# Forecasting the Distortion in Solar Radiation during Midday
## 3 Results and Discussion
### Testing the Performance of the Proposed Technique in the Second Location (Al-Kharj City)  
To investigate the performance of the proposed technique in forecasting the distortion in solar radiation during midday hours in different locations, another location was considered (Al-Kharj city). Three months from the beginning of the year (January, February, and May), two months from the middle of the year (July and August), and two months from the end of the year (November and December) are shown in this section. The tests of the solar radiation of the remaining months are included in Appendix B. Figure 9 shows the solar radiation and the DIs for days 4 to 9 of January. As it can be seen in this figure, the distortion in the solar radiation of day 4 is low, and the \(DI\) (the right figure) is 44. The \(DI\) value (44) is between 41 and 60, which clearly shows the effectiveness of the proposed technique in anticipating the low distortion of radiation distortion in the midday hours. The same conclusion is achieved from day 5 of January, in which the distortion is also less than 60 and the solar radiation is approximately clean. On the other hand, the \(DI\) of day 6 is 94.5 (in the high-distortion range), and the solar radiation in the midday hours is much distorted. It is also clear that the proposed technique succeeded in anticipating the presence of distortion in the midday hours. Moreover, the DIs of the other days (7, 8, 9) are higher than 60, which also implies higher distortion in the radiation, and the proposed technique succeeded in forecasting the presence of the distortion in the solar radiation of these days during the midday hours. Figure 8: The solar radiation of days 13–17 of August (**left**) and the distortion index (\(DI\)) (**right**). Figure 7: The solar radiation of days 1–5 of August (**left**) and the distortion index (\(DI\)) (**right**). Figure 10 shows the results of other days. The proposed technique succeeded in forecasting the higher distortion in days 27, 28, 29, and 30; as it can be seen, the DIs of these days are 68, 67, 108, and 50, respectively. Figure 11 presents some results of February. The proposed technique succeeded in forecasting the high distortion in day 5; as it can be seen, the _DI_ is 66 (higher than 60). On the other hand, the DIs of days 6, 7, and 8 are lower than 40, which indicated the lower distortion in the midday hours of these days. It failed on the first day, but this failure is tolerated since 46 is near to 40. In Figure 12, the _DI_ of day 25 (in February) is 53 (between 41 and 60), which means that the distortion is medium. The forecasting of the distortion level coincides with the actual distortion. In addition, the technique performed better in determining the distortion level in days 26 and 27 of February since the _DI_ is higher than 60. However, the _DI_ of day 28 is not coinciding with the actual distortion. The DIs of days 29 and 30 are less than 40, which means that the distortion level is low. Again, the proposed technique succeeded in forecasting the distortion level during midday hours on these two days. In Figure 13, the DIs of all the days (4, 5, 6, 7, 8, and 9 of March) are less than 40, which means that the distortion is low. The _DI_ level obtained from the proposed technique matches the actual distortion on these days. Figure 10: The solar radiation of days 25–30 of January (**left**) and the distortion index (_DI_) (**right**). Figure 9: The solar radiation of days 4–9 of January (**left**) and the distortion index (_DI_) (**right**). Figure 11: The solar radiation of days 4–9 of February (**left**) and the distortion index (_DI_) (**right**). Figure 12: The solar radiation of days 25–30 of February (**left**) and the distortion index (_DI_) (**right**). Figure 13: The solar radiation of days 4–9 of March (**left**) and the distortion index (_DI_) (**right**). As Figure 14 shows, the DIs of days 21, 23, and 26 are higher than 60, which means that the distortion is high during midday hours.