Prevailing winds - Revision history

Jmdonev at 22:18, 4 January 2019

2019-01-04T22:18:44Z

← Older revision		Revision as of 22:18, 4 January 2019
Line 1:		Line 1:
	[[Category:Done ~~2015~~-09-06]]		[[Category:Done 2018-12-10]] [[Category: Rudi grade Ashley edit]]
	<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>		<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>

	Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds ~~as well~~.		Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds.

	==How ~~they are formed~~==		==How They Form==
	The ~~sun heats up~~ the ~~area around~~ the equator ~~because it shines so directly down on the Earth there~~. As seen in ~~figure~~ 1, ~~this~~ expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As ~~this~~ air rises, it cools, ~~this makes~~ the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north ~~and~~ south. ~~However the~~ wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.		The equator receives the most direct sunlight, resulting in the planet's warmest temperatures being near the equator. As seen in Figure 1, heat expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As the air rises, it cools, making the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north or south. The wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.

	[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]		[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]

	The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing ~~upwards~~ and ~~downwards~~ from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.		The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing up and away from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.

	Not all of the air moves back towards the equator ~~however, and some continues towards~~ the ~~poles, until it~~ reaches ~~the~~ 60 ~~degree~~ latitude ~~where~~ it meets cold air from the poles. These winds are known as the '''~~westerlies~~'''. At this point, the warm air rises and most flows back towards the 30 degree latitude. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>		Not all of the air moves back towards the equator though. When the air reaches approximately 60 degrees latitude (North or South), it meets cold air from the poles. These winds are known as the '''Westerlies'''. At this point, the warm air rises and most of it flows back towards the 30 degree latitude mark. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>

	The final regions are at the poles, from ~~the~~ 60 ~~degree~~ latitude to ~~the~~ 90 ~~degree latitudes~~. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what ~~are~~ known as the '''~~polar~~ Hadley cell''' or '''~~polar~~ cell'''.<Ref name=boyle/>		The final regions are at the poles, from 60 degrees latitude to 90 degrees latitude. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what is known as the '''Polar Hadley cell''' or '''Polar cell'''.<Ref name=boyle/>

	~~The video from [https://www.miracosta.edu/home/kmeldahl/ Keith Meldahl] below illustrates each of the described winds, along with a visualization of each.~~

			The video from [https://www.miracosta.edu/home/kmeldahl/ Keith Meldahl]<ref>Keith Meldahl made the video, but the animation is a property of Pearson publication and is connected to the textbook "Essentials of Oceanography" by Trujillo and Thurman, published 2014.</ref> below illustrates each of the described winds, along with a visualization of each.

	<html>		<html>
	<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>		<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>
	</html>		</html>

			==For Further Reading==
			*[[Wind]]
			*[[Wind farm]]
			*[[Wind turbine]]
			*[[Electricity]]
			*[[Precipitation]]
			*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{Reflist}}		{{Reflist}}[[Category:Uploaded]]

Jmdonev: 1 revision imported

2019-01-04T18:15:21Z

1 revision imported

← Older revision	Revision as of 18:15, 4 January 2019
(No difference)

Jmdonev at 02:20, 2 December 2018

2018-12-02T02:20:12Z

← Older revision		Revision as of 02:20, 2 December 2018
Line 1:		Line 1:
	[[Category:Done ~~2018~~-12-~~10]] [[Category: Rudi grade Ashley edit~~]]		[[Category:Done 2015-09-06]]
	<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>		<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>

	Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds.		Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds as well.

	==How ~~They Form~~==		==How they are formed==
	The ~~equator receives~~ the ~~most direct sunlight, resulting in~~ the ~~planet's warmest temperatures being near~~ the ~~equator~~. As seen in ~~Figure~~ 1, ~~heat~~ expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As ~~the~~ air rises, it cools, ~~making~~ the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north or south. ~~The~~ wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.		The sun heats up the area around the equator because it shines so directly down on the Earth there. As seen in figure 1, this expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As this air rises, it cools, this makes the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north and south. However the wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.

	[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]		[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]

	The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing up and ~~away~~ from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.		The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing upwards and downwards from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.

	Not all of the air moves back towards the equator ~~though. When~~ the ~~air~~ reaches ~~approximately~~ 60 ~~degrees~~ latitude ~~(North or South),~~ it meets cold air from the poles. These winds are known as the '''~~Westerlies~~'''. At this point, the warm air rises and most ~~of it~~ flows back towards the 30 degree latitude ~~mark~~. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>		Not all of the air moves back towards the equator however, and some continues towards the poles, until it reaches the 60 degree latitude where it meets cold air from the poles. These winds are known as the '''westerlies'''. At this point, the warm air rises and most flows back towards the 30 degree latitude. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>

	The final regions are at the poles, from 60 ~~degrees~~ latitude to 90 ~~degrees latitude~~. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what is known as the '''~~Polar~~ Hadley cell''' or '''~~Polar~~ cell'''.<Ref name=boyle/>		The final regions are at the poles, from the 60 degree latitude to the 90 degree latitudes. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what are known as the '''polar Hadley cell''' or '''polar cell'''.<Ref name=boyle/>

	The video from [https://www.miracosta.edu/home/kmeldahl/ Keith Meldahl] below illustrates each of the described winds, along with a visualization of each.		The video from [https://www.miracosta.edu/home/kmeldahl/ Keith Meldahl] below illustrates each of the described winds, along with a visualization of each.


	<html>		<html>
	<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>		<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>
	</html>		</html>

	~~==For Further Reading==~~
	*[[Wind]]
	*[[Wind farm]]
	*[[Wind turbine]]
	*[[Electricity]]
	*[[Precipitation]]
	*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{Reflist}}~~[[Category:Uploaded]]~~		{{Reflist}}

2dev>Jmdonev at 02:17, 2 December 2018

2018-12-02T02:17:13Z

← Older revision		Revision as of 02:17, 2 December 2018
Line 1:		Line 1:
	[[Category:Done ~~2015~~-09-06]]		[[Category:Done 2018-12-10]] [[Category: Rudi grade Ashley edit]]
	<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>		<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>

	Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds ~~as well~~.		Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds.

	==How ~~they are formed~~==		==How They Form==
	The ~~sun heats up~~ the ~~area around~~ the equator ~~because it shines so directly down on the Earth there~~. As seen in ~~figure~~ 1, ~~this~~ expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As ~~this~~ air rises, it cools, ~~this makes~~ the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north ~~and~~ south. ~~However the~~ wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.		The equator receives the most direct sunlight, resulting in the planet's warmest temperatures being near the equator. As seen in Figure 1, heat expands the air, making it less [[density\|dense]] which leads to rising [[air]]. As the air rises, it cools, making the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north or south. The wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect\|Coriolis effect]]), which results in a variety of prevailing winds.

	[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]		[[File:prevailingwinds.png\|550px\|center\|thumb\|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]

	The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing ~~upwards~~ and ~~downwards~~ from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.		The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing up and away from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.

	Not all of the air moves back towards the equator ~~however, and some continues towards~~ the ~~poles, until it~~ reaches ~~the~~ 60 ~~degree~~ latitude ~~where~~ it meets cold air from the poles. These winds are known as the '''~~westerlies~~'''. At this point, the warm air rises and most flows back towards the 30 degree latitude. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>		Not all of the air moves back towards the equator though. When the air reaches approximately 60 degrees latitude (North or South), it meets cold air from the poles. These winds are known as the '''Westerlies'''. At this point, the warm air rises and most of it flows back towards the 30 degree latitude mark. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>

	The final regions are at the poles, from ~~the~~ 60 ~~degree~~ latitude to ~~the~~ 90 ~~degree latitudes~~. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what ~~are~~ known as the '''~~polar~~ Hadley cell''' or '''~~polar~~ cell'''.<Ref name=boyle/>		The final regions are at the poles, from 60 degrees latitude to 90 degrees latitude. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what is known as the '''Polar Hadley cell''' or '''Polar cell'''.<Ref name=boyle/>

	The video below illustrates each of the described winds, along with a visualization of each.		The video from [https://www.miracosta.edu/home/kmeldahl/ Keith Meldahl] below illustrates each of the described winds, along with a visualization of each.

	<html>		<html>
	<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>		<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>
	</html>		</html>

			==For Further Reading==
			*[[Wind]]
			*[[Wind farm]]
			*[[Wind turbine]]
			*[[Electricity]]
			*[[Precipitation]]
			*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{Reflist}}		{{Reflist}}[[Category:Uploaded]]

J.williams: 1 revision imported

2015-09-18T16:52:25Z

1 revision imported

← Older revision	Revision as of 16:52, 18 September 2015
(No difference)

Jmdonev at 19:11, 13 September 2015

2015-09-13T19:11:32Z

New page

[[Category:Done 2015-09-06]]
<onlyinclude>'''Prevailing winds''' are [[wind]]s that blow consistently in a given direction over a particular region on Earth.<ref name=env>Enviropedia. (August 24, 2015). ''Prevailing Winds'' [Online], Available: http://www.enviropedia.org.uk/Climate/Prevailing_Winds.php</ref> Due to factors such as uneven [[heat]]ing from the [[Sun]] and the Earth's rotation, these winds vary at different latitudes on Earth.</onlyinclude> Prevailing winds are important for determining locations of [[wind farm]]s in order to generate [[electricity]].<ref name=potts>G. Potts, ''Grand Bend Wind Farm,'' [Online], Available: http://grandbend.northlandpower.ca/site/northland_power___grand_bend_wind_farm/assets/pdf/npi_gbwf_10x12.5_pr02_aug30.pdf</ref>

Prevailing winds also determine the amount of [[rainfall]] that different regions get. In Southeastern Asia, these winds result in the formation of [[monsoon]]s and [[desert]]s. The West coast of South and North America receives abundant [[rain]] during the winter due to these winds as well.

==How they are formed==
The sun heats up the area around the equator because it shines so directly down on the Earth there. As seen in figure 1, this expands the air, making it less [[density|dense]] which leads to rising [[air]]. As this air rises, it cools, this makes the air lose its [[water vapour]] as rain. This air then circulates around to roughly 30 degrees north and south. However the wind doesn't flow directly up, because the Earth rotates. This rotation causes the wind to have a higher [[speed]] in the Eastern direction relative to the ground at high latitudes (see [[wind#Coriolis Effect|Coriolis effect]]), which results in a variety of prevailing winds.

[[File:prevailingwinds.png|550px|center|thumb|Figure 1. Prevailing winds and their corresponding cells. Refer to text below for more information.<ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/7/79/Atmospheric_circulation.svg</ref>]]

The '''trade winds''' seen in Figure 1 are created by hot [[air]] flowing upwards and downwards from the equator, where it gradually cools until it gets to latitudes of about 30 degrees. It then sinks down towards the surface and flows back towards the low-pressure zone at the equator. These flows are known as '''Hadley cells''', named after George Hadley who first described them in 1753.<ref name=boyle>G. Boyle. ''Renewable Energy: Power for a Sustainable Future'', 2nd ed. Oxford, UK: Oxford University Press, 2004.</ref> They are responsible for the dry weather patterns at the 30 degree latitudes, where the majority of the Earth's deserts lie.

Not all of the air moves back towards the equator however, and some continues towards the poles, until it reaches the 60 degree latitude where it meets cold air from the poles. These winds are known as the '''westerlies'''. At this point, the warm air rises and most flows back towards the 30 degree latitude. This creates the '''Ferrel cells''' of Figure 1.<ref name=boyle/>

The final regions are at the poles, from the 60 degree latitude to the 90 degree latitudes. This wind cools towards the poles and sinks to the surface, and recirculates. This creates what are known as the '''polar Hadley cell''' or '''polar cell'''.<Ref name=boyle/>

The video below illustrates each of the described winds, along with a visualization of each.

<html>
<iframe width="816" height="459" src="https://www.youtube.com/embed/Ye45DGkqUkE" frameborder="0" allowfullscreen></iframe>
</html>

==References==
{{Reflist}}