Statistical Analysis of Equatorial Plasma Bubbles Climatology and Multi‐Day Periodicity Using GOLD Observations

Abstract

This study develops a new Bubble Index to quantify the intensity of 2‐D postsunset equatorial plasma bubbles (EPBs) in the American/Atlantic sector, using Global‐scale Observations of the Limb and Disk (GOLD) nighttime data. A climatology and day‐to‐day variability analysis of EPBs is conducted based on the newly‐derived Bubble Index with the following results: (a) EPBs show considerable seasonal and solar activity dependence, with stronger (weaker) intensity around December (June) solstice and high (low) solar activity years. (b) EPBs exhibit opposite geomagnetic activity dependencies during different storm phases: EPBs are intensified concurrently with an increasing Kp, but are suppressed with high Kp occurring 3–6 hr earlier. (c) For the first time, we found that EPBs' day‐to‐day variation exhibited quasi‐3‐day and quasi‐6‐day periods. A coordinated analysis of Ionospheric Connection Explorer (ICON) winds and ionosonde data suggests that this multi‐day periodicity was related to the planetary wave modulation through the wind‐driven dynamo.

Quasi 6‐Day Planetary Wave Oscillations in Equatorial Plasma Irregularities

“…Additional shorter-period spectral peaks are seen at a period of ∼3day in early and mid-February. The ∼3-day spectral peaks are likely related to the quasi-three day planetary wave as discussed in Aa et al (2023). The S/G Only case exhibits spectral peaks around 4-8 days multiple times in January and February, with maxima around day of year 10, 25, and 40-45.…”

“…This includes notable day-to-day changes in the occurrence (or absence) of EPBs, the EPB longitudinal spacing, and the width of the EPBs (Aa et al, 2020;Eastes et al, 2019;Karan et al, 2020Karan et al, , 2023Martinis et al, 2021). Multi-day periodic behavior of EPBs has also been observed by GOLD, which was attributed to the influence of atmospheric planetary waves modulating the E-region dynamo (Aa et al, 2023).…”

Significant Midlatitude Bubble‐Like Ionospheric Super‐Depletion Structure (BLISS) and Dynamic Variation of Storm‐Enhanced Density Plume During the 23 April 2023 Geomagnetic Storm

“…15 min temporal resolution (e.g., Aa et al, 2020Aa et al, , 2022Aa, Zhang, Liu, et al, 2023;Cai et al, 2021Cai et al, , 2022Cai et al, , 2023Eastes et al, 2020;Karan et al, 2020). In addition, we use in-situ electron density measurements from the polarorbiting Swarm B satellite at an altitude of ∼500 km.…”

“…In this study, we use the nighttime disk measurements of OI 135.6 nm emission. These measurements provide continuous images in the local early evening hours, offering insights into the spatial‐temporal variations of equatorial and low‐latitude ionospheric dynamics from West African to South American longitude sectors with 15 min temporal resolution (e.g., Aa et al., 2020, 2022; Aa, Zhang, Liu, et al., 2023; Cai et al., 2021, 2022, 2023; Eastes et al., 2020; Karan et al., 2020). In addition, we use in‐situ electron density measurements from the polar‐orbiting Swarm B satellite at an altitude of ∼500 km.…”

Significant Mid‐ and Low‐Latitude Ionospheric Disturbances Characterized by Dynamic EIA, EPBs, and SED Variations During the 13–14 March 2022 Geomagnetic Storm

“…In this study, we use the nighttime 2-D disk images of OI 135.6 nm emission that is proportional to the square of F-region peak density. GOLD provides continuous time-evolving maps in the early evening hours to unambiguously reveal the spatial-temporal variation of EIA and EPB structures from West Africa to America (e.g., Aa et al, 2020Aa et al, , 2022Aa et al, , 2023Cai, Burns, Wang, Qian, Liu, et al, 2021;Cai et al, 2022Cai et al, , 2023Eastes et al, 2019). Moreover, we also use the GOLD column density ratio of O/N 2 to analyze the thermospheric composition variations, which is derived from the daytime disk measurements of OI 135.6 nm and the N 2 Lyman-Birge-Hopfield (LBH) emission (Strickland et al, 1995).…”