Friday, January 29, 2010

Atmospheric Inversion: Utah's Winter Woe

What is an atmospheric inversion? And why every winter is it the talk of the town (city) in Salt Lake?

Meteorologically speaking, an inversion is a deviation from the normal change of an atmospheric property with altitude. Big deal right? Here's why...

When a warm air mass moves over another cold, dense, air mass -- as it often does during winter in northern Utah's Salt Lake Valley, that colder air mass settles into the land-locked valley, becomes heavy; and because of its weight and lack of wind movement at lower elevations, it cannot move. The end result is a visibly stagnant air mass in the form of low clouds, fog and/or haze.

So again, why is this a big deal? An inversion can lead to extremely dangerous pollution such as smog being trapped close to the ground, with possible adverse effects on health. This is why, believe it or not, Utah, has some of the worst air quality in the United States.

How does an inversion disappear? Typically an inversion only occurs when high pressure is dominating the troposphere (the lower region of the earth's atmosphere). During high pressure air sinks and becomes trapped. But when a low pressure system is overhead air rises, therefore lifting the inversion from the valley and disintegrating its associated pollutants from the earth's surface.

So what's the catch? If you like fair, sunny weather, deal with the inversion. If you don't want to deal with the inversion, you'll have to deal with it being stormy.

For those followers who needed a better understanding of what the inversion was, I hope The Northeast Quadrant was able to help!