A Case Study of Polar Cap Sporadic-E Layer Associated with TEC Variations

Yong Wang,David R Themens,Shiva David,Periyadan T Jayachandran,Qing-He Zhang,Richard Chadwick,Anthony M Mccaffrey

doi:10.3390/rs13071324

Yong Wang, David R Themens + Show 5 more

Open Access

https://doi.org/10.3390/rs13071324

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Abstract

The Sporadic-E (Es) layer is an often-observed phenomenon at high latitudes; however, our understanding of the polar cap Es layer is severely limited due to the scarce number of measurements. Here, the first comprehensive study of the polar cap Es layer associated with Global Positioning System (GPS) Total Electron Content (TEC) variations and scintillations is presented with multiple measurements at Resolute, Canada (Canadian Advanced Digital Ionosonde (CADI), Northward-looking face of Resolute Incoherent-Scatter Radar (RISR-N), and GPS receiver). According to the joint observations, the polar cap Es layer is a thin patch structure with variously high electron density, which gradually develops into the lower E region (~100 km) and horizontally extends >200 km. Moreover, the TEC variations produced by the polar cap Es layer are pulse-like enhancements with a general amplitude of ~0.5 TECu and are followed by smaller but rapid TEC perturbations. Furthermore, the possible scintillation effects likely associated with the polar cap Es layer are also discussed. As a consequence, the results widely expand our understanding on the polar cap Es layer, in particular on TEC variations.

Highlights

The Sporadic-E (Es) layer is normally a thin layer with quite variable peak density at an altitude range of 90−120 km and is predominately composed of metallic ions deposited by meteor ablation into the ionosphere [1,2,3,4,5,6,7]
Referring to the formation mechanism of the Es layer at mid-latitudes, it is a widely accepted view that the vertical convergence of the metal ions is primarily driven by the wind shears [12,13,14,15,16]; at high latitudes the formation of the polar cap Es layer is not explained only by wind shears, as the almost vertical direction of magnetic field relegates this mechanism to a secondary formation source; as such, strong electric fields have been proposed as the dominate effect on drifting metallic ions [17,18]
A number of experiments corresponding to the polar cap Es layer were collected since