Estimation and Investigation of Photosynthetically Active Radiation over Benin, Nigeria
Abstract
Photosynthetically active radiation (PAR) is an important input parameter for estimating plant productivity due to its key role in the growth and development of plants. In this study, the measured monthly average daily global solar radiation, relative humidity, wind speed, minimum and maximum temperature dataset was utilized to estimate and investigate the Photosynthetically active radiation (PAR) for Benin (latitude 6.32N, longitude 5.10
E and 77.8 m) located in the coastal region of Nigeria. The meteorological parameters used in this study were obtained from the archives of National Aeronautics and space Administration (NASA) for a period of thirty-eight years (1984-2021). The newly developed temperature PAR based models were tested using statistical indicators of the coefficient of determination (R2), Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), t – test and index of Agreement (IA) to ascertain the suitability and applicability of the models. The results show that photosynthetically active radiation (PAR) is higher during the dry season and is low during the rainy season. Based on the regression models developed, the linear model equation that contains the mean temperature and temperature ratio was observed to be the best for PAR estimation in Benin with R2, MBE, RMSE, MPE, t-test and IA value of 71.9
, -0.0283 MJ
, 0.4842 MJ
0.0670
0.1941 and 88.3428
respectively