Spatial and temporal correlations of thermospheric zonal winds from satellite observations

Thermospheric neutral winds play an important role in the transport of momentum and energy in the upper atmosphere and affect the composition, dynamics and morphology of the ionospheric plasma. Although the general morphology of the winds is well understood, we are only starting to understand its variability.

Data from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission were used in this study. The mission provided dawn and dusk cross-track (zonal) neutral winds at approximately 260 km of altitude. The zonal wind measurements from low and mid-latitudes were used to calculate spatial and temporal correlations during geomagnetically quiet periods. Correlations indicate a statistical relationship between the winds at different times and locations on the globe and provide insight into physical processes that produce variations in observations. They become very important for model validations, which involve comparisons of correlations obtained from observations with those obtained from the models. The correlations were computed during December solstice 2009 to 2012 and the year-to-year variability was investigated. December solstice 2009 and June solstice 2010 were also compared.