Statistical Characterization of GITM Thermospheric Horizontal Winds in
Comparison to GOCE Estimations
Abstract
Characterization of the thermospheric horizontal wind is an important
challenge in atmospheric modeling, due to its vital role in the
transport of densities and energy, associations with the diurnal tide,
and interplay with vertical winds that drive changes in the thermosphere
neutral composition. The mechanisms and drivers that underlie the
physics of thermospheric horizontal winds remain under investigation
and, to date, no comprehensive statistical study between thermospheric
winds generated by a physics-based atmospheric model and those retrieved
from satellite measurements has been performed. Comparisons between
cross-track horizontal winds from a 10-month run of GITM and those
derived from the Gravity field and steady-state Ocean Circulation
Explorer (GOCE) satellite showed that GITM’s modeled horizontal winds
best in the polar zone and overestimated them at midlatitudes in the
equatorial ionization anomaly region. GITM’s wind response to AE was
best at polar noon and worst in the midnight auroral zone, its ability
to capture seasonality was best in the northern high latitudes and worst
in the southern high latitudes, and GITM displayed less wind variability
as a function of F10.7 than GOCE, matching it best for
F10.7~150. Discrepancies in GITM’s performance may be
explained by inaccurate modeling of ion drift, ion drag, and electron
densities.