To operate below 350km, we must have the density, composition, winds. and temperature profiles in the region - and on a global basis under day, night and auroral conditions.

What are the practical drivers (how much do we know from empirical and first principles models); What are the limitations on our knowledge (e.g the physics of the transition from the mixed to diffusively controlled region); what limits the predictability of a region that sees the transition from strong linkage to lower atmosphere tidal and wave forcing to a region driven by coupling to the magnetosphere, and what measurements and missions can systematically collect global data that provides inputs to assimilative models for global scale nowcasts and the first-principles models that most capture the physics and reproduce the observed behavior. 

We look forward to contributions from users community, empirical, assimilative and first principles modelers, ground- and space-based instrumentation and commercial operators.

• SY - Science and Society
• SH - SPA-Solar and Heliospheric Physics
• SM - SPA-Magnetospheric Physics