Global Structure and Seasonal Variations of the Tidal Amplitude in Sporadic‐E Layer

Tang, Qiong; Zhou, Chen; Liu, Huixin; Du, Zheyuan; Liu, Yi; Zhao, Jiaqi; Yu, Zhibin; Zhao, Zhengyu; Feng, Xueshang

doi:10.1029/2022ja030711

Cited by 4 publications

(4 citation statements)

References 46 publications

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“…The diurnal variation prevails at lower latitudes, while the semidiurnal variation takes precedence at mid-latitudes. These findings align with prior research, attributing these patterns to the influence of tides on neutral horizontal winds [7,12,15,37].…”

Section: The Descending Rates Of Es Layers and Ivnsupporting

confidence: 89%

“…At the same time, the descent rate of Es layers was estimated to be between 0.9-1.6 km/h based on the occurrence rate derived from COSMIC data [12]. With the help of ionosondes and COSMIC, the signals of tide and planetary waves in the strength and height of Es were found [13][14][15] and were connected with the variations of atmospheric waves [16,17].…”

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: Introductionmentioning

confidence: 99%

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

Yu,

Qiu

et al. 2023

Remote Sensing

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“…These 12‐ and 24‐hr periodicities have been recognized on Es formation in ionosonde measurements (Haldoupis, 2011, and more references therein). Diurnal (semidiurnal) tides are known to be stronger at low‐ (mid) latitude region compared to mid (low) latitudes and dominates the Es layers below (above) 120 km (Chu et al., 2014; Manson et al., 1999; Tang et al., 2022). From RO measurements, Chu et al.…”

Section: Results and Analysismentioning

confidence: 99%

“…Additionally, Tang et al. (2022) observed that the Es layer intensity is modulated by the semidiurnal tide from −25° to −65° and from 20° to 60° latitudes, while the diurnal tide modulates the Es layer intensity in the latitude range between ±20°. It is observed in this work that stronger power spectrum at 24‐hr compared to 12‐hr in Figure 8, except in autumn where the peak is narrowest.…”

Section: Results and Analysismentioning

confidence: 99%

Analysis of Blanketing Sporadic‐E Layer and Associated Tidal Periodicities Over a Brazilian Station Undergoing a Transition From Low Latitude to Midlatitude

Moro,

Xu,

Bageston

et al. 2023

JGR Space Physics

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Analyses on a complete year of Digisonde data are conducted to investigate the sporadic‐E (Es) layers over Santa Maria (29.7°S, 53.8°W, dip lat.: −37°), Brazil. This region is undergoing a transition from low latitude to midlatitude within the South American Magnetic Anomaly (SAMA), which provides a key motivation to explore their behavior and the associated tidal periodicities. The Es are classified into four types: flat (Esf), low (Esl), high (Esh), and cusp (Esc). The diurnal and seasonal variations of their top (ftEs) and blanketing (fbEs) frequencies and virtual height (h′Es) are examined. The frequency parameters show the presence of intense Es during equinoxes besides summer. It is also remarkable that the higher values of mean h′Es during winter compared to the other seasons during daytime. These observations differ from previous theories about midlatitude Es layers. The diurnal occurrence rates of the Esb types exhibited distinct dependencies on both local time and seasons. The Esh and Esc were observed exclusively during the daytime, with the former dominating the occurrences in all seasons. To investigate any tidal periodicities embedded in the ftEs, fbEs, and h′Es time series, the Lomb‐Scargle technique was employed. The analysis revealed the presence of 24‐, 12‐, 8‐, and 6‐hr periodicities in both fbEs and h′Es when considering the entire year of data. However, when the data are fractioned into seasons, the predominant periodicities were found to be 24‐ and 12‐hr cycles. Furthermore, when considering the different Esb types, the Lomb‐Scargle analysis indicated varying periodicities.

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The Characteristics and Simulation of Sporadic E Layers in Ascending and Descending Phases of the Solar Cycle at Mid‐Latitude Stations

Zhang,

Peng,

Jin

et al. 2024

JGR Space Physics

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Most of the attention was paid to the correlation between Sporadic E (Es) layers and solar activity, and conflicting conclusions were obtained in previous research. For the first time, we analyze the influence of solar activity on the number of Es layer traces (Es layers with a certain duration and intensity), the lifetime and descent velocity of the descending Es layer traces, and the results have been explained using simulation based on windshear theory and Lomb‐Scargle (LS) spectral analysis. A statistical analysis of Es layers observed in ascending (2010–2012) and descending (2016–2018) phases of the solar cycle is presented at three different mid‐latitude stations of Kuming (25.5°N, 103.8°E), Lanzhou (36.1°N, 103.9°E) and Urumqi (43.8°N, 87.6°E) in China region. The observation results indicate that the occurrence rate, height distribution and the number of the Es layer traces are all influenced by solar activity, indicating that they are negatively correlated with solar activity. The simulation, spectral analysis, and observations reveal that the lifetime and descent velocity of the descending Es layer traces are mainly modulated by semidiurnal and diurnal tides, but are less affected by solar activity. The predominant oscillations of the Es layer are identified using LS spectral analysis. The spectral analysis reveals that the modulation of diurnal tide waves on Es layers dominates at lower mid‐latitudes, and that of semidiurnal tide waves dominates at higher latitudes. The results also confirm the modulation of planetary waves on Es layers at different mid‐latitudes.

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Global Structure and Seasonal Variations of the Tidal Amplitude in Sporadic‐E Layer

Cited by 4 publications

References 46 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

Analysis of Blanketing Sporadic‐E Layer and Associated Tidal Periodicities Over a Brazilian Station Undergoing a Transition From Low Latitude to Midlatitude

The Characteristics and Simulation of Sporadic E Layers in Ascending and Descending Phases of the Solar Cycle at Mid‐Latitude Stations

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