Investigation of Large Scale Traveling Atmospheric/Ionospheric
Disturbances using the Coupled SAMI3 and GITM Models
Abstract
We present simulation results of the vertical structure of Large Scale
Traveling Ionospheric Disturbances (LSTIDs) during synthetic geomagnetic
storms. These data are produced using a one-way coupled SAMI3/GITM
model, where GITM (Global Ionosphere Thermosphere Model) provides
thermospheric information to SAMI3 (SAMI3 is Another Model of the
Ionosphere), allowing the production and propagation of LSTIDs. We show
simulation results which demonstrate that the traveling atmospheric
disturbances (TADs) generated in GITM propagate to the topside
ionosphere in SAMI3 as LSTIDs. The speed and wavelength (900 m/s and
10º-20º latitude) are consistent with LSTID observations in storms of
similar magnitudes. We demonstrate the LSTIDs reach altitudes beyond the
topside ionosphere with amplitudes of <5% over background
which will facilitate the use of plasma measurements from the topside
ionosphere to supplement measurements from GNSS in the study of TIDs.
Additionally, we demonstrate the dependence of the characteristics of
these TADs and TIDs on longitude.