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Study of solar irradiance at low land Simara Nepal, using Angstrom\'s empirical model

Author Affiliations

  • 1Department of Physics, Patan Multiple Campus, T.U. Nepal
  • 2Institute of Engineering, Tribhuvan University, Nepal

Res.J.chem.sci., Volume 7, Issue (7), Pages 45-49, July,18 (2017)


The daily solar irradiance was measured using CMP6 first class Pyranometer of the low land region Simara (27.160 N, 84.980 E) Nepal. The solar radiation coming to earth surface primarily depends on the climate conditions. In developing countries like Nepal, there is no sufficient reliable data of solar irradiance and measuring instruments. In the absence of sufficient data there is a need of an empirical model to estimate the solar irradiance which seems very important in every region of Nepal. This empirical model use several meteorological parameters among them sunshine hour are mostly and commonly used parameters. The least square regression is performed to derive these constants. The measured and predicted solar irradiance were tested using mean percentage error (MPE), mean bias error (MBE) and root mean square (RMSE) Further, we calculated corresponding value of coefficient of determination (R2). The predicted and measured values get close to each other and hence they are remarkable. Finding regression constants are used to predict the GSR at that location for further utilization. This Solar energy can be utilized to mitigate energy crisis at that location. In addition, this finding also helps to grow more crops or foods on the basis of rainfall, sun shine hour, humidity, temperature.


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