I should come up with a list of balloon related resources. However, I like Joe’s list (link in title) at surfingsatellites.org so I can afford to be lazy until I want to add add significantly to his list.
I want to mark this web site. Atmospheric Circulation
I have observed, from balloon flight planning and other projects that the mid-latitude jet stream seems to divide the lower (polar?) tropopause, and the higher mid-latitude tropopause. I think this goes part way to an explanation and expect to return to it to try to understand it.