Aura Is Designed To Answer Questions About Changes In Our Life-Sustaining Atmosphere

Aura's four instruments study the atmosphere's chemistry and dynamics. Aura's measurements will enable us to investigate questions about ozone trends, air quality changes and their linkage to climate change.

Aura's instruments will observe important sources, radicals and reservoir gases. Therefore the data Aura will supply will help improve our capability to predict ozone changes.

Now in orbit, Aura has joined the "A-Train," a formation of Earth-observing satellites that fly together in order to get a more comprehensive picture of the planet

The stratospheric ozone layer shields life on Earth from harmful ultraviolet radiation emitted by the sun. Certain chemicals in the stratosphere (~15 - 50 km altitude) can act to deplete ozone (O3), most notably in the polar winter/spring, giving rise to the Antarctic 'ozone hole'. The ozone hole is the result of a series of complex interactions between chemistry, cloud formation, winds, sunlight and temperature.

Chemical depletion of ozone occurs mainly through reactions involving chlorine (Cl). Most of the chlorine in the stratosphere originates from man-made chlorofluorocarbon (CFC) gases released into the atmosphere. CFCs are chemically very stable so, unlike most chemical pollutants, they can survive the several year journey that air takes to travel from the lower atmosphere into the stratosphere. Once in the stratosphere, the CFCs are eventually broken down by the strong sunlight at these altitudes, and the chlorine atoms they contain form the molecule HCl, itself also fairly stable. While HCl is a 'safe' (i.e., non ozone depleting) form of chlorine, HCl molecules are occasionally broken down - by sunlight or reaction with other chemicals - into other forms such as the ozone depleting ClO.