0 to 200 m, a depth accuracy of \(\pm 0.05\%\)FS, and a resolution of \(<\)0.001%FS. The K-type ultra-fine thermocouple features a temperature measurement range of 0 to 200 \({}^{\circ}\)C, a weld point diameter of \(<\)0.3 mm, a wire diameter of 0.2 mm, and a resolution of 0.01 \({}^{\circ}\)C.