## 4 Model Analysis and Results
In contrary, high values of such parameters that are responsible for very high attenuation and create fast changes in the consistency of the atmosphere, decrease the accuracy of the model. Furthermore, temperature affects the accuracy of the model in cases of very low values. \begin{table}
\begin{tabular}{l l} \hline Coefficient of Multiple Correlation \(R^{2}\) & 0.7612 \\ \hline Adjusted Coefficient of Multiple Correlation & 0.7610 \\ \hline Residual Mean Variance & \(5.1482\times 10^{-4}\) \\ \hline Sum of Regression Variance & 19.9718 \\ \hline Sum of Residual Variance & 6.2638 \\ \hline Sum of Total Variance & 26.2356 \\ \hline \end{tabular}
\end{table} 
Table 4: Validity Parameter Values for the Experimental Model of Equation (6). \begin{table}
\begin{tabular}{c c|c c} \hline \(b_{0}\) & \(9.4600\times 10^{-1}\) & \(b_{7}\) & \(-2.2800\times 10^{-2}\) \\ \hline \(b_{1}\) & \(4.6566\times 10^{-9}\) & \(b_{8}\) & \(9.7646\times 10^{-7}\) \\ \hline \(b_{2}\) & \(5.9130\times 10^{-12}\) & \(b_{9}\) & \(2.0000\times 10^{-3}\) \\ \hline \(b_{3}\) & \(-5.0450\times 10^{-5}\) & \(b_{10}\) & \(1.1043\times 10^{-6}\) \\ \hline \(b_{4}\) & \(-1.0050\times 10^{-7}\) & \(b_{11}\) & \(4.9150\times 10^{-5}\) \\ \hline \(b_{5}\) & \(-3.2280\times 10^{-4}\) & \(b_{12}\) & \(-9.4390\times 10^{-7}\) \\ \hline \(b_{6}\) & \(-2.2190\times 10^{-4}\) & \(b_{13}\) & \(-2.2860\times 10^{-8}\) \\ \hline \end{tabular}
\end{table} 
Table 3: Coefficient values of Equation (6). In order to more precisely investigate the behavior of the model in various weather conditions, the results of empirical model and experimental measurements are presented for specific days. In the blue box are the measurements between 00:00 a.m. to 05:00 a.m., while in the orange one are the measurements between 8:00 pm to 11:59 p.m. At the right side of the Figures 5-11, the wind speed and the rain rate are presented for the whole day. In Figures 5 and 6, the results of windy nights are presented. It could be observed that between 00:00 and 05:00 the wind was lower than 5 m/s, the model had a good fitting, while between 20:00 and 23:59, the wind was over 5 m/s with severe gusts, where the model diverged more, but was still close to the experimental measurements. Figure 3: Experimental results versus the corresponding from the experimental model of Equation (6). Figure 2: Experimental and regression model of Equation (6) results. In Figure 7, it can be observed that a lack of accuracy before precipitation took place due to unstable and fast changes in weather conditions. It was clear that the very high value of the relative humidity decreased the accuracy of the model, as the attenuation coefficient was very high. On the other hand, between 21:00 and 23:59, a few hours after precipitation and with very low wind speed where the weather conditions were mild and stable, the model presented a very high accuracy. In Figure 8, the results of the model are presented in cases of sudden and severe wind gusts and changes. Between 00:00 and 05:00, this phenomenon was more severe and at the same time, the relative humidity increased and the model lacked accuracy in some cases. However, as shown in Figure 6, between 20:00 and 23:59, the model showed very high accuracy in predicting the attenuation coefficient due to mild conditions. The partial coefficient of multiple correlation, \(R^{2}\), is presented in the following Table 5, for the days presented in Figures 5-8. Figure 4: Measurements of temperature (second from the top panel), wind speed (third from the top panel), and relative humidity (lower panel), for each sample of regression model and experimental data. Figure 5: Experimental measurements and model predictions, i.e., Equation (6), for 6 February 2020. Figure 6: Experimental measurements and model predictions, i.e., Equation (6), for 16 February 2020. Figure 8: Experimental measurements and model predictions, i.e., Equation (6), for 30 January 2020. Figure 7: Experimental measurements and model predictions, i.e., Equation (6), for 15 February 2020.