# 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)
However, the proposed technique failed in forecasting the distortion on day 22. Figure 15 shows some results for July. The _DI_ of the first day (#4) is 2 and it is zero on the third day (#6), which indicates the low distortion of solar radiation during midday hours. The proposed technique succeeded in this forecasting. Moreover, the DIs are higher than 60 on days 5 and 7 (the _DI_ of day 5 is 108.5 and it is 92.5 for day 7). This indicates the distortion is high during midday hours. However, the DIs of days 8 and 9 were 17.5 and 19, respectively (lower than 40), in which the radiation is clear in the early hours and has a little distortion during late hours. In Figure 16,the distortion in the solar radiation during middays hours is low. The proposed technique succeeded in forecasting the distortion levels as it calculated that the DIs of the all 5 days were less than 40 (which means the distortion is low). As shown in Figure 17, the proposed technique succeeded in forecasting the distortion level in most of the presented days (4 to 9 of August). The DIs of these days are less than 40, which means the distortion is low. The _DI_ of day 9 is 69.5, which means that the distortion is medium on this day, and the actual distortion is low. Figure 14: The solar radiation of days 21–26 of March (**left**) and the distortion index (_DI_) (**right**). Figure 15: The solar radiation of days 4–9 of July (**left**) and the distortion index (_DI_) (**right**). Figure 18 shows that the proposed technique succeeded in forecasting the distortion levels during midday hours on all of the days from 25 to 30 of August. Figure 19 shows that the DIs of days 4, 5, and 6 are 7, 6, and 6, respectively, for November which indicates the success of the proposed technique in predicting the distortion level (the distortion is low). As is shown, distortion in the solar radiation of days 8 and 9 is low and the calculated DIs are between 40 and 60, which means that the distortion is medium. Figure 16: The solar radiation of days 25–30 of July (**left**) and the distortion index (_DI_) (**right**). Figure 7:0 The solar radiation of days 4–9 of August (**left**) and the distortion index (_DI_) (**right**). Figure 7:1 The solar radiation of days 26–31 of August (**left**) and the distortion index (_DI_) (**right**). Figure 20 shows that the DIs of days 23 and 24 are higher than 60 which indicate that the proposed technique succeeded in determining the distortion levels during the midday hours of these 2 days. The \(DI\) of day 25 is 57.5, which is near 60 and indicates that the distortion is medium but near to a high distortion level. However, the \(DI\) of the last day is 43.5, which indicates that the distortion is medium. The \(DI\) of day 21 is 83 in which the proposed technique failed in forecasting the distortion level. Figure 21 shows the solar radiation and the \(DI\) levels of days 1 to 6 of December. As it reveals, the DIs of days 1 to 4 are less than 40, which means that the distortion level is low during the midday hours. The proposed technique succeeded in forecasting the distortion levels in these four days. The \(DI\) of the last day is about 60, which indicates that the distortion level is almost high, and the actual distortion in the solar radiation is high. However, the \(DI\) of day 5 is 84.5, in which the proposed technique failed in forecasting the distortion level of this day. Figure 22 shows the solar radiation and the associated \(DI\) levels of the days 16 to 21 of December. As seen in this figure, the proposed technique succeeded in forecasting the distortion levels during the midday hours of all of these days. Some other results obtained for this location (Al-Kharj city) for some days in the remaining months are listed in Appendix B (Figures A13-A22). Figure 7:2 The solar radiation of days 4–9 of November (**left**) and the distortion index (\(DI\)) (**right**).