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Meteor and auroral drift measurements by P. Prikryl et al. (Radio Sci., 21, 271, 1986) and theoretical estimates by G.C. Reid (Radio Sci., 18, 1028, 1983) suggest that sufficiently large electric fields may decouple meteor trail electron motions from that of the neutral gas, leading to erroneous measurement of the neutral wind during sufficiently disturbed conditions. In the present study, we seek evidence of such effects by comparing hourly meteor radar wind measurements V_N near 95 km over South Pole with overhead F-region drifts V, measured by the SuperDARN radar at Halley (76° S, 27° W). Within the parameter space of our data set, we find no relationship between V_1 and the zonal wavenumber s = 0 and s = 1 components of V_N, and only a weak relationship for the wind residuals from the combined s = 0 and s = 1 wind field. For the latter, an inferred wind residual of 5.8ms^ is implied for an F-region plasma drift of 1000ms^ (E-field &thkzp; 70mVm^). This value of 5.8 ms^ falls within the 2 to 20ms^ range of plasma drifts expected to be induced at 95km by F-region E-fields ranging between 20 and lOOmVm^ by G.C. Reid (ibid, 1983). Thus, we cannot discount the possibility that this inferred wind is actually a plasma drift. In any case, we conclude that electric field contamination of previous scientific analyses with this data set which focused on the s = 0 and s = 1 components of the wind field, are negligible. Future experimental and modeling work is required to ascertain the degree to which .E-field induced effects on winds inferred from advection of meteor trails exist under more extreme conditions, or perhaps over shorter time scales.

The cloud imaging and particle size (CIPS) experiment is one of three instruments on board the Aeronomy of Ice in the Mesosphere (AIM) spacecraft that was launched into a 600 km Sun‐synchronous orbit on 25 April 2007. CIPS images have shown distinct wave patterns and structures in polar mesospheric clouds (PMCs), around the summertime mesopause region, which are qualitatively similar to structures seen in noctilucent clouds (NLCs) from ground‐based photographs. The structures in PMC are generally considered to be manifestations of upward propagating atmospheric gravity waves (AGWs). Variability of AGW effects on PMC reported at several lidar sites has led to the notion of longitudinal differences in this relationship. This study compares the longitudinal variability in the CIPSobserved wave occurrence frequency with CIPS‐measured PMC occurrence frequency and albedo along with mesospheric temperatures measured by the sounding of the atmosphere using broadband emission radiometry instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics spacecraft. Our results for the latitude ranges between 70° and 80° show a distinct anticorrelation of wave structures with cloud occurrence frequency and correlations with temperature perturbations for at least two of the four seasons analyzed, supporting the idea of gravity wave‐induced cloud sublimation. The locations of the observed wave events show regions of high wave activity in both hemispheres. In the Northern Hemisphere, while the longitudinal variability in observed wave structures show changes from the 2007–2008 seasons, there exist regions of both low and high wave activities common to the two seasons. These persistent features may explain some of the observed differences in PMC activity reported by ground‐based lidar instruments distributed at different longitudes. The statistical distribution of horizontal scales increases with wavelength up to at least 250 km. We also discuss the possibility of atmospheric tides, especially the nonmigrating semidiurnal tide, aliasing our observations and affecting the results presented in this analysis.