Characterization of the Thermospheric Mean Winds and Circulation During Solstice Using ICON/MIGHTI Observations

Using the horizontal neutral wind observations from MIGHTI instrument onboard NASA's ICON (Ionospheric Connection Explorer) spacecraft with continuous coverage, we determine climatology of mean zonal and meridional winds associated circulation at low- to middle latitudes ($10^\circ$S-40$^{\circ}$N) for Northern Hemisphere {summer} solstice conditions between 90 km 200 altitudes, specifically on 20 June 2020 as well a one-month period 8 June-7 July {and winter season 16 December 2019-31 January 2020, which spans 47-day period, providing full local time coverage}. The data are averaged within appropriate altitude, longitude, latitude, solar zenith angle, bins produce distributions. geographical distributions variations evaluated. instantaneous exhibit significant degree spatiotemporal variability often exceeding $\pm 150 $ m s$^{-1}$. daily demonstrate day-to-day variability. Eastward northward (winter-to-summer) prevalent in lower thermosphere, provides indirect observational evidence eastward momentum deposition by small-scale gravity waves. smaller scale structures thermosphere (90-120 km), while they more homogeneous upper indicating increasingly dissipative nature thermosphere. patterns inferred ICON/MIGHTI measurements can be used constrain validate general models, input numerical wave models.