Cooperative Institute for Research in Environmental Sciences

Impact of Atmospheric Tides on Ionosphere-Thermosphere System

T.-W. Fang(1), T. J. Fuller-Rowell(1), R. A. Akmaev(2), and F. Wu(1)

1 CIRES, University of Colorado, Boulder, Colorado, USA 2 Space Weather Prediction Center, NOAA, Boulder, CO, USA

The Coupled Thermosphere Ionosphere Plasmasphere with self-consistent Electrodynamics (CTIPe) model is a nonlinear, coupled thermosphere-ionosphere-plasmasphere code that includes a self-consistent electrodynamics scheme for the computation of neutral wind induced dynamo electric fields. The model consists of a global thermosphere, a high-latitude ionosphere, a mid- and low-latitude ionosphere/plasmasphere and an electrodynamical calculation of the global dynamo electric field. The diurnal and semidiurnal propagating tidal modes are imposed at 80 km altitude with a prescribed amplitude and phase. The Whole Atmosphere Model (WAM) is an extension of the operational weather prediction Global Forecast System (GFS) general circulation model (GCM) to the top of the atmosphere. The model is being built to study and potentially develop a capability to predict the effects of lower atmosphere dynamics and variability on the upper atmosphere and ionosphere. Since atmospheric waves can be important sources in reproducing ionospheric variability and thermospheric phenomena, we implement WAM parameters at the lower boundary of CTIPe. The geopotential height, neutral temperature, zonal and meridional wind which were prescribed by Hough mode at 80 km in CTIPe are replaced by the WAM outputs between 80 and ~100 km. We compare the tidal modes reproduced in CTIPe and WAM thermosphere to validate the wave propagation scheme in CTIPe and to understand their impact on ionospheric electrodynamics. Several thermospheric phenomena such as midnight temperature maximum (MTM) and midnight density maximum (MDM) and influences of planetary waves in ionosphere and thermosphere are also studied using CTIPe with the new boundary condition.