[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-25] The effects of lower atmospheric forcing and geomagnetic activity on the day-to-day variability
of the F2 region ionosphere electron densities

★Invited Papers

*Wenbin Wang¹, Dong Lin¹, Haonan Wu¹, Jia Yue², Jack Wang², Xuguang Cai³ (1.National Center for Atmospheric Research, 2.NASA GSFC, 3.CU Boulder)

Keywords:Ionosphere, Waves, lower atmosphere-ionosphere couling, Modeling

The Earth’s F2-region ionosphere is greatly influenced by transport processes, including those by
neutral winds and electric fields. In this study, we employ the Thermosphere Ionosphere
Electrodynamics General Circulation Model (TIEGCM) to investigate the separate and combined
effects of lower atmospheric wave forcing and geomagnetic activity on F2-region ionospheric
plasma transport and electron density variability. The lower boundary of the TIEGCM is nudged
with the outputs from the Special Dynamics-Whole Atmosphere Community Climate Model
with thermosphere and ionosphere extension (SD-WACCM-X). SD-WACCM-X provides a more
realistic specification of lower atmospheric tides and planetary wavs that affect thermospheric
winds and dynamo and thereby ionospheric electron densities. We compare TIEGCM
simulations with and without SD-WACCM-X nudging and observations to assess upward
propagating lower atmospheric waves effects and the pathways by which these effects occur.
High latitude forcing is also turned on and off in these simulations for geomagnetically quiet,
moderate and storm conditions to evaluate how the lower atmospheric waves precondition and
interaction with high latitude forcing effects, and their relative roles in ionospheric day-to-day
variability.