Abstract
Polar topside total electron content (TEC) enhancement (PTTE) above 1336
km altitude is reported for the first time. The results are based on
measurements from 2008 to 2018 made using a GPS receiver onboard NASA’s
Jason-2 satellite. The enhancement can exceed 5.5 TEC units or 78%
relative to the dayside ambient state. Comparisons with
COSMIC/FORMOSAT-3 topside TEC measurements confirm the PTTE events. Our
statistical analysis reveals that PTTE mostly occurs in the southern
dayside polar cap, with a seasonal preference of southern summer,
regardless of geomagnetic conditions. Our case analysis indicates that
PTTE is associated with the tongue of ionization. This suggests that the
source of PTTE may be the dayside F region plasma that moves poleward
following the anti-sunward plasma convection, and the plasma upflow
driven by the polar wind may act to cause PTTE. The hemispheric
asymmetry in PTTE occurrence remains to be a major unsolved puzzle.