Numerical Investigation on the Height and Intensity Variations of Sporadic E Layers at Mid‐Latitude

Qiu, Lihui; Yamazaki, Yosuke; Yu, Tao; Miyoshi, Yasunobu; Zuo, Xiaomin

doi:10.1029/2023ja031508

Cited by 3 publications

(9 citation statements)

References 69 publications

(92 reference statements)

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“…These findings highlight the consistency between the variations in IVN height and Es occurrence. The results of this study suggest that Es layers occur at the height of IVN and are dragged down by IVN, aligning with the results reported by Qiu [22]. Simulation studies propose that a thin, high-density metal ion layer, generated under the wind shear theory, stabilizes at roughly the height of IVN within thirty minutes [22,23].…”

Section: The Descending Rates Of Es Layers and Ivnsupporting

confidence: 89%

“…The results of this study suggest that Es layers occur at the height of IVN and are dragged down by IVN, aligning with the results reported by Qiu [22]. Simulation studies propose that a thin, high-density metal ion layer, generated under the wind shear theory, stabilizes at roughly the height of IVN within thirty minutes [22,23]. It is worth noting that Es layers will be stationary while Es layers are down below 100 km in Figure 4.…”

Section: The Descending Rates Of Es Layers and Ivnsupporting

confidence: 89%

“…This demarcates the altitude where ions come to a standstill and can also be considered the altitude where Es layers are stationed. Numerical simulations suggested that the height of the Es layer agrees well with the height of the IVN above 110 km [22]. A theoretical study by Dalakishvili et al (2020) also suggested that the height of the Es layer is in closer proximity to the height of IVN [23].…”

Section: Introductionmentioning

confidence: 75%

“…This implies the presence of a thin ion layer undergoing vert motion, deviating from the height of VICmax. According to the simulation findi [22,23], the Es layer is expected to manifest at the height of IVN. In scenarios where I is absent, Es would emerge at the height of VICmax and subsequently move toward height where both the vertical ion velocity and vertical ion convergence approach ze Thus, in theory, Es is more closely aligned with the height of IVN.…”

Section: Comparison Of the Heights Of Es Layers And Vertical Ion Conv...mentioning

confidence: 96%

“…Through a combination of observations and modeling, it has been affirmed that there is a significant correlation between VIC, Es occurrence rate (EsOR), and Es intensity in their global distribution, seasonal variations, and local time variations [10,12,[19][20][21]. Previous studies have employed two main parameters (i.e., the maximum positive value of vertical ion convergence (VICmax) and ion vertical velocity null (IVN)) to assess the height of Es layers [11,12,[22][23][24]. The VICmax is the point that has a maximum positive value of vertical ion convergence.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the Heights of Sporadic E Layers and Vertical Ion Convergence Parameters

Yu,

Qiu

et al. 2023

Remote Sensing

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Sporadic E (Es) layers are thin layers of enhanced electron density that commonly appear at altitudes of 90–130 km, often impacting radio communications and navigation systems. The wind shear theory posits that the vertical ion drift, influenced by atmospheric neutral winds and the magnetic field, serves as a significant dynamic driver for the formation and movement of Es layers. In current studies, both the heights of ion vertical velocity null (IVN) and the maximum vertical ion convergence (VICmax) have been proposed as the potential height of Es layer occurrence. In this study, utilizing the neutral atmospheric wind data derived from the WACCM-X (The Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension), we computed and compared these two parameters with the observed Es layer heights recorded by the FORMOSAT-3/COSMIC (FORMOsa SATellite-3/Constellation Observing System for Meteorology, Ionosphere, and Climate) radio occultation (RO) observations. The comparative analysis suggests that IVN is a more likely node for Es layer occurrence than VICmax. Subsequently, we examined the height–time distributions of IVN and Es layers, as well as their respective descent rates at different latitudes. These results demonstrated a notable agreement in height variations between IVN and Es layers. The collective results presented in this paper provide strong support that the ion vertical velocity null plays a crucial role in determining the height of Es layers.

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Section: The Descending Rates Of Es Layers and Ivnsupporting

confidence: 89%

Section: The Descending Rates Of Es Layers and Ivnsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 75%

Section: Comparison Of the Heights Of Es Layers And Vertical Ion Conv...mentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Comparison of the Heights of Sporadic E Layers and Vertical Ion Convergence Parameters

Yu,

Qiu

et al. 2023

Remote Sensing

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Enhanced Sporadic E Layer and Its Perturbations During the 2022 Hunga Volcanic Eruption

Qiu,

Liu,

et al. 2024

Space Weather

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Sporadic E (Es) layers are plasma irregularities significantly affecting radio communication and navigation systems. And, their dominant formation mechanism at mid‐latitudes, known as the wind shear theory, suggests that they serve as indicators of the atmosphere‐ionosphere coupling processes in the mesosphere and lower thermosphere region. On 15 January 2022, the Hunga Tonga‐Hunga Ha'api submarine volcanic eruption provided a unique opportunity to investigate the Es layer responses to lower atmospheric perturbations. Using the FORMOSAT‐7/COSMIC‐2 radio occultation and ground‐based ionosonde observations, this study reveals the spatial‐temporal behaviors of the Es layers after the Hunga volcanic eruption. The results show that significant Es layer perturbations occurred over the northwest of the epicenter ∼4 hr after the eruption and lasted for approximately ∼22 hr. We also calculated the geographical distribution of the vertical ion convergence (VIC) using neutral winds obtained from the Michelson Interferometer for Global High‐resolution Thermospheric Imaging on the Ionospheric Connection Explorer (ICON) satellite. A comparison of the geographical distribution of positive VIC and Es layer perturbations shows a good agreement, which indicates that the enhanced Es layers are caused by strong VIC associated with the atmospheric perturbations due to the eruption. This study presents observational evidence for coupling between the Es layer and lower atmospheric perturbations, which can be helpful for understanding the occasionality and variability of Es layer occurrence.

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Planetary Wave Signature in Low Latitude Sporadic E Layer Obtained From Multi‐Mission Radio Occultation Observations

Sobhkhiz‐Miandehi,

Yamazaki,

Arras

et al. 2024

Earth and Space Science

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The Sporadic E layer or Es is an ionospheric phenomenon characterized by enhancements in electron density within 90–120 km above the Earth's surface. Based on the wind shear theory, the formation of Es layers is associated with vertical shears in the horizontal wind, in the presence of the Earth's magnetic field. This study explores the role of planetary waves on inducing these vertical shears and subsequently shaping Es layers. Our investigations benefit from a large amount of data facilitated by the FORMOSAT‐7/COSMIC2 and Spire missions, which offer extensive global coverage. A wave analysis is applied to the Es intensity as represented by the S4 index derived from radio occultation measurements, in search of potential planetary wave signatures. Additionally, measurements from Aura/MLS are used to analyze corresponding spectra for the geopotential height, enabling a comparative examination of planetary wave signatures in the Es layer and geopotential height variations. The findings reveal westward and eastward wave components with specific wavenumbers and periods, suggesting the involvement of westward propagating quasi 6‐day, quasi 4‐day planetary waves, and eastward propagating Kelvin waves with a period of around 3 days in Es layer formation at low latitudes.

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Numerical Investigation on the Height and Intensity Variations of Sporadic E Layers at Mid‐Latitude

Cited by 3 publications

References 69 publications

Comparison of the Heights of Sporadic E Layers and Vertical Ion Convergence Parameters

Comparison of the Heights of Sporadic E Layers and Vertical Ion Convergence Parameters

Enhanced Sporadic E Layer and Its Perturbations During the 2022 Hunga Volcanic Eruption

Planetary Wave Signature in Low Latitude Sporadic E Layer Obtained From Multi‐Mission Radio Occultation Observations

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