12-Year Study Shows Close Link Between Temperature, Ozone Loss

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A cooperative study involving NASA scientists quantifies, for the first time, the relationship between Arctic ozone loss and changes in the temperature of Earth's stratosphere.

The results indicate the loss of Arctic ozone due to the presence of industrial chlorine and bromine in Earth's atmosphere may well be sensitive to subtle changes in stratospheric climate. Such ozone depletion leads to increased exposure to harmful, ultraviolet solar radiation at Earth's surface.

According to the study, the sensitivity of Arctic ozone to temperature is three times greater than predicted by atmospheric chemistry models. This leads to the possibility that decreases in stratospheric temperatures may have significantly larger impacts on future Arctic ozone concentrations than have been expected in the past. Dr. Markus Rex of the Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany, led the study. It also included scientists from NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The researchers analyzed more than 2,000 balloon measurements collected over the past 12 years. They found the amount of ozone loss occurring in any given Arctic winter is closely related to the amount of air exposed to temperatures low enough to support the formation of polar stratospheric clouds. Reactions occurring on the surface of these clouds convert chlorine from unreactive forms to other forms that quickly deplete ozone. Based on the relation between ozone loss and polar stratospheric cloud existence, the researchers found every degree Kelvin (equal to one Celsius degree) cooling of the Arctic results in an additional ozone destruction of five percent. This sensitivity is a factor of three larger than previously predicted by state-of-the-art, coupled climate- chemistry computer models."

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