An inversion is a naturally occurring phenomena when the temperature goes from normal (warmer near the Earth's surface and cooling upwards) to inverted (colder near the Earth's surface and warming upwards). This frequently happens in areas where a warm front is able to ride on top of a cold front. When the colder air is trapped in place for some reason, this condition can persist for a lengthy amount of time. In Salt Lake City, where I live, this condition occurs because Salt Lake is in a "bowl" surrounded by mountains. The cold air if frequently trapped in the valley when there are no storms to move it out. This causes the inversion, which wouldn't be a problem, except all of the pollution from cars and factories are contained in the valley as well, making the air often very unhealthy to breathe. The picture below is a view of today's inversion. There are mountains and a city usually in that shot.
Salt Lake City on a nice day of inversion.
A nice beer to calm all paranoia about what the inversion is doing to my lungs.
A nice picture showing what an inversion looks like from above is pictured on the box.
I have been waiting for a "nice" inversion day to post this Drunk on Geology post. The worst days often occur during December and January, however this winter had been a rather mild inversion year.
I just wish they had included some words on what the meaning of an inversion was on the box or the bottles.