Hello I am unsure where to post general met questions such as this although considering this pertains to tropical cyclones I thought it best to post here. Well anyway, I was wondering if someone (pro met or otherwise) could explain tropical cyclones to me from a PV perspective. I feel I have a pretty good understanding of PV's role in upper level stratosphere/troposphere interactions (tropopause folding), and its role in mid-latitude cyclone development/jet dynamics (and topographic interactions such as lee side troughing, flow reversal etc. stemming from PV conservation).
However, I have trouble understanding PV (anomalies) in tropical cyclones, particularly the creation/destruction of PV by diabatic processes such as latent heat release, and the location in the troposphere of the PV anomaly. Note you may make your response as "mathy" as you like ( I actually hold a degree a meteorology, and am attending graduate school this coming fall, but my undergraduate education (and future graduate studies) was for more focused on micro-physical/radiational processes so my operational mesoscale/synoptic skills are lacking. Thanks in advance, and a moderator can move this to a more appropriate forum if that is required.
PV and Tropical Cyclones?
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PV and Tropical Cyclones?
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Re: PV and Tropical Cyclones?
I look at PV anomalies from the perspective on how it alters the tropopause height.
The basic model in my mind is that a TC is a vortex that basically resides from the surface to the tropopause.
If it is moving into an area of higher PV anomaly, it is moving into a lower tropopause.
That forces the TC vortex to compress vertically and, using conservation of angular momentum, causes the overall vorticity of the TC to spin down. Thereby, overall lower wind speeds.
The classic spinning skater with outstretched arms analogy.
Opposite is true when moving into a very low PV area. Here, the TC vortex can expand vertically causing it to spin up.
I look at the 200mb vorticity from CIMSS to judge PV anomaly.
Anti-cyclone on the shear map confirms a rise in the local tropopause.
The basic model in my mind is that a TC is a vortex that basically resides from the surface to the tropopause.
If it is moving into an area of higher PV anomaly, it is moving into a lower tropopause.
That forces the TC vortex to compress vertically and, using conservation of angular momentum, causes the overall vorticity of the TC to spin down. Thereby, overall lower wind speeds.
The classic spinning skater with outstretched arms analogy.
Opposite is true when moving into a very low PV area. Here, the TC vortex can expand vertically causing it to spin up.
I look at the 200mb vorticity from CIMSS to judge PV anomaly.
Anti-cyclone on the shear map confirms a rise in the local tropopause.
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