scholarly journals Estimation of evapotranspiration through an improved daily global solar radiation in SEBAL model: a case study of the middle Heihe River Basin

2020 ◽  
Author(s):  
Jingqiu Yin ◽  
Xinfa Qiu ◽  
Shoubo Li ◽  
Guoping Shi ◽  
Huiyu Liu
Keyword(s):  
Solar Radiation ◽  
River Basin ◽  
Global Solar Radiation ◽  
Heihe River Basin ◽  
Bias Error ◽  
Heihe River ◽  
Spatiotemporal Resolution ◽  
Surface Parameters ◽  
The Mean ◽  
Sebal Model

Abstract. The agricultural activities, hydrologic cycle, and ecological environment are seriously influenced by evapotranspiration (ET), especially in arid and semi-arid areas. A new method for estimating daily global solar radiation (GSR) over rugged terrains in the middle Heihe River Basin is developed on the basis of Iqbal model C. And with the land surface parameters retrieved from multisource remote sensing data, a daily surface ET on June 21–24, 2009, is simulated by using surface energy balance algorithm for land (SEBAL) model. The results show: 1. An improved daily GSR with a resolution of 100 m × 100 m is implemented. The mean absolute bias error (MABE) is 9 W/m2, and the mean absolute relative bias error (MARBE) is 2.5 %. The MABE of the daily GSR using the SEBAL model is 122.2 W/m2, and the MARBE is 33.9 %. 2. The spatial distribution of the daily GSR is more reasonable using the improved model than the original model. The GSR is larger on a sunny slope (an open place) than on a shady slope (a rugged place). 3. Bringing the new model into SEBAL significantly improves the accuracy of the ET. The MABE of ET decreases from 2.1 mm (original scheme) to 0.6 mm (improved scheme), and the MARBE declines from 44 % to 13 % accordingly. Moreover, the spatiotemporal resolution of the ET simulation is effectively improved by the combined moderate-resolution imaging spectroradiometer and thematic mapper surface parameters. 4. All highest ET value appeared in all types of water bodies, followed by farmland, forest, wetland, and residential areas, the lowest values appeared over bare rock land. The water consumption in these areas is dominated by agriculture. The new results provide better theoretical basis and scientific guidance for ecosystem protection and sustainable utilization of water resources.

scholarly journals Calibration of Ångström-Prescott Coefficients to Estimate Global Solar Radiation in Côte d’Ivoire

2021 ◽  
Vol 17 (37) ◽  
pp. 24
Author(s):  
Maurice Aka Djoman ◽  
Wanignon Ferdinand Fassinou ◽  
Augustin Memeledje
Keyword(s):  
Solar Radiation ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Global Solar Radiation ◽  
Mean Bias Error ◽  
Bias Error ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
The Mean ◽  
Weather Stations

In this study, we used monthly mean daily global radiation data and sunshine durations from nine (9) weather stations in Côte d’Ivoire to determine the annual Ångström-Prescott coefficients. The calibration of the Ångström-Prescott equation has been done through linear regression using the least square method. The empirical coefficients obtained are utilized to predict the global horizontal irradiance over the nine (9) weather stations of interest. Estimated and measured global radiations were compared using the root mean square error (RMSE), the mean bias error (MBE), the mean absolute bias error (MABE), the mean percentage error (MPE), the Nash-Sutcliffe coefficient of efficiency (NSE), and the statistic -test (). The low values of the statistic t-test (from 0.10 to 1.07) and MPE (from -0.413 to 0.201) indicate a good performance of the model. The high values of the coefficient of determination R² (from 0.9776 to 0.9916) show a remarkable agreement between predicted and measured global solar radiations. This remark is also confirmed by the high values of NSE (from 0.8671 to 0.9819) closer to 1. The obtained values of MBE (from -18.17 to 8.69 kWh/m²), MABE (from 7.16 to 8.52 kWh/m²), and RMSE (69.1 to 167.3 kWh/m²) show a low deviation or bias between the estimate and the measurements. The Ångström-Prescott coefficients determinants are consistent and can be used to efficiently calculate the global horizontal irradiance. The model established can be recommended to be used in the nine (9) weather stations to accurately estimate global solar radiation on horizontal surfaces.

scholarly journals A New Algorithm of the FPAR Product in the Heihe River Basin Considering the Contributions of Direct and Diffuse Solar Radiation Separately

2015 ◽  
Vol 7 (5) ◽  
pp. 6414-6432 ◽  
Author(s):  
Li Li ◽  
Yongming Du ◽  
Yong Tang ◽  
Xiaozhou Xin ◽  
Hailong Zhang ◽  
...  
Keyword(s):  
Solar Radiation ◽  
River Basin ◽  
Heihe River Basin ◽  
Heihe River ◽  
Diffuse Solar Radiation ◽  
The Heihe River Basin

scholarly journals Forecasting of Solar Radiation using an Empirical Model

2019 ◽  
Vol 01 (02) ◽  
pp. 212-219 ◽  
Author(s):  
Djelloul BENATIALLAH ◽  
Kada BOUCHOUICHA ◽  
Ali BENATIALLAH ◽  
Abdelkader HARROUZ ◽  
Bahous Nasri ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Climatic Conditions ◽  
Mean Bias Error ◽  
Percentage Error ◽  
Bias Error ◽  
Energy Needs ◽  
Natural Energy ◽  
The Mean

Global demand for energy is increasing rapidly and natural energy resources such as oil, gas and uranium are declining due to the widespread diffusion and development of the industry in recent years. To cover energy needs, research is being conducted on renewable energy. One of the renewable energies that can meet the world's demand so far is solar energy, which is free and inexhaustible in most parts of the world, and it has become an economic source. In this article we will make a forecast of the empirical Campbell model which will allow us to estimate the daily global irradiation on a horizontal plane and to compare it with the results measured at the Adrar site. The results show that the mean absolute percentage error (MAPE) less than 7%, the mean bias error does not exceed 3% in absolute value, relative RMSE does not exceed 7% and the correlation coefficient greater than 0.99 for the annual global radiation. It was concluded that this model could be used to predict the global solar radiation for Adrar site and for other sites with similar climatic conditions.

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