Unusual topside ionospheric density response to the November 2003 superstorm

Abstract

[1] We use observations from a variety of different ground-and space-based instruments, including ionosonde, ground-and space-based Global Positioning System (GPS) receivers, magnetometers, and solar wind data from the Advanced Composition Explorer (ACE), to examine the response of the ionospheric F2-layer height during the November 2003 superstorm. We found that the topside ionosphere responded unusually to the 20 November 2003 severe storm compared to behavior observed in a number of previous storms. While ground-based GPS receivers observed a large enhancement in dayside TEC, the low-Earth orbiting ($400 km) CHAMP satellite did not show any sign of dayside TEC enhancement. The real-time vertical density profiles, constructed from ground-based GPS TEC using a tomographic reconstruction technique, clearly revealed that the ionospheric F2-layer peak height had been depressed down to lower altitudes. Ionospheric F-layer peak height (hmF2) from the nearby ionosonde stations over Europe also showed that the dayside F2-layer peak height was below 350 km, which is below the orbiting height of CHAMP. The vertical E Â B drift (estimated from ground-based magnetometer equatorial electrojet delta H) showed strong dayside downward drifts, which may be due to the ionospheric disturbance dynamo electric field produced by the large amount of energy dissipation into high-latitude regions. This storm demonstrates that data from LEO satellites varies widely among different superstorms.

Positive ionospheric storm effects at Latin America longitude during the superstorm of 20–22 November 2003: revisit

“…Moreover, the height of maximum electron density exceeds 400 km and increases by 100 km compared with the quiet day over the South American area from middle to low latitudes, which might have resulted from a continuous eastward penetration electric field and storm-generated equatorward winds. Our results do not support the conclusions of Yizengaw et al (2006), who suggested that the observed positive storm over the South American sector was mainly the consequence of the changes of the bottomside ionosphere. The so-called "unusual" responses of the topside ionosphere for the November 2003 storm in Yizengaw et al (2006) are likely associated with the erroneous usage of magnetometer and incomplete data.…”

“…Our results do not support the conclusions of Yizengaw et al (2006), who suggested that the observed positive storm over the South American sector was mainly the consequence of the changes of the bottomside ionosphere. The so-called "unusual" responses of the topside ionosphere for the November 2003 storm in Yizengaw et al (2006) are likely associated with the erroneous usage of magnetometer and incomplete data. …”

“…For the superstorm of 20 November 2003, Yizengaw et al (2006) reported that the topside ionosphere responded unusually as compared to the behaviour observed in a number of other storms. In Yizengaw et al (2006), the vertical density profiles, constructed from ground-based GPS TEC using a tomographic reconstruction technique, revealed that the ionospheric F2-layer peak height in the mid-low latitude areas of the Southern Hemisphere at 290 • E had been depressed down to altitudes below the orbiting height of the CHAMP satellite (∼400 km).…”

“…In Yizengaw et al (2006), the vertical density profiles, constructed from ground-based GPS TEC using a tomographic reconstruction technique, revealed that the ionospheric F2-layer peak height in the mid-low latitude areas of the Southern Hemisphere at 290 • E had been depressed down to altitudes below the orbiting height of the CHAMP satellite (∼400 km). Furthermore, Yizengaw et al (2006) showed that the daytime topside ionospheric contribution to the ground-based GPS TEC is usually low (<20 %), a percentage which is far less than the large increase of the topside ionosphere observed during the 2003 Halloween storm. Mannucci et al (2005) observed a ∼900 % increase in electron content above the CHAMP satellite at ±30 • geomagnetic latitudes over the Pacific Ocean.…”

“…In this paper, we re-investigated the ionospheric response in the mid-low latitudes at 290 • E longitude on the basis of the observations from ground GPS network and an ionosonde meridional chain during the November 2003 storm which was studied by Yizengaw et al (2006). Our observations show that the topside ionosphere in the South American longitude sector contributes a significant increment of TEC during the November 2003 storm, a typical feature during an intense magnetic storm, which is contrary to the results of Yizengaw et al (2006).…”