Solar energy to the Earth - Revision history

Dylan.Chung: /* Energy Absorbed by the Earth */

2026-03-11T19:43:55Z

Energy Absorbed by the Earth

← Older revision		Revision as of 19:43, 11 March 2026
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	Due to reflection by the atmosphere, clouds, and Earth's surface we can approximate that 70% of solar energy incident on the edge of the Earth's atmosphere is actually absorbed by the Earth. Taking this into account, the actual average amount of solar energy absorbed by the Earth amounts to:		Due to reflection by the atmosphere, clouds, and Earth's surface we can approximate that 70% of solar energy incident on the edge of the Earth's atmosphere is actually absorbed by the Earth. Taking this into account, the actual average amount of solar energy absorbed by the Earth amounts to:

	<center><math>H=0.7\times 340 \frac{W}{m^2} = 238 \frac{W}{m^2}</math></~~center~~>		<div style="text-align: center;"><math>H=0.7\times 340 \frac{W}{m^2} = 238 \frac{W}{m^2}</math></div>

	===Energy to the Surface===		===Energy to the Surface===

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:42:14Z

Energy from Sun to Earth

← Older revision		Revision as of 19:42, 11 March 2026
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	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

	<div ~~class="center"~~ style="~~width: auto; margin~~-~~left~~: ~~auto; margin-right: auto~~;">		<div style="text-align: center;">
	<math display="inline">I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math display="inline">I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	</div>		</div>

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:40:45Z

Energy from Sun to Earth

← Older revision		Revision as of 19:40, 11 March 2026
Line 10:		Line 10:

	<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math display="inline">I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	</div>		</div>

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:38:21Z

Energy from Sun to Earth

← Older revision		Revision as of 19:38, 11 March 2026
Line 9:		Line 9:
	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

	<div class="center";>		<div class="center" style="width: auto; margin-left: auto; margin-right: auto;">
	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	</div>		</div>

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:36:27Z

Energy from Sun to Earth

← Older revision		Revision as of 19:36, 11 March 2026
Line 9:		Line 9:
	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

	<div ~~style~~=~~text-align:~~ center;>		<div class="center";>
	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	</div>		</div>

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:34:41Z

Energy from Sun to Earth

← Older revision		Revision as of 19:34, 11 March 2026
Line 9:		Line 9:
	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

	<div style=~~text_align~~: center;>		<div style=text-align: center;>
	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	</div>		</div>

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:33:42Z

Energy from Sun to Earth

← Older revision		Revision as of 19:33, 11 March 2026
Line 9:		Line 9:
	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

			<div style=text_align: center;>
	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
	~~{{center\|<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}~~</~~math~~>}}		</div>


	To determine the average amount of solar energy that reaches the Earth, we must consider what the Earth "looks like" to the Sun. When looking at Earth from the Sun, only one half of the Earth can be seen. Thus to make an appropriate estimate of the average amount of solar energy over the entire surface area of the Earth the value for <math>I_{sc}</math> must be divided by 2.		To determine the average amount of solar energy that reaches the Earth, we must consider what the Earth "looks like" to the Sun. When looking at Earth from the Sun, only one half of the Earth can be seen. Thus to make an appropriate estimate of the average amount of solar energy over the entire surface area of the Earth the value for <math>I_{sc}</math> must be divided by 2.

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:29:02Z

Energy from Sun to Earth

← Older revision		Revision as of 19:29, 11 March 2026
Line 10:		Line 10:

	<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>
			{{center\|<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>}}

Dylan.Chung: /* Energy from Sun to Earth */

2026-03-11T19:27:56Z

Energy from Sun to Earth

← Older revision		Revision as of 19:27, 11 March 2026
Line 9:		Line 9:
	The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:		The Sun is generally considered to produce a constant amount of [[power]] (although there are small variances in the output energy depending on sunspot cycles) with a surface intensity of <math>6.33 \times 10^7 \frac{W}{m^2} </math>, expressed in units of power per unit area. As the Sun's rays spread into space this radiation becomes less and less intense as an [[inverse square law]].<ref name="RE1">ITACA. (April 4, 2015). ''The Sun as a Source of Energy'' [Online]. Available: http://www.itacanet.org/the-sun-as-a-source-of-energy/part-2-solar-energy-reaching-the-earths-surface/</ref> The average [[radiation]] intensity that hits the edge of the Earth's atmosphere is known as the '''solar constant''', or <math>I_{sc}</math>. Although this value is called a constant it varies by about 7% between January 4th (perihelion), when the Earth is closest to the sun, and July 4th (aphelion), when the Earth is furthest away.<ref>For some fun information on perihelion and aperihelion see NASA's page (accessed April 20th, 2015): https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2517</ref> Therefore a yearly average is used and is determined to be <math>1367 \frac{W}{m^2}</math>.<ref name="RE1"/> To determine this value from solar flux, the distance from the Earth to the Sun is used. As well, the total solar flux - not solar flux per unit area - must be determined. Then the total solar flux from the Sun is divided by the surface area of a sphere that has a radius equal to the distance from the Earth to the Sun. This accounts for the "spreading" of the solar energy. The expression to determine this value is:

	~~<center>~~<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math~~></center~~>		<math>I_{sc}=\frac{(6.33 \times 10^7 \frac{W}{m^2})(Surface\;Area\;of\;Sun\;)}{4\pi(Distance\;from\;Earth\;to\;Sun)^2}</math>

Jmdonev at 20:47, 3 May 2023

2023-05-03T20:47:33Z

← Older revision		Revision as of 20:47, 3 May 2023
Line 29:		Line 29:
	Energy that is absorbed by the Earth is not the same as the energy incident on the Earth's surface. On a perfectly clear or cloudless day, when the Sun is directly overhead (or at the "zenith"), solar irradiation is still reduced due to absorption (16%) and reflection (6%) by particles in Earth's atmosphere. These particles include carbon dioxide (CO<sub>2</sub>), Oxygen (O<sub>2</sub>), Ozone (O<sub>3</sub>) and water vapor (H<sub>2</sub>O).<ref name=Chen>C. Julian Chen. (April 13, 2018). Physics of Solar Energy, 1st ed. Hoboken, NJ, USA.: John Wiley & Sons, 2011</ref>		Energy that is absorbed by the Earth is not the same as the energy incident on the Earth's surface. On a perfectly clear or cloudless day, when the Sun is directly overhead (or at the "zenith"), solar irradiation is still reduced due to absorption (16%) and reflection (6%) by particles in Earth's atmosphere. These particles include carbon dioxide (CO<sub>2</sub>), Oxygen (O<sub>2</sub>), Ozone (O<sub>3</sub>) and water vapor (H<sub>2</sub>O).<ref name=Chen>C. Julian Chen. (April 13, 2018). Physics of Solar Energy, 1st ed. Hoboken, NJ, USA.: John Wiley & Sons, 2011</ref>

	[[File:~~Solar_Spectrum~~.png\|400px\|thumb\|center\|Figure 4. Solar radiation spectrum for direct light at both the top of the Earth's atmosphere and at sea level.<ref>Wikimedia Commons. (April 16, 2018). ''Solar Spectrum'' [Online]. Available: https://commons.wikimedia.org/wiki/File:Solar_Spectrum.png</ref>]]		[[File:SolarBlackbody.png\|400px\|thumb\|center\|Figure 4. Solar radiation spectrum for direct light at both the top of the Earth's atmosphere and at sea level.<ref>Wikimedia Commons. (April 16, 2018). ''Solar Spectrum'' [Online]. Available: https://commons.wikimedia.org/wiki/File:Solar_Spectrum.png</ref>]]
	This 22% reduction of solar irradiation will be higher on average because the Sun is not always at the zenith. To standardize this measurement, a unit called '''Air Mass''' is used to define the [[solar spectrum]] that is incident at various altitudes and conditions on Earth. Air Mass 0, or AM0 spectrum is the solar radiation outside the atmosphere and represents a power density of <math>1367\frac{W}{m^2}</math>. AM1.5 is regarded as "normal" air mass and represents a power density of <math>1000\frac{W}{m^2}</math>.<ref name=Chen></ref>		This 22% reduction of solar irradiation will be higher on average because the Sun is not always at the zenith. To standardize this measurement, a unit called '''Air Mass''' is used to define the [[solar spectrum]] that is incident at various altitudes and conditions on Earth. Air Mass 0, or AM0 spectrum is the solar radiation outside the atmosphere and represents a power density of <math>1367\frac{W}{m^2}</math>. AM1.5 is regarded as "normal" air mass and represents a power density of <math>1000\frac{W}{m^2}</math>.<ref name=Chen></ref>