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These measurements could be accommodated on the dedicated solar monitoring spacecraft identified in Recommendation 1.

11. Monitor globally over long periods the basic structure of thelower thermosphere and upper mesosphere so as to properly define the presentstructure and its response to solar forcing.

12. Conduct observational and modeling studies to understand thechemical, dynamical, radiative and electrical coupling of the upperatmosphere to the middle and lower atmospheres.

Analysis of solar soft X-ray forcing of nitric oxide levels, with possible inferences for nitrate deposits in ice cores, is an example of such a study. Ultimately, a global model of the Earth system is needed.