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

摘要

Positive ionospheric storm effects that occurred duringthe superstorm on 20 November 2003 are investigated using a combination ofground-based Global Positioning System (GPS) total electron content (TEC),and the meridian chain of ionosondes distributed along the Latin Americalongitude of ~280° E. Both the ground-based GPS TEC and ionosondeelectron density profile data reveal significant enhancements at mid-lowlatitudes over the 280° E region during the main phase of the November2003 superstorm. The maximum enhancement of the topside ionospheric electroncontent is 3.2–7.7 times of the bottomside ionosphere at the locations ofthe ionosondes distributed around the mid- and low latitudes. Moreover, theheight of maximum electron density exceeds 400 km and increases by 100 kmcompared with the quiet day over the South American area from middle to lowlatitudes, which might have resulted from a continuous eastward penetrationelectric field and storm-generated equatorward winds. Our results do notsupport the conclusions of Yizengaw et al. (2006), who suggested that the observed positivestorm over the South American sector was mainly the consequence of thechanges of the bottomside ionosphere. The so-called "unusual" responses ofthe topside ionosphere for the November 2003 storm in Yizengaw et al. (2006) are likelyassociated with the erroneous usage of magnetometer and incomplete data.