Modeling of Diffuse Solar Radiation and Impact of Complex Terrain over Pakistan Using RS/GIS


Diffuse solar radiation is subject to the combined influence of ground and sky factors, such as topography, geography of the area and cloud cover. This study attempts to quantify the impacts of topography, sky factors and the cloud cover on the distribution of diffuse solar radiation over Pakistan. Distributed modeling approach by considering anisotropy scattering mechanism was adopted. Digital elevation model and observed data are used to derive average monthly diffuse solar radiation values over the rugged terrains of Pakistan. Extraterrestrial solar radiation model, sky view factor model (openness model) and digital elevation model (DEM) are applied to investigate the impacts of ground factors, while diffuse solar radiation model for horizontal surface was considered for sky factors. Furthermore, corrected MODIS cloud fraction data are incorporated using GIS plat form. Results show that the highest amount of diffused solar radiation occurs during the monsoon months along the eastern side of the River Indus, when the sky is covered by clouds of various heights and densities. The variation due to topography is evident in mountainous areas, particularly in the North Pakistan and over the Baluchistan Plateau.

Share and Cite:

Sultan, S. , Wu, R. , Ahmad, I. and Ahmad, M. (2014) Modeling of Diffuse Solar Radiation and Impact of Complex Terrain over Pakistan Using RS/GIS. Journal of Geographic Information System, 6, 404-413. doi: 10.4236/jgis.2014.64035.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Blood, P. (1994) Pakistan: A Country Study. Federal Research Division of the Library of Congress.
[2] Barbour, M., Burk, J. and Pitts, W. (1978) Terrestrial Plant Ecology. 2 Edition, Menlo Park, Cummings.
[3] Zekai, S. (2008) Solar Energy Fundamentals and Modeling Techniques. Springer, London.
[4] Dubayaha, R. and Richb, P.M. (1995) Topographic Solar Radiation Models for GIS. International Journal of Geographical Information Science, 9, 405-419.
[5] Dozier, J. (1980) A Clear-Sky Spectral Solar Radiation Model for Snow-Covered Mountainous Terrain. Water Resources Research, 16, 709-718.
[6] Bocqust, G. (1984) Method of Study and Cartography of the Potential Sunny Periods in Mountainous Areas. Journal of Climatology, 1, 587-596.
[7] Sultan, S., Renguang, W. and Ahmad, I. (2014) Impact of Terrain and Cloud Cover on the Distribution of Incoming Direct Solar Radiation over Pakistan. Journal of Geographic Information System, 6, 70-77.
[8] Amir, N.K. (2010) Climate Change Adaptation and Disaster Risk Reduction in Pakistan. In: Rajib Shaw, J.M.P.J.J.P., Ed., Climate Change Adaptation and Disaster Risk Reduction: An Asian Perspective, Vol. 5, Emerald Group Publishing Limited, 197-215.
[9] Sultan, S. and Ahmad, I. (2008) Determination of Daily Regional Scale Actual Evapotranspiration for Indus Sub-Basin Using Landsat ETM +. Pakistan Journal of Meteorology, 4, 49-58.
[10] Hay, J. (1979) Calculation of Monthly Mean Solar Radiation for Horizontal and Inclined Surfaces. Solar Energy, 23, 301-307.
[11] Gueymard, C. (1987) An Anisotropic Solar Irradiance Model for Tilted Surfaces and Its Comparison with Selected Engineering Algorithms. Solar Energy, 38, 367-386.
[12] Skartveit, A. and Olseth, J. (1985) Modelling Slope Irradiance at High Latitudes. Solar Energy, 36, 333-344.
[13] Perez, R., Stewart, R., Arbogast, C., Seals, R. and Scott, J. (1986) An Anisotropic Hourly Diffuse Radiation Model for Sloping Surfaces: Description, Performance Validation, Site Dependency Evaluation. Solar Energy, 36, 481-497.
[14] Bartoli, B., Cuomo, V., Amato, U., Barone, G. and Mattarelli, P. (1982) Diffuse and Beam Components of Daily Global Radiation in Genova and Macerata. Solar Energy, 28, 307-311.
[15] Liu, B. and Jordan, R. (1960) The Interrelationship and Characteristic Distribution of Direct, Diffuse and Total Solar Radiation. Solar Energy, 4, 1-19.
[16] Shahzad, S. (2011) Distribution of Global Solar Radiation over the Rugged Terrain of Pakistan. M.S. Thesis, Nanjing University of Information Science and Technology (NUIST), Nanjing.
[17] Wong, L.T. and Chow, W. (2001) Solar Radiation Model. Applied Energy, 69, 191-224.
[18] Weng, D. (1997) Studies on Radiation Climate of China. China Meteorological Press, Beijing. (In Chinese)
[19] Wang, L. and Qiu, X. (2009) Distributed Modeling of Direct Solar Radiation of Rugged Terrain Based on GIS. The 1st International Conference on Information Science and Engineering (ICISE), Nanjing, 26-28 December 2009, 2042-2045.
[20] Fu, B.P. (1983) Mountain Climate. Meteorology Press, Beijing. (In Chinese)
[21] Zhang, Y.S. (2000) Information Systems of Remotely Sensing Imagery. Science Press, Beijing. (In Chinese)
[22] Qamar-uz-Zaman, C., Arif, M., Ghulam, R. and Muhammad, A. (2009) Climate Change Indicators of Pakistan. Pakistan Meteorological Department, Islamabad.
[23] Rashed, M. and Shuanglin, L. (2012) Response of Summer Rainfall in Pakistan to Dust Aerosols in an Atmospheric General Circulation Model. Quarterly Journal of Hungarian Meteorological Science, 116, 323-333.
[24] Wang, S.Y., Robert, D., Gillies, R. and Jin, J.M. (2011) Changing Monsoon Extremes and Dynamics: Example in Pakistan. 36th NOAA Annual Climate Diagnostics and Prediction Workshop, Fort Worth, TX, 3-6 October 2011, 61-68.

Copyright © 2021 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.