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Q 1 Why Polar Jet stream are strongest in comparison to Subtropical and Equatorial Jet Stream ? Q2 Why Polar Jet stream and Subtropical Jet Stream are flowing West to East whereas Equatorial Jet Streams are Easterlies ? Q3 How does Polar Jet Stream impact Global weathers Q4 How Polar Jet Streams are formed ?
Q 1 Why Polar Jet stream are strongest in comparison to Subtropical and Equatorial Jet Stream ? Q2 Why Polar Jet stream and Subtropical Jet Stream are flowing West to East whereas Equatorial Jet Streams are Easterlies ? Q3 How does Polar Jet Stream impact Global weathers Q4 How Polar Jet Streams are formed ?
i can tell u why jet streams occur and then we can derive the other answers from there.
- up in the atmosphere there will be pressure differences between two air masses. - The warmer air mass will be less dense and colder more dense, so the pressure difference. - now the air will try to move horizontally towards the lesser pressure, however, due to earth rotation it will not be able to fill up the less pressure and will move considerably straighter around the air masses. The heights at which these winds are strongest appear to form jet streams.u can see that these winds will be strongest where air mass temperature differ very much along the atmospheric height. Jet stream coz the jets can take advantage of these high speed winds if they follow the particular altitude.
now deriving some answers from this: u asked why the polar jet streams are strongest-- we can see that air masses difference here will be highest. For example, between the polar one and temperate one,,,,much more than equator and subtropical…
then u asked why they are flowing in certain directions --- this u shall be able to see with coriolis force as u do for normal winds on the ground,,,the upper winds are similarly affected by coriolis,,,
@trying_tobawesm thanx for ur answer using the basics I agree on the basic and strength part but some concerns on the direction of JS Regarding the directions of Jet Streams it isn't so straightforward answer consider the following facts as well Polar Jet Streams and Subtropical Jet streams are Westerly flowing Jetstreams whereas Equatorial Jetstream is easterly flowing Coriollis force can very well explain direction of Polar JS and Subtropical JS
however the big question remains Why Equatorial Jetstream is East flowing ?
This jet occurs in the northern summer between 10 and 20 deg N, chiefly over or just to the south of high land masses such as in Asia and Africa. Its occurrence is due to a temperature gradient with colder air to the south which produces sufficient temperature differential above 50 000 ft/15 km to give wind speeds of over 100 kt (50 m/s). Because colder temperatures at height are to the south, it is an easterly jet. (This jet is now more usually known as the Tropical Easterly Jet(TEJ) ... perhaps more correctly as it lies some distance from the Equator.)
c what they are saying is that colder temperatures are to the south,,,,perhaps this is happening due to movement of belts with respect to movement of sun,,as the hottest wll be north of equator during northern summers,,,so equator will be realtively colder,,,and coriolis shall take it to right and so when i go right from equator towards subtropical then the jet will go towards the east,,,,
Q4 How Polar Jet Streams are formed ? Ans: Due to interaction of cold polar easterlies and warm westerlies at surface. Air mass above cold easterlies which originated from Poles are cold, dense and heavy compare to air mass above warm easterlies brought by westerlies which is warm and rarefied. So, in upper atmosphere pressure above warm westerlies decrease slowly while pressure above cold polar easterlies decrease very rapidly. Due to this at the top intense pressure gradient will develop and very strong moving winds will flow in upper atmosphere. due to corollis force very fast moving wind will move right in northern hemisphere and left in souther hemisphere which is known as polar front jet stream. Hence direction is west to east in both the hemisphere (Ans to part of Q2 also)
Q2 Why Polar Jet stream and Subtropical Jet Stream are flowing West to East whereas Equatorial Jet Streams are Easterlies ?
@upsc_cracker where have you seen equatorial jet stream, it should be tropical easterly jet stream. kindly confirm and then I will tell why it is moving from east to west.
As far as the greater strength of polar jet in comparison to subtropical jet is concerned, it is because of greater thermal gradient in higher latitudes than lower in upper troposphere.
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Comments
Q5) Why do Jet Streams meander and don't follow straight line path ?
The last question Q5 is about Jet Streams in general ?
for others I have specified the Jet streams
- up in the atmosphere there will be pressure differences between two air masses.
- The warmer air mass will be less dense and colder more dense, so the pressure difference.
- now the air will try to move horizontally towards the lesser pressure, however, due to earth rotation it will not be able to fill up the less pressure and will move considerably straighter around the air masses. The heights at which these winds are strongest appear to form jet streams.u can see that these winds will be strongest where air mass temperature differ very much along the atmospheric height. Jet stream coz the jets can take advantage of these high speed winds if they follow the particular altitude.
now deriving some answers from this:
u asked why the polar jet streams are strongest-- we can see that air masses difference here will be highest. For example, between the polar one and temperate one,,,,much more than equator and subtropical…
then u asked why they are flowing in certain directions --- this u shall be able to see with coriolis force as u do for normal winds on the ground,,,the upper winds are similarly affected by coriolis,,,
thanx for ur answer using the basics
I agree on the basic and strength part but some concerns on the direction of JS
Regarding the directions of Jet Streams it isn't so straightforward answer
consider the following facts as well
Polar Jet Streams and Subtropical Jet streams are Westerly flowing Jetstreams whereas Equatorial Jetstream is easterly flowing
Coriollis force can very well explain direction of Polar JS and Subtropical JS
however the big question remains
Why Equatorial Jetstream is East flowing ?
http://weatherfaqs.org.uk/book/export/html/8
Equatorial Easterly Jet
This jet occurs in the northern summer between 10 and 20 deg N, chiefly over or just to the south of high land masses such as in Asia and Africa. Its occurrence is due to a temperature gradient with colder air to the south which produces sufficient temperature differential above 50 000 ft/15 km to give wind speeds of over 100 kt (50 m/s). Because colder temperatures at height are to the south, it is an easterly jet. (This jet is now more usually known as the Tropical Easterly Jet(TEJ) ... perhaps more correctly as it lies some distance from the Equator.)
c what they are saying is that colder temperatures are to the south,,,,perhaps this is happening due to movement of belts with respect to movement of sun,,as the hottest wll be north of equator during northern summers,,,so equator will be realtively colder,,,and coriolis shall take it to right and so when i go right from equator towards subtropical then the jet will go towards the east,,,,
@upsc_cracker
Ans: Due to interaction of cold polar easterlies and warm westerlies at surface. Air mass above cold easterlies which originated from Poles are cold, dense and heavy compare to air mass above warm easterlies brought by westerlies which is warm and rarefied. So, in upper atmosphere pressure above warm westerlies decrease slowly while pressure above cold polar easterlies decrease very rapidly. Due to this at the top intense pressure gradient will develop and very strong moving winds will flow in upper atmosphere. due to corollis force very fast moving wind will move right in northern hemisphere and left in souther hemisphere which is known as polar front jet stream. Hence direction is west to east in both the hemisphere (Ans to part of Q2 also)
@upsc_cracker where have you seen equatorial jet stream, it should be tropical easterly jet stream. kindly confirm and then I will tell why it is moving from east to west.