فهرست نشریات علمی دسترسی آزاد ایران

This study presents a comparative analysis of solar radiation across selected South Asian regions using the Angstrom–Prescott linear regression model. This model estimates monthly average global solar radiation on horizontal surfaces from bright sunshine duration, considering latitude and longitude. The monthly average solar radiation data for 2025 were calculated and compared with model-based estimates across different zones, demonstrating strong agreement between observed and predicted values through graphical and statistical analyses. Among the eight locations we analyzed, Male received the highest annual solar radiation value 3890.61, whereas Kabul recorded the lowest 3146.65 .The seasonal variations indicated that Male experienced higher solar radiation and brighter sunshine duration from February to June and July to September, with values ranging from (36.12 to 40.23 ).In contrast, Kabul’s sunshine duration during the same periods was lower, ranging between (28.91 to 33.25 ) . Both locations showed a decline in sunshine duration between October and January, with Male ranging from (40.31 to 38.96 ) and Kabul from (32.91 to 30.68 ).Additionally, clearness index analysis confirmed that Male experienced the clearest atmospheric conditions with minimal cloud cover, whereas Kabul was more affected by cloudiness. These results provide valuable insights for future solar energy assessments in South Asia.