[FRIAM] George on Rossby Waves and Frontogenesis

[Nicholas Thompson]

 *Dear Phellow Phriamers,*


*What I love about George is that he speaks what others have in the backs
of heir minds but seem reluctant to say.  So I have been reading in weather
books and articles for weeks, trying to work out the chicken/egg relation
between global-scale and synoptic-scale processes.  None of those sources
has put the relation so plainly as does George below.  Of course he may be
absurdly, flagrantly, ridiculously WRONG, but at least he has put it out
there.  George seems to be good at discovering subtexts.  Think what he
might do for psycho-analysis.*

*Rossby waves, of course, are not only E-W waves along the polar front,
they are also up/down waves along the boundary between the Troposphere and
the Stratosphere, the Tropopause, so that in a Rossby trough, the
Tropopause is much closer to the ground than in a Rossby ridge.   *


*George also believes that Rossby waves often stumble over mountain ranges
and continental boundaries.  When they stumble, they often break, sending
Tropospheric air into the Stratosphere, and bringing Stratospheric air into
the Troposphere, perhaps even as far down as the surface.   You know that
rush of odd-smelling air you get at the onset of a cold front?  That may be
stratospheric air.  *


   1. *Anyway: FWIW, here is George on Rossby Wavess and Frontogenesis.  * *I
   hope to join vFRIAM on Thursday around 11 MDT, in case there are other
   weather nerds on the list who would like to talk about this. *



*Nick*

*What is the relation between Rossby waves and frontogenesis*

*Rossby waves and frontogenesis are closely related atmospheric phenomena,
with Rossby waves playing a significant role in the generation and
maintenance of fronts through the process of frontogenesis. Here's how
they're connected:*

   1.

   *Dynamic Instability: Rossby waves are large-scale meanders in the jet
   stream that develop due to the interaction between the Earth's rotation and
   horizontal temperature gradients in the atmosphere. These waves are
   associated with dynamic instability in the atmosphere, leading to the
   amplification and propagation of disturbances along the jet stream.*
   2.

   *Formation of Temperature Contrasts: Rossby waves often lead to the
   development of regions with strong horizontal temperature gradients, known
   as baroclinic zones, along their troughs and ridges. These temperature
   contrasts are essential for frontogenesis, as they provide the necessary
   conditions for the formation and intensification of fronts.*
   3.

   *Enhanced Vertical Motion: Along the troughs of Rossby waves, there is
   typically enhanced upward motion of air, while along the ridges, there is
   enhanced downward motion. This vertical motion is associated with the
   convergence and divergence of air masses, respectively, which can
   contribute to the formation of fronts through the process of frontogenesis.*
   4.

   *Interaction with Baroclinic Zones: Rossby waves interact with existing
   baroclinic zones in the atmosphere, which are regions of strong horizontal
   temperature gradients. These interactions can lead to the amplification or
   deformation of existing fronts and the generation of new fronts through
   frontogenesis.*
   5.

   *Development of Cyclogenesis: Rossby waves can also contribute to the
   development of cyclones, particularly in regions where there are strong
   temperature gradients associated with fronts. Cyclogenesis often occurs
   along frontal boundaries, where the convergence of air masses and enhanced
   vertical motion associated with Rossby waves create favorable conditions
   for low-pressure systems to develop.*

*Overall, Rossby waves influence the development and maintenance of fronts
through the generation of temperature contrasts, enhanced vertical motion,
and interactions with existing baroclinic zones. Frontogenesis, in turn,
contributes to the intensification and evolution of cyclones and other
weather systems associated with the mid-latitude atmosphere.*
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