Atmospheric radiation scattering/absorption

In summary, the conversation discusses the ability of the sun to heat a house through glass and the difficulty in accurately measuring solar radiation for vertical surfaces. The issue is that most measurements are based on a combination of direct and diffuse radiation, but for a North facing surface, the measured value would only be from diffuse radiation, mainly in the visible light portion of the spectrum. The conversation also considers the percentage of visible light and near IR in solar energy and questions whether only 50% of the insolation value can be used to calculate heat benefit. The speaker is seeking clarification on their understanding of these concepts.
  • #1
lurksalot
12
0
I am still trying to assess the ability of the sun to heat a house through glass and I am a bit stuck .
Most solar flux /radiation measurements I have found are based on a total of direct and diffuse radiation on a horizontal surface and then formulated for vertical surfaces with some cosine functions depending on orientation.
Now, at for example , a latitude of 53deg between October through to May (inclusive, being the UK heating season ) the total values are around 180Kwhrs/sqmtr for North and 490 Kwhrs/sqmtr South .
My issue is that the measured North figure will be purely be diffuse radiation and thus basically the energy would be from the visible portion of the spectrum ie light . On the basis that 97% of the solar power is in the visible and near IR range and that radiation diffused through H2O will have been absorbed and radiated at a higher wavelength , that the resultant 180Kwhrs on a North facing vertical face would be the energy of the visible light ?
Also on the basis that the energy from the sun is approx 45% visible light and 50% near IR would it be reasonable to assess that even on full disc sunshine only 50% of the insolation value could be used to calculate heat benefit ?
This probably sounds a bit daft but any clarification of my limited understanding of this would be of great benefit
Many thanks Kev
 
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  • #2
Any Help is appreciatted
 
  • #3


I can provide some insight into your question about atmospheric radiation scattering and absorption and its impact on solar energy for heating a house.

Firstly, it is important to understand that solar radiation is not purely composed of visible light, but also includes infrared and ultraviolet radiation. The amount of each type of radiation that reaches the Earth's surface is affected by various factors, including atmospheric conditions, cloud cover, and the Earth's tilt and rotation.

When solar radiation passes through the Earth's atmosphere, it is scattered and absorbed by particles and gases in the air. This scattering and absorption can change the direction and intensity of the radiation reaching the Earth's surface. In the case of your question, the diffuse radiation on a horizontal surface will be a combination of direct and scattered radiation, while the measured North figure would be mostly diffuse radiation.

In terms of the energy that can be used for heating, it is important to note that all types of solar radiation can contribute to heating. While visible light may be the most noticeable component, infrared radiation also carries significant heat energy. In fact, much of the heat from the sun is carried by infrared radiation. Therefore, the 180Kwhrs on a North facing vertical face would not just be from visible light, but also from infrared radiation.

Furthermore, the percentage of visible light and near infrared in the sun's total energy output may vary depending on the specific wavelength range being considered. This can also vary based on atmospheric conditions.

In summary, while the diffuse radiation on a North facing vertical face may be primarily from visible light, it will also include infrared radiation which carries heat energy. And while the percentage of visible light and infrared in the sun's energy output may vary, both can contribute to heating a house. It is important to take into account all types of solar radiation when assessing the potential for solar heating.
 

1. What is atmospheric radiation scattering/absorption?

Atmospheric radiation scattering/absorption refers to the process by which particles and gases in the Earth's atmosphere interact with incoming solar radiation. This interaction can result in the scattering or absorption of the radiation, affecting the amount of energy that reaches the Earth's surface.

2. How does atmospheric composition affect radiation scattering/absorption?

The composition of the atmosphere, specifically the concentration of gases like water vapor, carbon dioxide, and ozone, can greatly impact the amount of radiation that is scattered or absorbed. These gases have unique properties that allow them to interact with radiation in different ways.

3. What is the role of clouds in atmospheric radiation scattering/absorption?

Clouds play a significant role in atmospheric radiation scattering/absorption. They can act as both scatterers and absorbers of radiation, depending on their thickness and composition. Low, thick clouds tend to absorb more radiation, while high, thin clouds tend to scatter more radiation.

4. How does atmospheric radiation scattering/absorption contribute to the Earth's climate?

The amount of radiation that is scattered or absorbed by the atmosphere greatly affects the Earth's climate. When there is an imbalance between incoming and outgoing radiation, it can lead to changes in temperature and weather patterns. The greenhouse effect, caused by certain gases absorbing and re-emitting radiation, is an example of how atmospheric radiation scattering/absorption can impact the Earth's climate.

5. What are some techniques used to study atmospheric radiation scattering/absorption?

Scientists use a variety of techniques to study atmospheric radiation scattering/absorption, including satellite remote sensing, ground-based measurements, and computer modeling. These methods allow for a better understanding of how radiation interacts with the atmosphere and how it impacts the Earth's climate.

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