Have a problem with northern Utah's foul air? Blame it on the North Pole, say researchers at Utah State University.
The reason, according to the Utah Climate Center at USU, is the meteorological wallop of the arctic oscillation, a weather pattern. It hasn't been so "negative" since 1950, and that means seesaw highs and lows in pressure that deliver the kind of frigid temperatures and monster snowstorms that have pummeled the central United States and Europe all winter.
Here in the West, the strong negative pattern strengthens the high-pressure ridge that results in pollution-trapping inversions.
As northern Utahns know all too well, when the high pressure sticks around, an upper layer of warm air traps cold air on the valley floors. Pollution builds up in the tight-lidded basins for as long as the ridge prevents Pacific storms from blowing out the ground-level air.
State climatologist Rob Gillies said the pattern is striking. Researchers on his team found it by comparing data from the National Oceanographic and Atmospheric Administration's Climate Prediction Center with data on this season's pollution spikes in Utah.
When the winter begins with a negative arctic oscillation, he said, "then you can look out for those really strong inversions."
But this year the pattern has been unusually strong, with some temperatures 10 to 15 degrees higher than usual in the Arctic and exceptionally cold and snowy patterns in the central and eastern states.
Can the pattern be used to predict bad air in northern Utah? It's too soon to say, according to Gillies. Long-duration inversions are linked to a climate mode that normally repeats itself every 30 days.
"But this isn't good news for weather forecasting," he said, "because such a time scale exceeds the capability of modern weather prediction models."
The inversion-arctic oscillation link seen this year has inspired the climate center to dig even deeper and look for the reliability of the pattern over the past 30 years. And it suggests what lies ahead this season, inversion-wise.
By mid-February, Gillies said, the ridges won't be as intense and cleansing storms from the Pacific can start rolling in.
