This project will perform a series of investigations to assess the impact of non-hydrostatic processes on the response of the thermosphere/ionosphere system to magnetospheric forcing. Several General Circulation Models (GCMs) will be involved, including the Global Ionosphere-Thermosphere Model (GITM) and the Coupled Thermosphere Ionosphere Plasmasphere model (CTIP) along with data sets from Fabry-Perot interferometers (FPI) and from the CHAMP and GRACE satellites to characterize the non-hydrostatic processes and its impacts on the neutral density variation, and to model these effects in fully coupled global ionosphere-thermosphere circulation models. The specific investigations to be performed are: (1) Examine the magnetospheric energy input uncertainty related to the variability of the electric field, using the Geospace General Circulation Model (GGCM) for the magnetosphere. The relative importance of the electric field variability to the average electric field and its dependence on the level of solar activity, geomagnetic activity, and season will be examined; (2) Compare the non-hydrostatic GITM model with the hydrostatic CTIP model to quantify the significance of non-hydrostatic processes in driving both the neutral and ion distributions; (3) Investigate the dependence of the non-hydrostatic phenomena on the spatial resolution of GCMs and the temporal variation of the energy inputs. Examining the dependence of the non-hydrostatic processes on both the magnitude and the speed of energy inputs in the thermosphere/ionosphere system will elucidate the critical conditions for significant non-hydrostatic phenomena; (4) Use the simulations and the FPI vertical wind observations to confirm the importance of the nonhydrostatic processes on the development of large vertical winds; (5) Compare the simulations with neutral density data from CHAMP and GRACE satellites to understand the large neutral density disturbance in response to the intense electromagnetic energy inputs. The cusp region neutral density enhancement is observed by the CHAMP satellite. The satellite data will be compared with both GITM and CTIP simulations to examine the importance of the non-hydrostatic processes on the neutral density; (6) Examine the impact of non-hydrostatic processes on atmospheric composition and the nitric oxide distribution. Of particular interest is the possible transport of nitric oxide from the upper to the lower atmosphere due to the change of the atmospheric vortices.
