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horizontal wind shear above a strong surface inversion
StBrendan created the topic: horizontal wind shear above a strong surface inversion
First question on this forum. Working through the X country endorsement text. On page 31 Exercise GM 3, Question 5:
Strong horizontal wind shear can be encountered:
..answer is given as [a] above a strong surface inversion.
Re-reading back over the preceding text, this seems to contradict everything the text says. eg on the very preceding page, page 30, it says "Flying conditions below the inversion will be hazy, with persistent light to moderate turbulence, while above the inversion there will be a dramatic change to good visibility and smooth air. This subsidence inversion contributes strongly to the clear and fine conditions characteristic of so many highs" At the start of the inversion discussion it says " a temperature inversion is an indication of a very stable atmosphere"
I thought I understood the text perfectly until I got to this question. Now I'm totally confused. Can anyone please help reconcile what the text is saying, and the answer to this question?
bobtait replied the topic: horizontal wind shear above a strong surface inversion
The Question answer actually says (a) above a strong SURFACE inversion. The text you quoted was describing a SUBSIDENCE inversion. A surface inversion occurs when cold surface air remains almost stationary, while the air above it is moving rapidly. Thaat's quite different to subsidence inversion on a high pressure sysem which is typically 6000 yo 8000 ft high.