Winds in the ionosphere—A review

<i>F</i>-region ionospheric perturbations in the low-latitude ionosphere during the geomagnetic storm of 25-27 August 1987

“…effects of the E×B plasma drift on hmF 2 and N mF 2 over these sounders and over the MU radar are much less than those caused by the plasma drift due to the neutral wind. The HWW90 wind velocities are known to differ from observations (Titheridge, 1995 To give an example of changes in the meridional neutral wind due to W, the diurnal variations of the modeled meridional uncorrected HWW90 (dotted lines) and corrected (solid lines) neutral winds during 25-27 August 1987 at 300 km are shown in the middle and top panels over the MU radar and over the Darwin ionosonde station, respectively. We conclude that the storm-time meridional wind velocity has non-regular variations, in agreement with the early conclusions of Kawamura (2003), and the magnitude of the storm-time meridional wind shown by the solid line in the middle panel of Fig.…”

“…As far as the authors know, our investigation is the first theoretical study of the role of variations in the neutral winds, temperature, and densities in producing the north−south asymmetry in the storm-time electron density. Otsuka et al (1998) found that the occurrence and strength of the morning and evening peaks in T e over the MU radar depend on altitude, season, and solar activity under magnetically quiet conditions during 1986-1995. Pavlov et al (2004 studied, for the first time, the latitude dependence of the occurrence and strength of the morning and evening peaks in T e and the mechanisms causing these peaks in the lowlatitude ionosphere during geomagnetically quiet-time conditions of 19-21 March 1988.…”

Average daytime F region disturbance neutral winds measured by UARS: Initial results

“…Stormtime high latitude electric fields give rise to enhanced high latitude thermospheric winds and to increased Joule heating, which is the main driver of global disturbances in thermospheric composition, neutral and ion temperatures, and winds. The mid-and low-latitude thermospheric winds can be strongly affected by large scale storm time circulation or bulk advective processes, and by storm generated traveling atmospheric waves which propagate and interact globally Mid-and low-latitude thermospheric winds have been studied extensively using ground-based and in situ and remote sensing satellite data [e.g., Hagan, 1993;Titheridge, 1995;Buonsanto et al, 1999]. This has led to a reasonably In this study, we use extensive vector wind measurements by the WINDII instrument on board the UARS satellite to determine the average characteristics of the mid-and lowlatitude daytime F region disturbance winds.…”

A climatology of the F-layer equivalent winds derived from ionosonde measurements over two decades along the 120°-150°E sector

“…The HWM93 model predicts little longitudinal variations of the meridional winds except for high latitudes (Titheridge, 1995b). According to the work of Karpachev et al (2001), the longitudinal variation of vertical plasma drifts induced by neutral winds at the 120 • -150 • E sector is less than 10 m/s at mid-latitudes when meridional winds are large enough.…”

“…Finally, at night the EEWs are generally smaller by a magnitude of about 20 m/s in the Southern Hemisphere than in the Northern Hemisphere. This may be partly attributed to poor predictions of HWM93 in the Southern Hemisphere because of a sparse database, which has already been pointed out by many authors (Titheridge, 1995b;Miller et al, 1997). Another reason may be that the empirical electric field drift model is less reliable beyond equatorial and low latitudes.…”