The tropopause varies and depends on the temperature at ground level. As the temperature decreases as you go up, the height at which it stops decreasing is where the Tropopause occurs. It is significant for pilots as that is where you experience the jetstreams and is also an upper limit for cloud tops. A low tropopause can be around 280 (28,000 ft) and a high one around 520 (52,000 ft). If it is in a box it is average. If it has pointed top looking like a house, it is high. If the point is on the lower side it is a low tropopause. In case I have over simplified this, here is a more in depth article on the subject.
The height of the tropopause