Abstract

One common assumption used in many theoretical thermosphere/ionosphere models is hydrostatic equilibrium, under which the pressure gradient force is balanced with the gravity force in the vertical direction. This assumption represents the large-scale atmosphere behavior very well, but on small sp... Show moreOne common assumption used in many theoretical thermosphere/ionosphere models is hydrostatic equilibrium, under which the pressure gradient force is balanced with the gravity force in the vertical direction. This assumption represents the large-scale atmosphere behavior very well, but on small spatial scales and during short time periods, the system can be non-hydrostatic. Non-hydrostatic processes can cause large vertical winds and strong disturbances of neutral density in the upper atmosphere. It is currently unknown what are the global ramifications of the non-hydrostatic processes. Comparison between the non-hydrostatic Global Ionosphere Thermosphere Model (GITM) and the hydrostatic Coupled Thermosphere Ionosphere Plasmasphere model (CTIP) helps us to quantify the non-hydrostatic coupled response of the system to strong driving. Specifically, the investigation begins with turning off all non-hydrostatic terms in GITM and forcing hydrostatic equilibrium at each time-step. The results are compared with a CTIP simulation to show the effects of model differences. The non-hydrostatic terms then are added back in GITM and the results are compared with CTIP again to determine their relative contributions. The simulation results are also compared with ground-based and satellite measurements of the neutral density and winds. Show less