[FRIAM] Potential Vorticity and the Dynamic Tropopause

[Stephen Guerin]

Dan GuPTa had this response when asked to relate your .PDF to Bernard cells
and other prompting:

Here’s a integration of potential vorticity (PV), atmospheric stability,
and their relationship to Bénard cells, emphasizing isentropic layering in
both meteorological and experimental fluid dynamics contexts.

### Connecting Bénard Cells and Atmospheric Dynamics

In Bénard cells, fluid heated from below shows a critical transition from
conductive to convective heat transfer, forming cellular patterns.
Similarly, in the atmosphere, when the vertical temperature gradient
becomes unstable—akin to the Bénard cell transition—convection can
initiate, influenced by factors like the earth's rotation and potential
vorticity.

### Potential Vorticity and Stability

- **PV on Isentropic Surfaces:** Potential vorticity combines fluid
rotation and atmospheric stratification. In meteorology, PV is mapped on
isentropic surfaces (constant potential temperature layers), where it
highlights regions prone to atmospheric instability and potential
convection, akin to early instability in Bénard cells.

- **Dynamic Tropopause:** Acting like the fluid surface in a Bénard cell,
the dynamic tropopause is flexible, responding to distortions from jet
streams. These distortions can lead to convective activity by modifying
local stability and vorticity, driving weather patterns similarly to
temperature gradients in Bénard convection.

### PV Anomalies and Convective Cells

- **Weather Forecasting:** Monitoring PV anomalies helps predict convective
weather events, similar to observing Bénard cells to anticipate pattern
formation. For example, sharp PV changes can indicate regions ripe for
convective storms if conditions like moisture and surface temperature align.

- **Role of Isentropic Layering:** Both in Bénard cells and weather
systems, the spacing between isentropic layers indicates stability. Closer
layers suggest a steep gradient and instability, potentially leading to
convective movements. In the atmosphere, this translates to dynamic
interactions where lower stability near the surface can trigger or enhance
convective processes.

### Conclusion

Understanding the parallels between Bénard cell dynamics and atmospheric
conditions through potential vorticity and isentropic surfaces not only
illustrates universal fluid dynamics principles but also enhances
meteorological predictions of convective weather events, demonstrating how
small-scale changes in stability can lead to significant atmospheric
phenomena.

On Thu, Apr 11, 2024, 2:04 PM Nicholas Thompson <thompnickson2 at gmail.com>
wrote:

>
>
> Hi, Phellow Phriammers,  Nick, here.
>
>
>
>
>
>
> I have been lost in the weather.  This publication,
>
>
>
> https://acrobat.adobe.com/id/urn:aaid:sc:us:d481610b-e5d5-4a03-879c-6db6ec1d5e4a
>
>
> with its glorious eye-candy, is an example of what seems to be a new
> perspective in meteorology, the DT-PV perspective.  PV refers to a
> parameter, potential vorticity, which seems to be a measure of how liable
> the atmosphere is to churn; DT refers to the DYNAMIC tropopause.  The
> tropopause is the transition zone between the stratosphere and our own
> layer, the troposphere, through which gas exchange is limited because the
> lapse rate of the troposphere  -- its decline in temperature with fall of
> pressure -- is reversed in the stratosphere.   In the Bad Old Days, we
> were taught that the tropopause was like a ceiling, tilted upward from the
> poles to the tropics.  Now we have begun to think of it as more like a
> tent fly, still tilted up equator-ward, but loose and floppy and buffeted
> up and down by the jetstreams’ winds. These floppings up and down have the
> power to destabilize the lower atmosphere and lead to bad weather, if
> conditions there are ripe.
>
>
>
> This is not one of my usual cries for help.  I have some good tutors.
> However, I would love to hear from others whom this paper interests.  In
> particular I am struggling with the notion of potential vorticity, whose
> formula seems to take many odd forms.
>
>
>
> Best,
>
>
>
> Nick
>
>
>
>
>
> Nicholas S. Thompson
>
> Emeritus Professor of Psychology and Ethology
>
> Clark University,
>
> nthompson at clarku.edu
>
>
> -. --- - / ...- .- .-.. .. -.. / -- --- .-. ... . / -.-. --- -.. .
> FRIAM Applied Complexity Group listserv
> Fridays 9a-12p Friday St. Johns Cafe   /   Thursdays 9a-12p Zoom
> https://bit.ly/virtualfriam
> to (un)subscribe http://redfish.com/mailman/listinfo/friam_redfish.com
> FRIAM-COMIC http://friam-comic.blogspot.com/
> archives:  5/2017 thru present
> https://redfish.com/pipermail/friam_redfish.com/
>   1/2003 thru 6/2021  http://friam.383.s1.nabble.com/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://redfish.com/pipermail/friam_redfish.com/attachments/20240413/6758b28a/attachment.html>