Wind patterns and thermal inversions trap contaminants in the valley.

In some canyons, thermal inversion also allows for a more humid climate.

A succession of unyielding thermal inversions made January especially asphyxiating.

As a result, thermal inversion that traps Tehran's polluted air is frequently observed.

Thermal inversions can occur any time of the year where cool air sinks and gets trapped in the valleys.

The pollution is worst during winter, when thermal inversions trap the warmer polluted air above the city.

However, a much stronger thermal inversion is often required than is needed for ducting in the 2-meter band.

The crisis was caused by the climatic phenomenon of "thermal inversion", which trapped emissions at near-ground level.

The studies found that the plumes rose high enough to penetrate thermal inversions, which trap smog during cold weather under a layer of warmer air.

There is one-third less oxygen for efficient fuel combustion, and cold layers of air in winter trap toxic emissions with thermal inversions.

Robert Topper The meteorology texts I consulted list two main types of thermal inversion.

In summer, however, the top of Mount Tamalpais may actually be warmer than the middle, foggy elevations due to a thermal inversion.

A Fata Morgana requires a duct to be present; thermal inversion alone is not enough to produce this kind of mirage.

In addition, during the flight an unusual weather phenomenon of thermal inversion occurred, with temperature rising with altitude, which the pilot could not have predicted.

But if winds die down or turn, Paris, like other European cities, has thermal inversions on winter days and a soupy smog in mid-summer.

It may also be the case that Kepler-6b has a thermal inversion of its atmosphere, where temperature increases with increasing distance from the center of the planet.

Due to frequent thermal inversions during the summer, it is often warmer on Mount Hamilton than in San Jose.

This year there were thermal inversions every day in January, 27 days in February and 28 days in March.

Like Mexico City, Santiago lies among mountains and is subject to thermal inversions that do not permit polluted air to escape during the winter months.

Pollution is worst during winter months, when cold air over the city produces a "thermal inversion" effect, trapping the warmer, polluted air close to the surface.

The topography of the area is not conducive to easy dispersion of airborne pollution, due to the phenomenon of thermal inversion.

And even more than Los Angeles, Mexico City is ringed by mountains that trap the smog during regular thermal inversions.

But if the western breezes die down or turn, car fumes are trapped in thermal inversions in winter or make for a soupy summer smog.

"The thermal inversion gradient of the armaglass portal is not precisely known," Doc Tanner replied, taking his usual spot on the floor.

Proponents of the scheme believe the fans would form artificial tornadoes of polluted air, which would be propelled up through the thermal inversion "cap".