# An Experimental Study on the Reflection Characteristics of Laser Echo Light Waves
## 4 Analysis and Discussion
### Atmospheric Refractive Index Structure Constant  
This paper uses the scintillation index method to measure the atmospheric refractive index structure constant \(C_{n}^{2}\) to evaluate the turbulence conditions in different weather conditions in the current area. This method first needs to record the mean light intensity \(\langle I\rangle\) received by the optical power meter and the calculated standard deviation s, and then substitute them into (3) to obtain the logarithmic amplitude variance \(\sigma_{x}^{2}\). Then, the logarithmic amplitude variance \(\sigma_{x}^{2}\), the communication transmission distance L, the receiving port diameter, and the transmitting port diameter are used to obtain the precise value of the atmospheric refractive index structure constant \(C_{n}^{2}\). The receiving port diameter of 105 mm, and the transmitting port diameter of 5 mm. To obtain the law of refractive index variation in the atmospheric turbulent structure under different weather conditions, 22 groups of experimental data (T1-T22) were selected from the collected data for processing to obtain the mean value of light intensity and its standard deviation. The results are shown in Tables 3 and 4. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Measuring** & & & & & & \\
**Samples** & & & & & & \\ \hline T13 & 12 May 2024 & Sunny & 16–30 & 0.3–1.0 & 63 & 38.7\% & 0.519 \\ T14 & 25 June 2024 & Sunny & 24–38 & 0.3–0.6 & 84 & 26.4\% & 0.545 \\ T15 & 18 May 2024 & Lightly rainy & 20–38 & 0.5–1.5 & 71 & 65.7\% & 0.425 \\ T16 & 16 June 2024 & Lightly rainy & 21–28 & 0.8–1.2 & 40 & 62.4\% & 0.454 \\ T17 & 25 May 2024 & Moderately rainy & 20–38 & 1.0–1.2 & 51 & 74\% & 0.388 \\ T18 & 15 July 2024 & Moderately rainy & 24–34 & 0.6–1.0 & 46 & 71.7\% & 0.402 \\ T19 & 3 July 2024 & Heavily rainy & 22–27 & 0.8–1.5 & 34 & 82.1\% & 0.215 \\ T20 & 5 July 2024 & Heavily rainy & 21–28 & 1.0–1.5 & 36 & 86.6\% & 0.206 \\ T21 & 20 May 2024 & Cloudy & 19–33 & 3.4–4.5 & 46 & 39\% & 0.195 \\ T22 & 18 June 2024 & Cloudy & 24–35 & 0.3–0.8 & 48 & 34.7\% & 0.270 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Experimental weather conditions and scintillation indexes of Link 2 samples T13–T22. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Measuring** & & & & & \\
**Samples** & & & & & \\ \hline T1 & Sunny & 3.03 \(\times\)\(10^{-17}\) & 9.35 \(\times\)\(10^{-17}\) & 9.34 \(\times\)\(10^{-19}\) & 1.50 \(\times\)\(10^{-17}\) \\ T2 & Sunny & 4.01 \(\times\)\(10^{-17}\) & 1.30 \(\times\)\(10^{-16}\) & 1.64 \(\times\)\(10^{-18}\) & 1.69 \(\times\)\(10^{-17}\) \\ T3 & Snowy & 9.17 \(\times\)\(10^{-18}\) & 8.31 \(\times\)\(10^{-17}\) & 9.08 \(\times\)\(10^{-19}\) & 7.85 \(\times\)\(10^{-18}\) \\ T4 & Snowy & 1.59 \(\times\)\(10^{-17}\) & 6.96 \(\times\)\(10^{-17}\) & 3.00 \(\times\)\(10^{-18}\) & 1.09 \(\times\)\(10^{-17}\) \\ T5 & Lightly rainy & 7.63 \(\times\)\(10^{-18}\) & 2.05 \(\times\)\(10^{-17}\) & 2.22 \(\times\)\(10^{-18}\) & 3.57 \(\times\)\(10^{-18}\) \\ T6 & Lightly rainy & 9.76 \(\times\)\(10^{-18}\) & 2.23 \(\times\)\(10^{-17}\) & 4.03 \(\times\)\(10^{-18}\) & 3.45 \(\times\)\(10^{-18}\) \\ T7 & Moderately & 5.62 \(\times\)\(10^{-18}\) & 1.23 \(\times\)\(10^{-17}\) & 3.61 \(\times\)\(10^{-19}\) & 1.84 \(\times\)\(10^{-18}\) \\ T8 & Moderately & & & & \\ \hline T9 & Heavily rainy & 3.25 \(\times\)\(10^{-18}\) & 1.18 \(\times\)\(10^{-17}\) & 1.39 \(\times\)\(10^{-18}\) & 1.22 \(\times\)\(10^{-18}\) \\ T10 & Heavily rainy & 3.78 \(\times\)\(10^{-18}\) & 1.03 \(\times\)\(10^{-17}\) & 1.83 \(\times\)\(10^{-18}\) & 1.21 \(\times\)\(10^{-18}\) \\ T11 & Cloudy & 2.42 \(\times\)\(10^{-18}\) & 5.78 \(\times\)\(10^{-18}\) & 1.45 \(\times\)\(10^{-18}\) & 5.72 \(\times\)\(10^{-19}\) \\ T12 & Cloudy & 2.75 \(\times\)\(10^{-18}\) & 8.03 \(\times\)\(10^{-18}\) & 6.11 \(\times\)\(10^{-19}\) & 1.28 \(\times\)\(10^{-18}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Atmospheric refractive index structure constants of Link 1 sample T1–T12. intensity is.