# Thermospheric Neutral Wind Measurements and Investigations across the African Region--A Review
## 2 Highlights on Reports of Thermospheric Neutral Wind Measurements across Africa
By analyzing the storms that occurred during a 3-year period covering 2014-2016, they also established the statistics of the storm-induced circulation in different storm phases. In an earlier total electron content modelling study, [PERSON] et al. (2018) [9] showed that the meridional wind velocity (obtained from the HWM), when included as input, led to improvements in the prediction accuracy of their model in the African region. In the West African equatorial region, [PERSON] et al. (2021) [4] examined the variability of the night-time equatorial thermospheric meridional and zonal wind speeds, using the FPI located in Abuja, Nigeria (Geographic: 8.99\({}^{\circ}\) N, 7.39\({}^{\circ}\) E; Geomagnetic: 1.60\({}^{\circ}\) S). They used FPI measurements for 9 months (including 139 nights of usable data) obtained between the months of March to June 2016 and September 2017 to January 2018. Their results showed that the hourly zonal wind speeds were between \(-\)124 and 163 m/s, and that the meridional winds were between \(-\)70 and 95 m/s. Similar to most of the prior work in other parts of the region, the FPI measurements were compared to predictions of the HWM-14. The results showed that the HWM-14 most often reproduced the post-midnight meridional component better than for the pre-midnight component. There was good agreement between the FPI zonal wind measurements and corresponding HWM-14 predictions during the month of January 2018, but the model typically underestimated the FPI zonal wind speeds for the months in 2016 (March to June). A new feature of their study involved periodicity analysis of the daily maximum neutral wind speeds. The results revealed modal periods which are quasi 27 days and quasi-terannual, for both the zonal and meridional winds. [PERSON] et al. (2021) [7] explored neutral wind and ionized plasma coupling by using 11 nights of coincident neutral wind measurements and EPB (equatorial plasma bubble) speed measurements. Zonal neutral wind measurements were obtained from the Abuja FPI, while corresponding EPB speeds were derived from airglow observations of a co-located optical all-sky imager. This is one of the few studies in the African region that reported simultaneous measurements of thermospheric neutral winds and corresponding EPB speeds. Their results showed that the magnitudes of instantaneous zonal neutral wind speeds were between 30 and 300 m/s, while the zonal EPB speeds were between 15 and 400 m/s. They generally observed that both the neutral winds and the EPBs were faster during the early evening hours than towards the midnight hours. Their comparison of the neutral wind and EPB speeds showed a mixture of scenarios in which both speeds were comparable in some instances, the neutral winds were faster than the EPBs in other instances, and the EPBs were faster than the neutral winds in other instances. In the South African mid-latitude region, [PERSON] et al. (2022) [13] presented a climatology of night-time thermospheric neutral winds using FPI measurements from Sutherland, South Africa (Geographic: 32.2\({}^{\circ}\) S, 20.48\({}^{\circ}\) E; Geomagnetic: 40.7\({}^{\circ}\) S), obtained between the months of February 2018 and January 2019. Their results show that the annual meridional and zonal winds varied between \(-\)100 and 120 m/s, and that the wind measurements exhibited typical midlatitude nocturnal and seasonal variations. The meridional winds were mostly equatorward (northward) from dusk to predrawn during summer (December-February), while during the winter (July-August), the meridional winds were poleward (southward) from dusk, then turned equatorward around midnight. They noted that the zonal winds were typically eastward during the evenings until just before the midnights, and that they became westward after midnight. A comparison of the FPI measurements with corresponding predictions from the HWM-14 showed that the model predictions of the meridional winds were in better agreement with corresponding FPI measurements, compared to the zonal components.