2 eternal questions about pressure

[arkestra]

Hi people!

1. I've read many times here in some frantic moments that "we are at the limitis of physics", with Monica, Wilma, etc... But what is the minimal pressure possible for each basin, if environment is at its best for development? (and why can we say that physics cannot go below this pressure)

2. There are significant differences between Pacific, Atlantic and Southern Hemisphere pressures. Does this mean that storms are more powerful in the Pacific, or pressure is relative and power of storms are somehow comparable (Wilma's 882mb would be equal in intensity to Tip's 870mb)?

Thank you for the time you may spend answering those two questions, I'm very grateful!

[Aslkahuna]

Yes, there is a limit as to how low the pressure can go at sealevel under typical atmospheric conditions and other factors. On a different planet the limits would be different of course. The lowest possible estimated pressure for a storm in WPAC would appear to be around 858 mb. However, since we have no in situ measurements of storms except in the ATL basin it's only conjecture as to how low the pressure can actually go. As far as the different pressures for given intensities, it's all related to the fact that the ambient pressure surrounding the storm is different. WPAC will have more strong storms than the ATL for a number of reasons-first the long overwater trajectories will favor strong storms and secondly, there are more storms out there. Also, the upper air environment is generally more favorable for intensification. The Atlantic has the advantage of having recon so we know that the relationship between pressure and intensity is not that straightforward-there are other factors as well. Wilma's 882 mb (6th lowest sealevel pressure worldwide) on the face of it would be equivalent to Tip but the winds were not as strong as those with Tip.

Steve

[arkestra]

Thank you Steve, that was very instructive and clearly explained (as it was for Monica).