North Atlantic Oscillation - Revision history

Jmdonev at 20:58, 25 July 2023

2023-07-25T20:58:22Z

← Older revision		Revision as of 20:58, 25 July 2023
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	[[Category:Done ~~2017~~-07-01]]		[[Category:Done 2022-12-31]]
	[[File:NAO_Schematic_0.png\|thumb\|400px\|right\|Figure 1. This image illustrates the surface pressure in both negative and positive modes of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]		[[File:NAO_Schematic_0.png\|thumb\|400px\|right\|Figure 1. This image illustrates the surface pressure in both negative and positive modes of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
	<onlyinclude>'''North Atlantic Oscillation''' (NAO) is a [[climate]] pattern that has a strong influence over North America, Greenland, and Europe.<ref name="RE1">"Climate Variability: North Atlantic Oscillation \| NOAA Climate.gov", Climate.gov, 2016. [Online]. Available: https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation. [Accessed: 18- May- 2016].</ref> The NAO is a [[Modes of climate variability\|natural form of climate variability]], explaining short and long phases in climate caused by natural, large scale features. Other natural patterns of climate variability include the [[Northern Annular Mode]], [[Pacific Decadal Oscillation]], and the [[Atlantic Multidecadal Oscillation]]. The NAO forms a permanent low [[pressure]] system which exists over Greenland and Iceland, with ~~a permanent~~ high-pressure system existing over a group of islands roughly 1400 k[[meter\|m]] west of Portugal, known as the Azores.<ref name=RE3>”Searching for Atlantic Rhythms? : Feature Articles", NASA, 2016. [Online]. Available: http://earthobservatory.nasa.gov/Features/NAO/. [Accessed: 19- May- 2016].</ref></onlyinclude> For most of the year, the high and the low are mild, and their influence on the Atlantic basin climate is minimal. However, when winter enters, all of this begins to change. Both pressure systems grow much more intense and begin to fluctuate from week to week between the two different states. In one state, the positive NAO, the high-pressure system grows especially high. While the second state, a negative NAO, a low-pressure system grows especially low, creating a large pressure difference between the Azores and Iceland.<ref name=RE3/>		<onlyinclude>'''North Atlantic Oscillation''' (NAO) is a [[climate]] pattern that has a strong influence over North America, Greenland, and Europe.<ref name="RE1">"Climate Variability: North Atlantic Oscillation \| NOAA Climate.gov", Climate.gov, 2016. [Online]. Available: https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation. [Accessed: 18- May- 2016].</ref> The NAO is a [[Modes of climate variability\|natural form of climate variability]], explaining short and long phases in climate caused by natural, large scale features. Other natural patterns of climate variability include the [[Northern Annular Mode]], [[Pacific Decadal Oscillation]], and the [[Atlantic Multidecadal Oscillation]]. The NAO forms a permanent low [[pressure]] system which exists over Greenland and Iceland, with an ongoing high-pressure system existing over a group of islands roughly 1400 [[meter\|km]] west of Portugal, known as the Azores.<ref name=RE3>”Searching for Atlantic Rhythms? : Feature Articles", NASA, 2016. [Online]. Available: http://earthobservatory.nasa.gov/Features/NAO/. [Accessed: 19- May- 2016].</ref></onlyinclude> For most of the year, the high and the low are mild, and their influence on the Atlantic basin climate is minimal. However, when winter enters, all of this begins to change. Both pressure systems grow much more intense and begin to fluctuate from week to week between the two different states. In one state, the positive NAO, the high-pressure system grows especially high. While the second state, a negative NAO, a low-pressure system grows especially low, creating a large pressure difference between the Azores and Iceland.<ref name=RE3/>

	The influence of the NAO and its phases can be felt across the entire Atlantic Ocean and the surrounding continents. Between the two circulating, clockwise and counterclockwise circulation patterns created by the high and low systems, there is an area where they come together and form a steady, forward moving current that channels [[weather]] systems from the United States to Europe.<ref name=RE3/> To understand the NAO, first understanding what air pressure means is important.		The influence of the NAO and its phases can be felt across the entire Atlantic Ocean and the surrounding continents. Between the two circulating, clockwise and counterclockwise circulation patterns created by the high and low systems, there is an area where they come together and form a steady, forward moving current that channels [[weather]] systems from the United States to Europe.<ref name=RE3/> To understand the NAO, first understanding what air pressure means is important.

	[[Air pressure]] is a measure of how much air is pushing down on the surface of the [[Earth]] at any given point.<ref name=RE3/> Normally, high and low pressure systems form when air mass and [[temperature]] differences between the surface of the Earth and the upper [[atmosphere]] produce vertical winds (more correctly vertical currents). In a low pressure system, these vertical winds travel upwards and pull air away from the surface of the [[Earth]], decreasing the [[air pressure]] above the ground or sea.<ref name=RE3/> In contrast, in a [[high-pressure system]], air is being pushed down. The higher in pressure a high-pressure system gets or the lower in pressure a low pressure system gets, the more intense and larger the spinning circulation pattern becomes.<ref name=RE3/>		[[Air pressure]] is a measure of how much air is pushing down on the surface of the [[Earth]] at any given point.<ref name=RE3/> Normally, high and low pressure systems form when air mass and [[temperature]] differences between the surface of the Earth and the upper [[atmosphere]] produce vertical winds (more correctly vertical currents). In a low pressure system, these vertical winds travel upwards and pull air away from the surface of the [[Earth]], decreasing the air pressure above the ground or sea.<ref name=RE3/> In contrast, in a [[high-pressure system]], air is being pushed down. The higher in pressure a high-pressure system gets or the lower in pressure a low pressure system gets, the more intense and larger the spinning circulation pattern becomes.<ref name=RE3/>

	Researchers have had relative success with short term forecasts by linking the NAO to [[sea surface temperature]]s through statistical correlation, and over a longer time frame, they have discovered that [[global warming]] may be slowly influencing the strength of the NAO and its effect on the [[climate]].<ref name=RE3/>		Researchers have had relative success with short term forecasts by linking the NAO to [[sea surface temperature]]s through statistical correlation, and over a longer time frame, they have discovered that [[global warming]] may be slowly influencing the strength of the NAO and its effect on the [[climate]].<ref name=RE3/>
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	===Positive NAO===		===Positive NAO===
	[[File:NAO Positive.png\|thumb\|350px\|right\|Figure 1. This image illustrates the surface pressure in the positive mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]		[[File:NAO Positive.png\|thumb\|350px\|right\|Figure 1. This image illustrates the surface pressure in the positive mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
	:The NAO is in a positive phase when both the sub polar low and the subtropical high are stronger than average. During positive NAO phases, the increased difference in pressure between the two regions results in a stronger Atlantic [[jet stream]] and a northward shift of the [[storm track]]. Consequently, northern Europe experiences increased [[storm]]iness and [[precipitation]], and warmer than average temperatures that are associated with the air masses that arrive from lower latitudes. At the same time, southern Europe experiences decreased storminess and below average precipitation. In eastern North America, the positive phase of the NAO generally brings higher air ~~pressure near the Azores~~.<ref name=RE3/> This causes less snowfall for the Washington DC/New York corridor.		:The NAO is considered to be in a positive phase when both the sub polar low and the subtropical high are stronger than average. During positive NAO phases, the increased difference in pressure between the two regions results in a stronger Atlantic [[jet stream]] and a northward shift of the [[storm track]]. Consequently, northern Europe experiences increased [[storm]]iness and [[precipitation]], and warmer than average temperatures that are associated with the air masses that arrive from lower latitudes. At the same time, southern Europe experiences decreased storminess and below average precipitation. In eastern North America, the positive phase of the NAO generally brings higher air pressures.<ref name=RE3/> This causes less snowfall for the Washington DC/New York corridor.<ref name=RE3/>




	===Negative NAO===		===Negative NAO===
	[[File:NAO Negative.png\|thumb\|350px\|right\|Figure 2. This image illustrates the surface pressure in the negative mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]		[[File:NAO Negative.png\|thumb\|350px\|right\|Figure 2. This image illustrates the surface pressure in the negative mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
	:The NAO is in a negative phase when both the sub polar low and the subtropical high are weaker than average. During negative NAO phases, the Atlantic jet stream has a more west to east orientation, and this brings decreased storminess, below average precipitation, and lower than average temperatures to northern Europe. In contrast, Southern Europe experiences increased storminess, above average precipitation, and warmer than average temperatures. In eastern North America, the negative phase of NAO generally brings lower air pressure, which leads to winter storms, and cold weather ~~that~~ are normally meant for Boston and Maine to start heading south.<ref name=RE3/>		:The NAO is in a negative phase when both the sub polar low and the subtropical high are weaker than average. During negative NAO phases, the Atlantic jet stream has a more west to east orientation, and this brings decreased storminess, below average precipitation, and lower than average temperatures to northern Europe. In contrast, Southern Europe experiences increased storminess, above average precipitation, and warmer than average temperatures. In eastern North America, the negative phase of NAO generally brings lower air pressure, which leads to winter storms, and cold weather, which are normally meant for Boston and Maine, to start heading south.<ref name=RE3/>





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

Jmdonev: 1 revision imported

2017-08-29T01:46:53Z

1 revision imported

← Older revision	Revision as of 01:46, 29 August 2017
(No difference)

Jmdonev at 17:39, 28 July 2017

2017-07-28T17:39:50Z

← Older revision		Revision as of 17:39, 28 July 2017
Line 1:		Line 1:
	[[Category:Done ~~2016~~-04-30]]		[[Category:Done 2017-07-01]]
	[[File:NAO_Schematic_0.png\|thumb\|400px\|right\|Figure 1. This image illustrates the surface pressure in both negative and positive modes of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]		[[File:NAO_Schematic_0.png\|thumb\|400px\|right\|Figure 1. This image illustrates the surface pressure in both negative and positive modes of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
	<onlyinclude>'''North Atlantic Oscillation''' (NAO) is a [[climate]] pattern that has a strong influence over North America, Greenland, and Europe.<ref name="RE1">"Climate Variability: North Atlantic Oscillation \| NOAA Climate.gov", Climate.gov, 2016. [Online]. Available: https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation. [Accessed: 18- May- 2016].</ref> The NAO is a [[Modes of climate variability\|natural form of climate variability]], explaining short and long phases in climate caused by natural, large scale features. Other natural patterns of climate variability include the [[Northern Annular Mode]], [[Pacific Decadal Oscillation]], and the [[Atlantic Multidecadal Oscillation]]. The NAO forms a permanent low [[pressure]] system which exists over Greenland and Iceland, with a permanent high pressure system existing over a group of islands roughly 1400 k[[m]] west of Portugal, known as the Azores.<ref name=RE3>”Searching for Atlantic Rhythms? : Feature Articles", NASA, 2016. [Online]. Available: http://earthobservatory.nasa.gov/Features/NAO/. [Accessed: 19- May- 2016].</ref></onlyinclude> For most of the year, the high and the low are mild, and their influence on the Atlantic basin climate is minimal. However, when winter enters, all of this begins to change. Both pressure systems grow much more intense and begin to fluctuate from week to week between the two different states. In one state, the positive NAO, the high-pressure system grows especially high. While the second state, a negative NAO, a low-pressure system grows especially low, creating a large pressure difference between the Azores and Iceland.<ref name=RE3/>		<onlyinclude>'''North Atlantic Oscillation''' (NAO) is a [[climate]] pattern that has a strong influence over North America, Greenland, and Europe.<ref name="RE1">"Climate Variability: North Atlantic Oscillation \| NOAA Climate.gov", Climate.gov, 2016. [Online]. Available: https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation. [Accessed: 18- May- 2016].</ref> The NAO is a [[Modes of climate variability\|natural form of climate variability]], explaining short and long phases in climate caused by natural, large scale features. Other natural patterns of climate variability include the [[Northern Annular Mode]], [[Pacific Decadal Oscillation]], and the [[Atlantic Multidecadal Oscillation]]. The NAO forms a permanent low [[pressure]] system which exists over Greenland and Iceland, with a permanent high-pressure system existing over a group of islands roughly 1400 k[[meter\|m]] west of Portugal, known as the Azores.<ref name=RE3>”Searching for Atlantic Rhythms? : Feature Articles", NASA, 2016. [Online]. Available: http://earthobservatory.nasa.gov/Features/NAO/. [Accessed: 19- May- 2016].</ref></onlyinclude> For most of the year, the high and the low are mild, and their influence on the Atlantic basin climate is minimal. However, when winter enters, all of this begins to change. Both pressure systems grow much more intense and begin to fluctuate from week to week between the two different states. In one state, the positive NAO, the high-pressure system grows especially high. While the second state, a negative NAO, a low-pressure system grows especially low, creating a large pressure difference between the Azores and Iceland.<ref name=RE3/>

	The influence of the NAO and its phases can be felt across the entire Atlantic Ocean and the surrounding continents. Between the two circulating, clockwise and counterclockwise circulation patterns created by the high and low systems, there is an area where they come together and form a steady, forward moving current that channels [[weather]] systems from the United States to Europe.<ref name=RE3/> To understand the NAO, first understanding what air pressure means is important.		The influence of the NAO and its phases can be felt across the entire Atlantic Ocean and the surrounding continents. Between the two circulating, clockwise and counterclockwise circulation patterns created by the high and low systems, there is an area where they come together and form a steady, forward moving current that channels [[weather]] systems from the United States to Europe.<ref name=RE3/> To understand the NAO, first understanding what air pressure means is important.

	[[Air pressure]] is a measure of how much air is pushing down on the surface of the [[Earth]] at any given point.<ref name=RE3/> Normally, high and low pressure systems form when air mass and [[temperature]] differences between the surface of the Earth and the upper [[atmosphere]] produce vertical winds (more correctly vertical currents). In a low pressure system, these vertical winds travel upwards and pull air away from the surface of the [[Earth]], decreasing the [[air pressure]] above the ground or sea.<ref name=RE3/> In contrast, in a [[high pressure system]], air is being pushed down. The higher in pressure a high pressure system gets or the lower in pressure a low pressure system gets, the more intense and larger the spinning circulation pattern becomes.<ref name=RE3/>		[[Air pressure]] is a measure of how much air is pushing down on the surface of the [[Earth]] at any given point.<ref name=RE3/> Normally, high and low pressure systems form when air mass and [[temperature]] differences between the surface of the Earth and the upper [[atmosphere]] produce vertical winds (more correctly vertical currents). In a low pressure system, these vertical winds travel upwards and pull air away from the surface of the [[Earth]], decreasing the [[air pressure]] above the ground or sea.<ref name=RE3/> In contrast, in a [[high-pressure system]], air is being pushed down. The higher in pressure a high-pressure system gets or the lower in pressure a low pressure system gets, the more intense and larger the spinning circulation pattern becomes.<ref name=RE3/>

	Researchers have had relative success with short term forecasts by linking the NAO to [[sea surface temperature]]s through statistical correlation, and over a longer time frame, they have discovered that [[global warming]] may be slowly influencing the strength of the NAO and its effect on the [[climate]].<ref name=RE3/>		Researchers have had relative success with short term forecasts by linking the NAO to [[sea surface temperature]]s through statistical correlation, and over a longer time frame, they have discovered that [[global warming]] may be slowly influencing the strength of the NAO and its effect on the [[climate]].<ref name=RE3/>

Jmdonev: 1 revision imported: From the summer

2016-09-17T22:29:35Z

1 revision imported: From the summer

← Older revision	Revision as of 22:29, 17 September 2016
(No difference)

Jmdonev at 21:44, 1 August 2016

2016-08-01T21:44:24Z

New page

[[Category:Done 2016-04-30]]
[[File:NAO_Schematic_0.png|thumb|400px|right|Figure 1. This image illustrates the surface pressure in both negative and positive modes of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
<onlyinclude>'''North Atlantic Oscillation''' (NAO) is a [[climate]] pattern that has a strong influence over North America, Greenland, and Europe.<ref name="RE1">"Climate Variability: North Atlantic Oscillation | NOAA Climate.gov", Climate.gov, 2016. [Online]. Available: https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation. [Accessed: 18- May- 2016].</ref> The NAO is a [[Modes of climate variability|natural form of climate variability]], explaining short and long phases in climate caused by natural, large scale features. Other natural patterns of climate variability include the [[Northern Annular Mode]], [[Pacific Decadal Oscillation]], and the [[Atlantic Multidecadal Oscillation]]. The NAO forms a permanent low [[pressure]] system which exists over Greenland and Iceland, with a permanent high pressure system existing over a group of islands roughly 1400 k[[m]] west of Portugal, known as the Azores.<ref name=RE3>”Searching for Atlantic Rhythms? : Feature Articles", NASA, 2016. [Online]. Available: http://earthobservatory.nasa.gov/Features/NAO/. [Accessed: 19- May- 2016].</ref></onlyinclude> For most of the year, the high and the low are mild, and their influence on the Atlantic basin climate is minimal. However, when winter enters, all of this begins to change. Both pressure systems grow much more intense and begin to fluctuate from week to week between the two different states. In one state, the positive NAO, the high-pressure system grows especially high. While the second state, a negative NAO, a low-pressure system grows especially low, creating a large pressure difference between the Azores and Iceland.<ref name=RE3/>

The influence of the NAO and its phases can be felt across the entire Atlantic Ocean and the surrounding continents. Between the two circulating, clockwise and counterclockwise circulation patterns created by the high and low systems, there is an area where they come together and form a steady, forward moving current that channels [[weather]] systems from the United States to Europe.<ref name=RE3/> To understand the NAO, first understanding what air pressure means is important.

[[Air pressure]] is a measure of how much air is pushing down on the surface of the [[Earth]] at any given point.<ref name=RE3/> Normally, high and low pressure systems form when air mass and [[temperature]] differences between the surface of the Earth and the upper [[atmosphere]] produce vertical winds (more correctly vertical currents). In a low pressure system, these vertical winds travel upwards and pull air away from the surface of the [[Earth]], decreasing the [[air pressure]] above the ground or sea.<ref name=RE3/> In contrast, in a [[high pressure system]], air is being pushed down. The higher in pressure a high pressure system gets or the lower in pressure a low pressure system gets, the more intense and larger the spinning circulation pattern becomes.<ref name=RE3/>

Researchers have had relative success with short term forecasts by linking the NAO to [[sea surface temperature]]s through statistical correlation, and over a longer time frame, they have discovered that [[global warming]] may be slowly influencing the strength of the NAO and its effect on the [[climate]].<ref name=RE3/>

==Phases of NAO==

===Positive NAO===
[[File:NAO Positive.png|thumb|350px|right|Figure 1. This image illustrates the surface pressure in the positive mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
:The NAO is in a positive phase when both the sub polar low and the subtropical high are stronger than average. During positive NAO phases, the increased difference in pressure between the two regions results in a stronger Atlantic [[jet stream]] and a northward shift of the [[storm track]]. Consequently, northern Europe experiences increased [[storm]]iness and [[precipitation]], and warmer than average temperatures that are associated with the air masses that arrive from lower latitudes. At the same time, southern Europe experiences decreased storminess and below average precipitation. In eastern North America, the positive phase of the NAO generally brings higher air pressure near the Azores.<ref name=RE3/> This causes less snowfall for the Washington DC/New York corridor.

===Negative NAO===
[[File:NAO Negative.png|thumb|350px|right|Figure 2. This image illustrates the surface pressure in the negative mode of the North Atlantic Oscillation.<ref>National Oceanic and Atmospheric Administration. (July 22, 2016). ‘’NAO Modes’’ [Online]. Available: https://www.climate.gov/sites/default/files/NAO_Schematic_0.png</ref>]]
:The NAO is in a negative phase when both the sub polar low and the subtropical high are weaker than average. During negative NAO phases, the Atlantic jet stream has a more west to east orientation, and this brings decreased storminess, below average precipitation, and lower than average temperatures to northern Europe. In contrast, Southern Europe experiences increased storminess, above average precipitation, and warmer than average temperatures. In eastern North America, the negative phase of NAO generally brings lower air pressure, which leads to winter storms, and cold weather that are normally meant for Boston and Maine to start heading south.<ref name=RE3/>

==References==
{{reflist}}