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thorium1010
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So my question which part of the Em spectrum(sun) is responsible for heating of the atmosphere ? Is it visible or infrared or both ?
mfb said:All parts contribute, infrared more than visible light.
russ_watters said:Does the ground count here or are you just wondering about what frequencies of light it absorbs?
You are confusing heat with thermodynamic energy. Heat is energy other than work that is transferred between a system and the environment that surrounds it. Radiative heat transfer is one of the mechanisms by which a system exchanges energy other than work (i.e., heat) with its surrounding environment.Algr said:It is important to remember that "Heat" and "Infrared" are totally different things. "Heat" is the vibration of molecules. Since there are (almost) no molecules in space, heat cannot travel from the Sun to the Earth directly.
Because the atmosphere is more or less transparent to visible, less so to near infrared. The image below depicts solar radiation at the top of the atmosphere versus that at sea level. The difference between the two is incoming solar radiation that is either absorbed by the atmosphere or reflected back into space by the atmosphere or clouds. Only 19% of the incoming solar radiation is absorbed by the atmosphere; 30% is reflected back into space.thorium1010 said:But, why does infrared contribute more compared to visible ?
That is why air at high altitudes is so cold - the photons pass through without heating the air, and the ground is too far away
Algr said:So the short answer to thorium1010's question is that the ground heats the lower atmosphere, (troposphere) and UV and X-rays heat the parts above the ozone layer?
Chestermiller said:The solar spectrum is such that most of the heating by direct absorption of solar photons by atmospheric gases occurs in the UV (oxygen) and in the visible (ozone).
Your numbers don't add up to the solar "constant" of ~1.3kW/m^2.klimatos said:Of the 31 Watts per square meter of ultraviolet radiation that reaches the outside of the Earth's atmosphere from the Sun, only 5 Watts reaches the surface of the Earth. Most of the remaining 26 Watts is scattered by the atmosphere, but a small amount is absorbed--primarily by ozone and oxygen. Of the 154 Watts of visible sunlight at the outside of the atmosphere, 88 Watts reaches the surface. Most of the remaining 66 Watts is absorbed by clouds and particulates and the rest is scattered. Some of this scattered visible light reaches the surface as "skylight". Of the 157 Watts of infrared solar radiation, some 70 Watts reaches the surface. Most of the remaining 87 Watts is absorbed by water vapor and other "greenhouse" gases.
mfb said:Your numbers don't add up to the solar "constant" of ~1.3kW/m^2.
The Sun is the ultimate source of energy for our planet. Sunlight is responsible for heating the Earth's surface, which in turn heats the atmosphere.
The Earth's atmosphere is composed of various gases, such as oxygen, nitrogen, and water vapor, which are capable of absorbing sunlight. These gases absorb different wavelengths of sunlight, converting them into heat energy and warming the atmosphere.
Yes, the Earth's surface absorbs sunlight and then releases it as heat, which warms the lower layers of the atmosphere. This process is known as conduction. Convection also plays a role, as the heated air rises and cools, releasing heat energy into the surrounding atmosphere.
The Earth's surface is warmed by direct contact with sunlight, while the atmosphere is warmed through conduction and convection. As you move further away from the surface, there is less direct contact with sunlight, resulting in a decrease in temperature. Additionally, the atmosphere is thinner at higher altitudes, making it easier for heat to escape into space.
The Sun's energy is the driving force behind weather patterns. The heating of the atmosphere creates differences in air pressure, which leads to the movement of air and the formation of winds. These winds, along with other factors, contribute to the development of various weather systems and patterns.