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Major Scientific Goals and Challenges

When societal and environmental impacts are considered, the dominant scientific and technical goals in upper-atmosphere and near-Earth space can be identified as the following:

• to understand the physical, chemical, and dynamical processes that determine the interactions between the stratosphere, climate, and the biosphere;

• to develop the infrastructure that will permit operational forecasting of "space weather";

• to understand the relationships between changes in the middle and upper atmosphere and the Earth's surface and lower-atmospheric climate; and

• to study solar variability and its influence on the middle and upper atmosphere.

Key Components of the Scientific Strategy

The components of the strategy to address the major scientific issues in upper-atmosphere and near-Earth space science are developed on the basis of four national goals:

1. To study atmospheric processes using observations, laboratory research, theory, and modeling.

2. To have the necessary observations, understanding, modeling capability, and transfer to operations to permit skillful forecasts of "space weather."

3. To document middle- and upper-atmospheric change and produce models that consistently simulate these changes along with those of the lower-atmosphere-surface system.

4. To document changes in solar output, determine how these affect lower-atmosphere and surface climate, and compare these with the climate record.

Scientific Requirements for the Coming Decade(S)

Role of the Stratosphere in Climate, Weather Prediction, and Tropospheric Chemistry

The stratosphere plays two roles in the climate system. The first involves the impact of stratospheric trace gases and aerosols, including those of anthropogenic origin, on radiative fluxes through the tropopause. The second role of the stratosphere in the climate system is through the dynamic coupling between the troposphere and the stratosphere. Considerations of the stratospheric role in various aspects of climate and weather include the following: