Tropospheric Folding

[Ed Lizard]

I was lurking in the global warming argument forum, and got to thinking about the troposhere.

Google searches on folding seem mainly about transport of ozone and the such between the troposphere and the stratosphere, but I'm thinking of soundings/forecast soundings I looked at with high wind events in Winter storms.

Any ruminations, thoughts, about this, feel free.

[Amped]

I was lurking in the global warming argument forum, and got to thinking about the troposhere.

Google searches on folding seem mainly about transport of ozone and the such between the troposphere and the stratosphere, but I'm thinking of soundings/forecast soundings I looked at with high wind events in Winter storms.

Any ruminations, thoughts, about this, feel free.

If you want an answer, ask an actual question. It is impossible to extract one from your post.

[Ed Lizard]

If you want an answer, ask an actual question. It is impossible to extract one from your post.

I don't exactly know what my question is, actually. Just hoping for people who actually know to discuss it.

[Amped]

I don't exactly know what my question is, actually. Just hoping for people who actually know to discuss it.

Look Isentropes are crossing the tropopause. Couldn't have googled that yourself.

[AtticaFanatica]

He wants some actual soundings showing it, what's the big deal?

[Amped]

He wants some actual soundings showing it, what's the big deal?

I gave him a model cross section, cause I assumed a single point sounding wouldn't show him much.

[turtlehurricane]

I was lurking in the global warming argument forum, and got to thinking about the troposhere.

Google searches on folding seem mainly about transport of ozone and the such between the troposphere and the stratosphere, but I'm thinking of soundings/forecast soundings I looked at with high wind events in Winter storms.

Any ruminations, thoughts, about this, feel free.

It is actually one of the most important mechanisms in the development of mid-latitude cyclones. I suggest googling and AMS searching it.

[usedtobe]

There are plenty of articles and presentations on tropospheric folding and cyclone development. Most major snowstorms are associated with tropospheric folds.

Here are two examples,

The latter was from a presentation by Skye Martin.

[wi_fl_wx]

It is actually one of the most important mechanisms in the development of mid-latitude cyclones. I suggest googling and AMS searching it.

Aaaah yes of course the Wisconsin people will chime in on the importance of upper-level fronts and tropopause folding. I assume you heard plenty of that from Dr. Martin in AOS 452? It's all very intriguing and not really in the mainstream despite how frequently tropospheric folds occur--and how much high-ozone, stratospheric air is mixed down into the troposphere.

[turtlehurricane]

Aaaah yes of course the Wisconsin people will chime in on the importance of upper-level fronts and tropopause folding. I assume you heard plenty of that from Dr. Martin in AOS 452? It's all very intriguing and not really in the mainstream despite how frequently tropospheric folds occur--and how much high-ozone, stratospheric air is mixed down into the troposphere.

Yup, that was a great class.

[Amped]

Aaaah yes of course the Wisconsin people will chime in on the importance of upper-level fronts and tropopause folding. I assume you heard plenty of that from Dr. Martin in AOS 452? It's all very intriguing and not really in the mainstream despite how frequently tropospheric folds occur--and how much high-ozone, stratospheric air is mixed down into the troposphere.

Those upper level fronts play an equal role in surface cyclones. Notice the Mid Stratosphere is a lot warmer over the surface arctic airmass. When that stratosphere pushed over a warm surface region the Atmospheric column is going to be too warm and light. Not surprisingly, surface lows are often found where the lowest 500mb heights are on top of the warmest 850 temps.

[turtlehurricane]

Those upper level fronts play an equal role in surface cyclones. Notice the Mid Stratosphere is a lot warmer over the surface arctic airmass. When that stratosphere pushed over a warm surface region the Atmospheric column is going to be too warm and light. Not surprisingly, surface lows are often found where the lowest 500mb heights are on top of the warmest 850 temps.

That's not quite how it works. Essentially, tropospheric folds inject high potential vorticity air from the stratosphere into the upper-troposphere, and even the mid-troposphere in strong cases. This acts as a positive PV anomaly in the upper-troposphere, generating a cyclonic circulation to a certain distance, even close to the surface in low static stability (neutrally buoyant) air. It basically generates a field of circulation (like a magnet generates a magnetic field), which can be dampened by high static stability (which prevents parcels from moving).

Another important fact before the punch line is these tropospheric folds/upper-fronts occur along the baroclinic zone. Therefore, the circulation associated with them can pull warm/moist air north, while pushing cold/dry air south. This leads to the development of the surface cyclone as frontogenesis increases at all levels below the fold.

The fact of the matter is, almost all mid-latitude cyclones are generated by this process.