Tidal Characteristics of Thermospheric Winds from the MENTAT Wind Model

The new Magnetic mEridional NeuTrAl Thermospheric (MENTAT) wind model uses h_mF₂ observations to model magnetic-meridional neutral winds as a function of solar local time, day of year, year, solar flux, geographic latitude, and geographic longitude. The winds are shown to exhibit the expected hourly, diurnal, seasonal, and solar cycle morphologies in Dandenault, (2018). MENTAT winds also match ground-truth thermospheric wind observations very well. Previous research (Dandenault and Richards, 2015) demonstrates that driving the first-principles field line interhemispheric plasma (FLIP) model using h_mF₂-based winds as the neutral wind input generates strong downward vertical plasma drifts around midnight (the 'midnight collapse' in h_mF₂) in both hemispheres. These simulations also show that it is the terdiurnal tidal component of the winds that is responsible for the sharp decrease in the altitude of h_mF₂. In this paper we will present the results of comparisons of MENTAT wind behavior to the Global Ionosphere-Thermosphere Model (GITM) first-principles general circulation model, and also present additional comparisons to the Horizontal Wind Model. This study will further validate the MENTAT model and provide analyses of the neutral wind characteristics as a function of location, solar local time, season, and solar activity. Visit http://civspace.jhuapl.edu/mentatwinds/ for more information.