## 5 Conclusions  
The Arabian Peninsula has rich potential for solar energy. Solar photovoltaic (PV) panels could be very important when it comes to harnessing solar energy over the AP. The AP, however, hosts some of the largest deserts in the world, which makes it frequently affected by dust storms that load large amounts of aerosols and dust into the atmosphere. Additionally, the AP hosts the Gulf Council Cooperation (GCC) countries, which are one of the largest oil and natural gas producers in the world. This large petrochemical industry also loads large amounts of anthropogenic aerosols into the atmosphere of the AP. This study focused on the assessment of the aerosol effects on solar irradiance in the AP. It also provided a machine learning tool to predict solar energy over the AP. Data from a moderate resolution imaging spectroradiometer (MODIS) instrument onboard the Terra satellite along with a radiative transfer model and the ResNet machine learning technique were integrated to predict direct solar irradiance on a horizontal surface over the Arabian  
Figure 14: Comparison of original (blue) and predicted (orange) at (**a**) 47.5\({}^{\circ}\) E, 20.5\({}^{\circ}\) N; (**b**) 50.5\({}^{\circ}\) E, 22.5\({}^{\circ}\) N.  
Peninsula. Solar irradiance data from 2015 to 2017 (100%) and from 2018 (70%) were then used as input to train the ResNet machine learning model in order to predict 2018 (remaining 30%) solar irradiance data. The prediction model achieved high-test scores, indicated by an MAE of \(\sim\)0.02, MSE of \(\sim\)0.005, and R\({}^{2}\) of 0.99 or higher. The aerosol loading in the atmosphere was found to affect solar irradiance in the eastern region of the AP, especially near the coastlines of the Arabian Gulf and the Sea of Oman (\(\sim\)15%) and central AP (\(\sim\)20%). Low solar irradiance was observed during March 2016 and 2017 in the eastern regions of the AP, which could be attributed to the high frequency of dust events during this time of the year. Compared to other locations in the AP, high solar irradiance was recorded in the southeast regions during winter and spring. The effect of major dust outbreaks blown over the AP during March 2009 and March 2012 was also examined. The results indicated a correlation between high aerosol loading and a decrease in solar irradiance. Data collection, data analysis, machine learning S.A.; Data collection, data analysis, writing, review and editing, A.F. ; Conceptualization, methodology, data analysis, writing--original draft preparation, M.A. ; review and editing, M.A. ; review and editing, H.D.K. All authors have read and agreed to the published version of the manuscript. Authors would like to acknowledge the support provided by the Deanship of Scientific Research (DSR) at the King Fahd University of Petroleum and Minerals (KFUPM) for funding this work through project No. DF181010. Not applicable. The AOD data were retrieved from the publicly available Giovanni website ([[https://giovanni.gsfc.nasa.gov/giovanni/](https://giovanni.gsfc.nasa.gov/giovanni/)]([https://giovanni.gsfc.nasa.gov/giovanni/](https://giovanni.gsfc.nasa.gov/giovanni/)), accessed on 1 July 2021). The authors are thankful to the Giovanni-platform staff as well the MODIS scientists and associated NASA personnel for the production of the AOD data used in this study. Author [PERSON] acknowledges the support of the Center of Research Excellence in Renewable Energy (COERE), KFUPM. The authors declare no conflict of interest. References  
[PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] A Review on Global Solar Energy Policy. _Renew. Sustain. Energy Rev._**2011**, _15_, 2149-2163. [CrossRef]  
Hyperwall: Monthly Solar Insolation. Available online: [[https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=30367](https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=30367)]([https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=30367](https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=30367)) (accessed on 27 October 2021). [PERSON].