https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL076572

Investigation of the Electron Density Variation During the 21 August 2017 Solar Eclipse

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2017JA024927

Longitudinal Structure of the Midlatitude Ionosphere Using COSMIC Electron Density Profiles

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2017JA025048

Statistical Behavior of the Longitudinal Variations of the Evening Topside Mid-Latitude Trough Position in both Northern and Southern Hemispheres

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JA025551

MENTAT: A New Wind Model for Earth's Thermosphere

Climatology analysis of the daytime topside ionospheric diffusive O+ flux based on incoherent scatter radar observations at Millstone Hill

This paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30° to 120°W geographic longitude and 50° to 75°S geographic latitude at solar minimum between 2007 and 2010 This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data It is shown that the commonly accepted explanation that the WSA is related to the magnetic field declination and inclination effects on the neutral wind does not explain the longitudinal variation of the electron density Rather, longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the WSA These longitudinal wind and density changes are attributed to the varying latitudinal distance from the auroral zone energy input No contributions from the plasmasphere or other sources are required Furthermore, it is shown that a widely used empirical thermosphere density model overestimates the longitudinal changes in the WSA region

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2016JA023565

Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

This paper investigates the causes of the sudden descent (midnight collapse) of the ionosphere at Townsville, Australia during the equinox periods of years between 1970 to 1980. The collapse of hmF2 at midnight is found to occur on 89% of the 330 equinox nights that are investigated, and the mean magnitude of the midnight collapse is 84 km in the March equinox periods and 99 km in the September equinox periods. Observations of hmF2 are used to determine equivalent meridional neutral winds using a first-principles physics model. Harmonic analysis of these derived winds reveals the existence of significant diurnal (24-hour), semidiurnal (12-hour), and terdiurnal (8-hour) tidal components. The contribution of wind harmonics to the midnight collapse is determined by bandpass filtering the winds to only allow certain tides and then modeling their effect on hmF2 near midnight. The results indicate that the diurnal, semidiurnal and terdiurnal components of the meridional neutral wind all play a significant role at various times, but the effect of the 6-hour wind component is minimal. The spectral analysis also reveals that the terdiurnal wind component becomes dominant during solar maximum. Electric fields do not appear to be responsible for the midnight hmF2 collapse because it is seldom seen at the near-conjugate station of Akita, Japan.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015JA021842

P. B. Dandenault

Papers

Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

The Collapse of the Midnight Ionosphere and Behavior of Meridional Neutral Winds at Townsville Over a Full Solar Cycle