4

The lowest atmospheric pressure in a tropical cyclone is generally located in the eye at the center of the cyclone; however, the air in the eye is descending, while the air in the surrounding portions of the cyclone is strongly ascending:

enter image description here

(Image by Kelvinsong at Wikimedia Commons.)

How, then, is the pressure in the eye, where the air is sinking, lower than that in the eyewall, where the air is rising?

3TW3
  • 413
  • 1
  • 3
  • 14
Vikki
  • 317
  • 1
  • 3
  • 13
  • What's the rationale that leads you to think that there is some sort of incompatibility between low pressure sinking air? – Camilo Rada Aug 15 '18 at 23:32
  • 1
    @CamiloRada: Because, in meteorology, low atmospheric pressure is essentially always caused by air rising, and high pressure by air sinking. – Vikki Aug 15 '18 at 23:34
  • My background is in physics, not meteorology. But I think you might have a misleading association of causality. Rising air is associated with low pressure in density driven flows. As one of the biggest controls of density is temperature, warmer air is less dense, therefore it rises creating a column of air less dense than the surroundings. As a consequence the pressure under that column is lower. For a cyclone the picture seem to be much more complex, so I'll wait until one of the meteorologist around give an answer. Anyway, in the picture looks like the eye have both rising and sinking air. – Camilo Rada Aug 16 '18 at 00:45
  • @Sean - duplicate - https://earthscience.stackexchange.com/questions/13554/why-does-hot-air-sink-in-the-eye-of-a-tropical-cyclone ? –  Aug 16 '18 at 01:45
  • @gansub: That question is about why the air in the eye sinks in the first place; my question is about why the barometric pressure in the eye is the lowest in the cyclone despite that sinking air. – Vikki Aug 16 '18 at 02:00
  • @Sean point taken –  Aug 16 '18 at 02:10
  • @CamiloRada - Not quite. The pink swirling lines is the cyclonic circulation(anti clockwise) It is not rising air. It is the blue lines that refer to the sinking air. –  Aug 16 '18 at 08:24
  • not despite, because of, the air is sinking because it is flowing toward lower pressure. Low pressure would obvious pull down cool air easier than warm air. the sinking is not creating low pressure it is caused by it. – John Aug 18 '18 at 19:09
  • @Sean heard of http://glossary.ametsoc.org/wiki/Indirect_circulation –  Feb 10 '19 at 13:16

0 Answers0