Study of the total change of total solar radiation in the city of Baghdad

Abstract

The study aims to try to find a model for estimating the values of solar radiation in the city of Baghdad by presenting and studying models that estimated the values of solar radiation in the world, and both according to the radiation data of the studied area, and accordingly, this study relied on the presentation of (14) models in calculating the solar radiation, The standard deviation (statistical test) for a set of models was applied and the optimal model was developed to estimate the total solar radiation in the city of Baghdad. The results showed that the optimal model in calculating the total solar radiation in the city of Baghdad is model (3), so the amount of solar radiation according to the optimal model is about (17.324) and its standard degree of the model is about (0.175) Through this model, the total solar radiation is calculated for the city of Baghdad and the total change of the monthly equations for the quantities of the total solar radiation to the city for the period between (1987-2019), the researchers concluded that the total change recorded an increase for all months of the year in the city of Baghdad which was proven by the general trend coefficient, which records a positive value. The total solar radiation was calculated between the three climatic cycles of the city of Baghdad by dividing the study period into three climatic cycles, The first climatic extending from (1987-1997), The second climatic extending from (1998-2008), The third climatic extending from (2009-2019) The total solar radiation amount according to the first climatic cycle was recorded (16.8) and the record of the second climatic cycle is about (17.6) of the amount total solar radiation, and recorded the amount (17.7) for the third climatic cycle. The rate of change between the first and second climatic cycles is also calculated, which amounted to about (0.8) while the rate of change for the same two previous climatic cycles was about (4.76), as for the rate of change between the two climatic, the second and third it reached (0.10), and the rate of change reached (0.560). the researcher also calculated the change in the difference between the three climatic cycles.