Impact of Terrain and Cloud Cover on the Distribution of Incoming Direct Solar Radiation over Pakistan

Sultan, Sadia; Wu, Renguang; Iftikhar, Ahmed

doi:10.4236/jgis.2014.61008

Cited by 4 publications

(5 citation statements)

References 18 publications

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“…The block diagram for global solar irradiation calculation over complex terrain is show in Figure 3 According to the model given by [43] " based on the theory of direct solar irradiation over inclined surface [44] , we have the following relation, Where; Where, H is the incoming global solar radiation over the flat surface; S is relative sunshine duration, which we have calculated based on corrected cloud fraction data, and a, b, c are empirical coefftcients. The detail can be found in [30] Global solar Figure 3 Simplified block diagram for the global solar radiation model…”

Section: Methodsmentioning

confidence: 99%

“…There; Hra p is the monthly topographic reflected solar radiation ( MJm -2 ) 5 H is the monthly incoming global solar radiation (MJm -2 ) as is monthly mean surface albedo is surrounding areas, and V is the sky view factor (openness model) Model for monthly global solar radiation and for sky view factor, that is openness model has already been discussed in previous papers [30] [48] [49].…”

Section: Hra J3 = Has(l-v)mentioning

confidence: 99%

“…The distributed modeling approach has been considered more useful and relatively accurate [27] [28] and can give better understanding of solar radiation distribution over the complex terrain [29] [30] . The development of modern spatial information technologies, especially geographic infonnation systems, remote sensing science and new terrain and satellite datasets provide better platform for distributed modeling [22] [31] .…”

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confidence: 99%

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Impact of slope, aspect and cloud cover on the distribution of incoming global solar radiation over Pakistan

Sultan

Lin

et al. 2015

2015 23rd International Conference on Geoinformatics

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We use a distributed modeling approach to investigate the spatial and quantitative distribution of incoming global solar radiation (GSR) falling over the complex terrain using remote sensing (R S) and geographical information system (GIS). To apply distributed model, we use SRTM digital elevation models (DEM) for impact assessment of slope, aspect orientation and correcting possible sunshine duration over the inclined surface. Similarly, to evaluate the impact of cloud cover on incoming global solar radiation amount and spatial distribution, we use MODIS Level-2 (L2) cloud fraction products and observational data of cloud cover from 21 meteorological observatories in Pakistan. As an input for incoming GSR model, the direct, diffused, and terrain reflected components ofGSR were employed. The model results show clear quantitative influences of local topography based on slope angles and cloud cover variations on the distribution ofGSR in the North and Northwest of Pakistan. Similarly, slope and aspect influences are evident over the mountainous areas in Himalaya, Karakorum and Hindukush Ranges in North and Suleiman Ranges in Northwest. Furthermore, terrain effect for eastern and western slopes is not significant; the slopes receive almost the same radiation due to the orientation of topography and latitudinal consistency, but inter-shielding effect in eastern-western oreintation is more prominent compared to the one in northern southern.

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Section: Methodsmentioning

confidence: 99%

Section: Hra J3 = Has(l-v)mentioning

confidence: 99%

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confidence: 99%

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Impact of slope, aspect and cloud cover on the distribution of incoming global solar radiation over Pakistan

Sultan

Lin

et al. 2015

2015 23rd International Conference on Geoinformatics

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“…the horizontal surface received solar radiation is all made up mainly of direct radiation, with DSR component reaching a minimum [7].…”

Section: Methodsmentioning

confidence: 99%

“…Pakistan is divided into three major geographic areas: the northern highlands, the Indus River plain, and the Baluchistan Plateau. The northern highlands of Pakistan contain the Karakoram, Hindu Kush and Pamir mountain ranges, which have some of the world's highest peaks, including K2 (8611 m/28,251 ft) and Nanga Parbat (8126 m/26,660 ft) [7]. The Baluchistan Plateau lies to the West, and the Thar Desert in the East.…”

Section: Study Areamentioning

confidence: 99%

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

Sultan¹,

Wu²,

Ahmad³

et al. 2014

JGIS

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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.

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Components of near-surface energy balance derived from satellite soundings – Part 1: Noontime net available energy

et al. 2015

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This paper introduces a relatively simple method for recovering global fields of monthly midday (13:30 LT) near-surface net available energy (the sum of the sensible and latent heat flux or the difference between the net radiation and surface heat accumulation) using satellite visible and infrared products derived from the AIRS (Atmo-spheric Infrared Sounder) and MODIS (MODerate Resolution Imaging Spectroradiometer) platforms. The method fo-cuses on first specifying net surface radiation by considering its various shortwave and longwave components. This was then used in a surface energy balance equation in conjunction with satellite day-night surface temperature difference to derive 12 h discrete time estimates of surface system heat capacity and heat accumulation, leading directly to retrieval for surface net available energy. Both net radiation and net available energy estimates were evaluated against ground truth data taken from 30 terrestrial tower sites affiliated with the FLUXNET network covering 7 different biome classes. This revealed a relatively good agreement between the satellite and tower data, with a pooled root-mean-square deviation of 98 and 72 W m −2 for monthly 13:30 LT net radiation and net available energy, respectively, although both quantities were underestimated by approximately 25 and 10 %, respectively , relative to the tower observation. Analysis of the individual shortwave and longwave components of the net radiation revealed the downwelling shortwave radiation to be main source of this systematic underestimation.

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Impact of Terrain and Cloud Cover on the Distribution of Incoming Direct Solar Radiation over Pakistan

Cited by 4 publications

References 18 publications

Impact of slope, aspect and cloud cover on the distribution of incoming global solar radiation over Pakistan

Impact of slope, aspect and cloud cover on the distribution of incoming global solar radiation over Pakistan

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

Components of near-surface energy balance derived from satellite soundings – Part 1: Noontime net available energy

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