GEOGRAPHY & CARTOGRAPHY CALCULATOR
Solar Radiation Terrain
A precise tool.
What is the Solar Radiation Terrain & How does it work?
Solar radiation reaching the Earth’s surface is modulated by the atmosphere, the Sun’s position in the sky, and the orientation of the receiving surface. The extraterrestrial solar irradiance (Iβ β 1367β―Wβ―mβ»Β²) is reduced by atmospheric transmissivity (Ο) and by the cosine of the solar incidence angle on the surface. When a terrain is inclined, the incidence angle depends not only on the solar altitude (ΞΈ) but also on the slope angle (Ξ²) and the aspect (Ξ³) relative to the solar azimuth (Ξ±). This relationship is captured by the cosineβofβincidence term, which can increase or decrease the received energy compared with a horizontal plane. By combining the geometric factor with surface properties such as albedo, we obtain the net solar radiation absorbed by the terrain. This quantity is essential for applications ranging from solarβenergy site assessment to hydrological modelling.
Q = I_{0}\,\tau\,\left[\cos\theta\cos\beta + \sin\theta\sin\beta\cos(\gamma-\alpha)\right]
Q = solar radiation on the slope (Wβ―mβ»Β²)
I_{0} = extraterrestrial solar irradiance (Wβ―mβ»Β²)
\tau = atmospheric transmissivity
\theta = solar altitude angle (Β°)
\beta = slope angle (Β°)
\gamma = aspect (Β° from north)
\alpha = solar azimuth (Β°)
I_{0} = extraterrestrial solar irradiance (Wβ―mβ»Β²)
\tau = atmospheric transmissivity
\theta = solar altitude angle (Β°)
\beta = slope angle (Β°)
\gamma = aspect (Β° from north)
\alpha = solar azimuth (Β°)
Parameters
Result
β
Frequently Asked Questions
What is extraterrestrial solar irradiance?
Extraterrestrial solar irradiance is the amount of solar energy received at the top of Earth’s atmosphere, approximately 1367 W/mΒ².
How does atmospheric transmissivity affect solar radiation?
Atmospheric transmissivity reduces solar radiation by allowing only a portion of the sunlight to pass through the atmosphere based on factors like weather conditions and altitude.
What is the role of solar incidence angle in this calculation?
The solar incidence angle determines how directly sunlight hits a surface. A steeper angle results in less energy reaching the surface due to cosine law effects.
How does terrain inclination impact solar radiation?
Terrain inclination affects the solar incidence angle by changing how sunlight strikes the surface, impacting the amount of energy received based on slope and aspect.
What is meant by solar altitude in this context?
Solar altitude refers to the angle between the Sun’s rays and the horizon. It influences the intensity of solar radiation reaching the Earth.
How does aspect relate to solar radiation on terrain?
Aspect is the compass direction a slope faces, which affects how much sunlight it receives throughout the day based on the Sun’s position.
Why is this calculator useful for geography and cartography?
This calculator helps in understanding solar energy distribution across different terrains, aiding in applications like agriculture, urban planning, and renewable energy projects.
Results are for informational purposes only and do not constitute professional advice.