The wealth of observational data from multiple spacecraft currently in operation at different locations around the inner heliosphere can set constraints to the morphology and topology of various solar and heliospheric structures, such as coronal holes, active regions, prominence eruptions, streamers, Extreme Ultra Violet waves, co-rotating interaction regions and coronal mass ejections (CMEs) to name a few. Furthermore, such observations can provide valuable information regarding the propagation behavior of transient structures. This behavior is governed to a high degree by the ambient magnetic field and plasma flow in which these structures are embedded, which has important effects on the geo and planetary-effectiveness of, for example, CMEs. As such, the preconditioning of interplanetary space has immediate consequences for predicting the arrival times and impact speeds of CMEs and is, therefore, an important parameter for (Planetary) Space Weather forecasting.

This session focuses on studies covering observations at multiple vantage points, remote and in-situ, as well as theories and simulations from which the structuring of interplanetary space may be identified and how this may affect disturbances evolving in the inner heliosphere.

This joint session invites papers that are related to the mesosphere and lower thermosphere. It addresses the topical fields of the VarSITI (Variability of the Sun and Its Terrestrial Impact) program initiated by SCOSTEP, focusing on the role of the sun and the middle atmosphere/thermosphere/ionosphere in climate (ROSMIC). Contributions studying radiation, chemistry, energy balance, atmospheric tides, planetary waves, gravity waves, neutral-ion coupling, and the interaction of the various processes involved are welcome. This includes work on model data as well as measurements from satellites and ground based platforms such as ALOMAR.