By Sid Perkins
New field observations, satellite images, and computer models are steering some scientists toward a surprising conclusion: A severe thunderstorm, enhanced by the heat from a huge forest fire, can boost soot, smoke, and other particles as high as the lower stratosphere. The newly suspected transfer of aerosols to high altitudes could require significant changes in computer models of atmospheric circulation and climate.
Most of Earth’s weather–and most of its air pollution–resides in the troposphere, the layer of atmosphere that extends from the planet’s surface to altitudes between about 8 and 13 kilometers. Previous studies suggested that most particles floating in the stratosphere, the next-highest atmospheric layer, come from volcanic eruptions or are generated on the spot by high-flying aircraft, says Pao K. Wang of the University of Wisconsin–Madison.