Investigation of the response time of the equatorial ionosphere in context of the equatorial electrojet and equatorial ionization anomaly

摘要

Equatorial Electrojet (EEJ) and Equatorial Ionization Anomaly (EIA) are twolarge-scale processes in the equatorial/low latitude ionosphere, drivenprimarily by the eastward electric field during daytime. In the presentpaper we investigate the correlation between the Integrated EEJ strength(IEEJ) and the EIA parameters like the total electron content at thenorthern crest, location of crest in Magnetic latitude and strength of theEIA for the Indian sector. A good correlation has been observed between theIEEJ and EIA when a time delay is introduced between IEEJ and EIA parameters. This timedelay is regarded as the response time of equatorial ionosphere in contextof the evolution of EIA vis-à-vis EEJ. Further, a seasonal variation inthe time delay has been observed, which is believed to be due to changes inthermospheric wind. Using the response time and the linear relationshipobtained, the possibility of near-real time prediction of EIA parameters hasbeen attempted and found that the prediction holds well during thegeomagnetically quiet periods. The paper discusses these aspects in detail.