On the spatiotemporal evolution of the ionospheric backscatter during magnetically disturbed periods as observed by the TIGER Bruny Island HF radar

Vickal Kumar, R Makarevich, Tom Kane, H Ye, John Devlin, Peter Dyson

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Abstract

The Superposed Epoch Analysis (SEA) method is used to examine a 4-year database (2000-2003) of the TIGER Bruny Island radar (MLON=226.78A?E, MLAT=55.06A?S) measurements to determine typical patterns of the spatiotemporal evolution of ionospheric backscatter during geomagnetically disturbed periods. SEA is performed separately for three disturbance categories: short-, medium-, and long-duration magnetic disturbances, based on the Dst index variation. Prior to SEA, the diurnal, seasonal, and solar cycle effects have been accounted for by subtracting the nominal quiet-time values. It is found that the occurrence of ionospheric HF backscatter exhibited strongest enhancements near t=0. h between 65A?S and 70A?S MLAT (range of 800-2500. km) during short-duration magnetic disturbance. In contrast, a reduction in echo occurrence first occurred near t=0. h at higher ranges (r 2500. km) and expanded equatorwards during the recovery phase of the magnetic disturbances. This reduction in occurrence became progressively stronger and prolonged for medium- and long-duration magnetic disturbances. These categories also showed clear enhancements in the E-region backscatter (r
Original languageEnglish
Pages (from-to)1940 - 1952
Number of pages13
JournalJournal of Atmospheric and Solar-Terrestrial Physics
Volume73
Issue number13
DOIs
Publication statusPublished - 2011
Externally publishedYes

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