On the latitudinal variation in OI 630.0 nm dayglow emissions in response to the equatorial electrodynamic processes and neutral winds

Characterization of Gravity Waves in Three Dimensions in the Daytime Thermosphere Using Combined Optical and Radio Measurements and Estimation of Horizontal Neutral Winds

“…Out of these two, the model‐derived winds have a higher uncertainty in their values compared to the neutral atmospheric parameters. In a recent study, it has been shown that the optical dayglow emissions are influenced by the meridional (poleward) winds as they transport the constituents spatially (Kumar et al., 2022). Thus, this comparison serves as a motivation to explore the possibility of obtaining values of thermospheric neutral winds using the measured characteristics of gravity waves, information on which is very limited in the daytime.…”

“…However, these measured winds cannot be readily used for comparison, as MIGHTI winds are not available for all times at a given location. Therefore, to obtain the diurnal variation of these measured neutral winds over our observational location, Ahmedabad, we have used a methodology described in one of our earlier works (Kumar et al., 2022). In this method, we use the HWM14 (Drob et al., 2015) model‐derived winds to describe the climatological variations between the latitude of interest and the latitude of MIGHTI observations in a longitude region at a given time.…”

“…As mentioned above, the difference between the HWM14 and MIGHTI measured winds at that location is added to the HWM14 winds over Ahmedabad at a given time and thereby we obtain the diurnal variation in winds over Ahmedabad. This ‘MIGHTI added HWM14 winds’ method was successfully applied in the earlier study (Kumar et al., 2022) to obtain neutral winds over Ahmedabad, and interesting dynamics of meridional winds versus OI 630.0 nm dayglow emissions intensity variation were obtained. While this method provides neutral winds over Ahmedabad, for it to be compared with the estimated winds in the present study, measured winds along the direction of wave propagation are required to be considered.…”

“…The wind measurements from MIGHTI cover the spatial region of 12°S to 42°N geographic latitudes. Further, we have used MIGHTI added HWM14 winds, an approach described in Kumar et al (2022) to estimate the diurnal variation in thermospheric winds at a given location. In this approach the MIGHTI winds are used to provide day-to-day corrections to those provided by the HWM14, which is climatological in nature, thereby yielding the diurnal variation of thermospheric wind at a given location, as briefly described in Section 4.4 below.…”

Response of ICON/MIGHTI Measured Low‐Mid Latitude OI630.0 and OI557.7 nm Dayglow Emissions to the 27 August 2021 Geomagnetic Storm

“…As previously mentioned regarding the role of the equatorward wind, the equatorward wind observed during the studied geomagnetic storm can induce changes in neutral compositions and plasma within the mid‐low latitude region. These changes encompass heightened molecule densities, an elevated ionosphere (Karan et al., 2016; Karan & Pallamraju, 2020; Rishbeth, 1977; Titheridge, 1995), and thereby affect the airglow emission intensities (Kumar et al., 2022; Saha et al., 2021). According to the simulation by Culot et al.…”