Regional and Monthly Assessment of  Possible Sunshine Duration in Pakistan:  A Geographical Approach

Ambreen, Romana; Ahmad, Iftikhar; Qiu, Xinfa; Li, Menjei

doi:10.4236/jgis.2015.71006

Cited by 7 publications

(4 citation statements)

References 13 publications

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“…To simulate SD accurately, factors that affect the amount of SD that reaches the surface of the Earth, such as topography of the underlying surface, obstruction of SD from adjacent elevations and the solar angle at a given time, must be inculcated in the model simulation. By using a complex computational algorithm (see [44] for more details), our model was able to inculcate all these factors in SD simulation, thereby making it robust when compared to both IDW and kriging (see [49]). For the southern slope direction, January had the highest slope, followed by October, then April and finally July.…”

Section: Resultsmentioning

confidence: 99%

High Spatial Resolution Simulation of Sunshine Duration over the Complex Terrain of Ghana

Adamu

Qiu

Shi

et al. 2019

Sensors

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In this paper, we propose a remote sensing model based on a 1 × 1 km spatial resolution to estimate the spatio-temporal distribution of sunshine percentage (SSP) and sunshine duration (SD), taking into account terrain features and atmospheric factors. To account for the influence of topography and atmospheric conditions in the model, a digital elevation model (DEM) and cloud products from the moderate-resolution imaging spectroradiometer (MODIS) for 2010 were incorporated into the model and subsequently validated against in situ observation data. The annual and monthly average daily total SSP and SD have been estimated based on the proposed model. The error analysis results indicate that the proposed modelled SD is in good agreement with ground-based observations. The model performance is evaluated against two classical interpolation techniques (kriging and inverse distance weighting (IDW)) based on the mean absolute error (MAE), the mean relative error (MRE) and the root-mean-square error (RMSE). The results reveal that the SD obtained from the proposed model performs better than those obtained from the two classical interpolators. This results indicate that the proposed model can reliably reflect the contribution of terrain and cloud cover in SD estimation in Ghana, and the model performance is expected to perform well in similar environmental conditions.

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Section: Resultsmentioning

confidence: 99%

High Spatial Resolution Simulation of Sunshine Duration over the Complex Terrain of Ghana

Adamu

Qiu

Shi

et al. 2019

Sensors

Self Cite

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“…Based on the calculation model of SASR on the sloped surface, we can reconsider the corresponding Equations and build the distributed model (or subparagraph integral mathematical model) to calculate PSD and SASR under terrain relief on Mars. Based on the existing theoretical model of solar radiation on Mars [1,2,9,10,26,27,30,32,[37][38][39] and the Astronomical theory on Mars, combining with the theoretical model of solar radiation on Earth [6,8,11,12,14,15,17,63,64,91,[94][95][96][97][98][99][100][101], the SASR model which is suitable for Mars is proposed. It can be given by the following steps:…”

Section: The Law Of Revolution and Rotation Of Marsmentioning

confidence: 99%

“…Therefore, in each solar hour angle, SASR may be shielded by the terrain relief. The distributed model (or called subparagraph integral mathematical model) was generally adopted to calculate the actual SASR and PSD over the rugged terrain [6,8,11,12,14,15,17,64,96,97,109] in DEM. It was given in the following part.…”

Section: Calculation Model Of the Psd And Sasr On The Sloped Surfacementioning

confidence: 99%

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DEM Based Study on Shielded Astronomical Solar Radiation and Possible Sunshine Duration under Terrain Influences on Mars by Using Spectral Methods

Lin

Chen

2021

IJGI

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Solar radiation may be shielded by the terrain relief before reaching the Martian surface, especially over some rugged terrains. Yet, to date, no comprehensive studies on the spatial structure of shielded astronomical solar radiation (SASR) and the possible sunshine duration (PSD) on Mars have been conducted by previous researchers. Previous studies generally ignored the influences of the terrain on the SASR and PSD, which resulted in a corresponding unexplored field on SASR. The purpose of this paper is to study the Martian spatial-temporal structure of SASR and the PSD under terrain influences. In this paper, the theory of Earth’s SASR, the previous Martian SASR model and the theory of planetary science were combined to propose the SASR model that can be applied to Mars. Then, with the spectrum method theory of geography, we defined two new concepts of spectrums to explore the spatial-temporal distribution of SASR and PSD in different Martian landforms. We found SASR and PSD on Mars were significantly influenced by terrain relief and latitude and showed sufficient regularity, which can be concluded as a gradual attenuation with terrain relief and a regularity of latitude anisotropy. The latitude anisotropy feature is a manifestation of the terrain shielding effect. With the latitude varying, SASR and PSD at different temporal scale generally showed different features with those of Earth, which may be attributed to the imbalanced seasons caused by Martian moving orbits and velocity. Compared to PSD, SASR showed more regular variation under terrain relief and was more influenced by the terrain relief which revealed that SASR is more sensitive to terrain relief than PSD. Additionally, the critical area is a quantitative index to reflect the stable spatial structure of SASR and PSD in different landforms and may be viewed as the minimum test region of sample areas. The corresponding result of the experiments herein indicated that either spectrum can effectively depict the spatial-temporal distribution of SASR and PSD on Mars under terrain relief and deepen the understanding of the variation of SASR and PSD influences by terrain. The critical area of either spectrum can be employed to explore and determine the stable spatial structure of SASR and PSD in different landforms. The proposed Martian SASR model and the new spectral method theory shed new light on revealing the spatial-temporal structure of SASR and PSD under terrain influences on Mars.

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Deriving the slope-mean shielded astronomical solar radiation spectrum and slope-mean possible sunshine duration spectrum over the Loess Plateau

Chen

2020

J. Mt. Sci.

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Regional and Monthly Assessment of Possible Sunshine Duration in Pakistan: A Geographical Approach

Cited by 7 publications

References 13 publications

High Spatial Resolution Simulation of Sunshine Duration over the Complex Terrain of Ghana

High Spatial Resolution Simulation of Sunshine Duration over the Complex Terrain of Ghana

DEM Based Study on Shielded Astronomical Solar Radiation and Possible Sunshine Duration under Terrain Influences on Mars by Using Spectral Methods

Deriving the slope-mean shielded astronomical solar radiation spectrum and slope-mean possible sunshine duration spectrum over the Loess Plateau

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