Wind never stops

[Smotsholle]

Hello, maybe a strange question, but at the moment it's storming over here.

 

I've learned in school that wind is caused by pressure differences in different areas. Pretty much like letting the air out of the balloon (high pressure) and into the open (low pressure).

It's logical why letting the air out of the balloon creates something like a gust of wind, but this is because there is a relatively small opening in the balloon through which a lot of air escapes.

 

I can't wrap my head around this principle working on a global scale.

Unlike the balloon the air on top of the earth has no small gaps or openings, so the cause of storms and hurricanes must be a huge air pressure difference.

 

However, if the air moves from a high pressure area to a low pressure area, one would expect that eventually both areas whould have the same air pressure.

 

On a global scale where air moves freely, I would expect the air pressure would be spread out in due time.

 

 

 

My question, what on earth raises or lowers air pressure in certain spots so much that it can create storms?

In the balloon example the pressure is contained within the balloon until someone lets it out. In the outdoor air this principle doesn't apply.

 

I'm no scientist and I'm probably missing something obvious here, but I'd like to know what.

 

Thanks in advance.

[Ophiolite]

Put very simply it is variations in thermal input from the sun. Some areas heat up, the air expands, becomes less dense and pressure falls. Other areas cool and the reverse occurs. since there is always an imbalance of thermal input based on latitude and complicated by day/night and cloud cover etc then there is no way in which a balance can be attained.

[StringJunky]

Hello, maybe a strange question, but at the moment it's storming over here.

 

I've learned in school that wind is caused by pressure differences in different areas. Pretty much like letting the air out of the balloon (high pressure) and into the open (low pressure).

It's logical why letting the air out of the balloon creates something like a gust of wind, but this is because there is a relatively small opening in the balloon through which a lot of air escapes.

 

I can't wrap my head around this principle working on a global scale.

Unlike the balloon the air on top of the earth has no small gaps or openings, so the cause of storms and hurricanes must be a huge air pressure difference.

 

However, if the air moves from a high pressure area to a low pressure area, one would expect that eventually both areas whould have the same air pressure.

 

On a global scale where air moves freely, I would expect the air pressure would be spread out in due time.

 

 

 

My question, what on earth raises or lowers air pressure in certain spots so much that it can create storms?

In the balloon example the pressure is contained within the balloon until someone lets it out. In the outdoor air this principle doesn't apply.

 

I'm no scientist and I'm probably missing something obvious here, but I'd like to know what.

 

Thanks in advance.

 

On a global scale, you are forgetting the Earth is orbiting and rotating around the Sun...as one area heats up facing the Sun, another area in darkness is cooling down...this effect maintains the disequilibrium and keeps the wind going.

Edited January 6, 2012 by StringJunky

[Smotsholle]

Thanks for your answer.

 

Never thought the change of temperature could have that big an impact. Now I know

[Ophiolite]

Indeed. It is the temperature difference that powers the winds. We see it at every scale. For example, the strength of hurricanes and typhoons is proportional to the sea temperature they pass over. The hotter the water the stronger the winds. (It's more complex than that, but I'm already pushing my limits on the topic.) I don't know if you live by the sea, but on days where there is little 'regional' wind one will often get a breeze coming from the cold air over the sea to replace the rising warmer air over the land. At night the wind direction may reverse as the land cools much faster than the sea.

[Leader Bee]

While temperature is one of the main factors in creating wind you'll also find that humidity is a factor too. Storms can last a long time over the ocean and you may have noticed on the news tropical storms being reported for some weeks before they arrive in cities but they only last at most a couple of days once they're over land so topology is also a contributing factor to weather.

 

Mountains that are high enough are like their own little islands of weather systems too. Wind from regular pressure systems can be forced to rise up their steep sides creating stong winds, clouds, rain and snowstorms.

[Ophiolite]

While temperature is one of the main factors in creating wind you'll also find that humidity is a factor too. Storms can last a long time over the ocean and you may have noticed on the news tropical storms being reported for some weeks before they arrive in cities but they only last at most a couple of days once they're over land so topology is also a contributing factor to weather.

I could very well be wrong, but I think this is also a temperature effect transmitted via the humidity. Thermal energy is transferred to the air mass via evaporation of ocean water, thereby maintaining or increasing the sotrms energy. Once over land, apart form frictional effects reducing velocity, this source of energy replenishment is no longer available. I stand ready to be corrected on this one, but that is certainly my decades old recollection.

[Leader Bee]

No, you are correct and this confusion has been down to my poorly worded explanation of the process.

[michel123456]

Thanks for your answer.

 

Never thought the change of temperature could have that big an impact. Now I know

Why are you accepting such explanations so quickly?

Since the rotational rate of the Earth is stable, why is weather so capricious? Wouldn't weather have become standard all around the globe, based only on variations caused by physical phenomena like the Coriolis force?

[Leader Bee]

Why are you accepting such explanations so quickly?

Since the rotational rate of the Earth is stable, why is weather so capricious? Wouldn't weather have become standard all around the globe, based only on variations caused by physical phenomena like the Coriolis force?

 

As seen in Jupiters distinct cloud bands?

[Ophiolite]

Why are you accepting such explanations so quickly?

Since the rotational rate of the Earth is stable, why is weather so capricious? Wouldn't weather have become standard all around the globe, based only on variations caused by physical phenomena like the Coriolis force?

I take it you doubt the explanations. You don't think there are variations in thermal input as a consequence of diurnal and seasonal variations, plus variations in cloud cover, atmospheric humidity, aerosol content, dust content, etc,? All of these cause the temperature of the ground and hence of the air to vary from location to location and within a given location. You don't believe these variations can account for the weather? What evidence do you have that they do not produce these effect?

[StringJunky]

Why are you accepting such explanations so quickly?

Since the rotational rate of the Earth is stable, why is weather so capricious? Wouldn't weather have become standard all around the globe, based only on variations caused by physical phenomena like the Coriolis force?

 

The OP never asked why the weather was so capricious only why the wind never stopped and what Ophiolite and I have said more than suffices.

[swansont]

Why are you accepting such explanations so quickly?

Since the rotational rate of the Earth is stable, why is weather so capricious? Wouldn't weather have become standard all around the globe, based only on variations caused by physical phenomena like the Coriolis force?

 

The rotation rate is fairly stable but the length of a day is less so; variations in the orbit also lead to a variation in the amount of sunlight we get. There is also an inclination which causes variation in the amount of sunlight, and there is a solid surface which is not smooth. The solar output is also not a constant.

[michel123456]

As seen in Jupiters distinct cloud bands?

Yes.

 

--------------------

Weather works like a chaotic system.

If the solar system is not chaotic, including planet Earth, why is the weather chaotic?

Edited January 6, 2012 by michel123456

[Ophiolite]

As seen in Jupiters distinct cloud bands?

 

Yes.

 

--------------------

Weather works like a chaotic system.

If the solar system is not chaotic' date=' including planet Earth, why is the weather chaotic?

[/quote']

You seem to be unaware that Jupiter's cloud system is decidedly chaotic and stormy and the winds just keep on blowing.

[michel123456]

I take it you doubt the explanations. You don't think there are variations in thermal input as a consequence of diurnal and seasonal variations, plus variations in cloud cover, atmospheric humidity, aerosol content, dust content, etc,? All of these cause the temperature of the ground and hence of the air to vary from location to location and within a given location. You don't believe these variations can account for the weather? What evidence do you have that they do not produce these effect?

 

I think if you model all of this after a few years you should obtain a regular smooth weather.

 

You seem to be unaware that Jupiter's cloud system is decidedly chaotic and stormy and the winds just keep on blowing.

 

There is a difference between weather on Jupiter and weather on Earth.

http://www.universetoday.com/wp-content/uploads/2008/06/jupiterweather.gif

Edited January 6, 2012 by michel123456

[StringJunky]

Yes.

 

--------------------

Weather works like a chaotic system.

If the solar system is not chaotic, including planet Earth, why is the weather chaotic?

 

Uneven surface topology , unevenly distributed and variable masses of water, massive forests like the Amazon, localised humidity, transient and localised heat pockets, transient and localised cold pockets, changing icecaps, ozone holes, volcanic activity and most likely many more contribute to a highly variable system.

[michel123456]

Uneven surface topology , unevenly distributed and variable masses of water, massive forests like the Amazon, localised humidity, transient and localised heat pockets, transient and localised cold pockets, changing icecaps, ozone holes, volcanic activity and most likely many more contribute to a highly variable system.

 

Half of these explanations can be resumed as : life

[Ophiolite]

I think if you model all of this after a few years you should obtain a regular smooth weather.

Think it as much as you like - you would be wrong. Cite me a single climate or weather model that results in smooth weather. Opinions count for very little in science. That's all your pushing here.

 

There is a difference between weather on Jupiter and weather on Earth.

http://www.universetoday.com/wp-content/uploads/2008/06/jupiterweather.gif

Of course there are differences. There are also similarities. But that is not the point. The point is that on Jupiter the weather is hugely variable. You appeared not to realise this. Why is it variable? Because of variable thermal input to a naturally chaotic system. I am at a loss to why you favour personal feelings over objective evidence. It puts you in a bad light.

[michel123456]

Think it as much as you like - you would be wrong. Cite me a single climate or weather model that results in smooth weather. Opinions count for very little in science. That's all your pushing here.

 

 

Of course there are differences. There are also similarities. But that is not the point. The point is that on Jupiter the weather is hugely variable. You appeared not to realise this. Why is it variable? Because of variable thermal input to a naturally chaotic system. I am at a loss to why you favour personal feelings over objective evidence. It puts you in a bad light.

 

Climate weather models have a goal: look as much as possible like real weather.

And yes, I will think as much as I like.

And it will go bad, you are right, so I'll stop here.

[swansont]

Half of these explanations can be resumed as : life

 

Even if that's correct, so what? The answer that we should expect a chaotic system remains the same.

[Smotsholle]

The reason I accepted the answer so quickly was because I've heard people I know speak of it.

 

Though I know it to be true, It's hard to wrap my head around it.

Like water seeking out the lowest point, a balance is eventually created. The way I think I would expect the same with the wind in the long run, I understand why I'm wrong.

 

 

The sea example sounds familiar. I live close enough to the sea to know the wind never stops there (northwestern part of the Netherlands).