New Insights into the Simultaneous Occurrence of Equatorial Counter Electrojet and Ionospheric Irregularities

Ionospheric irregularities can cause continuous intermittent loss or complete outage of trans-ionospheric radio signals which are an important part of space weather disturbances to a technological society. Recent studies show that the equatorial regions are also susceptible to disruptive space weather. We investigate the long-term relationship between equatorial counter electrojet and ionospheric plasma depletion in terms of total electron content (TEC), vertical drifts and equatorial spread-F (ESF) using coordinated multi-instrument observations (using magnetometers, GPS, radars, and ionosondes measurements). Here, we present the one-to-one correspondence between the occurrence characteristics of equatorial counter electrojet, the height of peak ionization in the F-layer, and ionospheric plasma depletions. It is investigated whether the occurrences of the morning counter electrojet might be either precursor or the remnant effects of nighttime plasma bubbles. Additionally, the possible drivers and occurrences of the morning counter electrojet and equatorial plasma bubbles (EPBs) under different level of geomagnetic conditions will also be discussed from statistical and theoretical perspectives. This result has significant implications for the modern society and research communities to deal with a wide range of space weather impacts on the systems of radio communication, navigation, and power grid infrastructure in the low-latitude regions.