An upper <i>E</i> region quarterdiurnal tide at Arecibo?

Tao, Yu; Mathews, J. D.; Ying, Weiyong

doi:10.1029/ja093ia09p10047

Cited by 53 publications

(48 citation statements)

References 8 publications

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“…Tong et al (1988) and Morton et al (1993) have confirmed that the existence of the 6-h tide exists in their investigations of the intermediate layer and meriodional winds. In these previous studies (Amayenc and Reddy, 1972;Morton et al, 1993), the quarter-diurnal tide was conceived as a high-order component of winds, which would influence the diurnal and semidiurnal components.…”

Section: Discussionmentioning

confidence: 53%

“…Early studies (Fujitaka and Tohmatsu, 1973;Mathews and Bekeny, 1979;Tong et al, 1988Szuszczewicz et al, 1995) examined the different tidal motions that occur in layer production. These studies indicated that the intermediate layer behavior is controlled mainly by the semi-diurnal and quarter-diurnal tides, but did not clarify the seasonal characteristics of tidal motions.…”

Section: Discussionmentioning

confidence: 99%

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The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region

et al. 2003

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Abstract. This investigation presents an initial attempt toanalyze a full year of daily ionosonde observations relevant to the determination of plasma densities, tidal structures, and ion transports in the equatorial anomaly region of the lower ionosphere. Particular focus is on the intermediate layers, their seasonal and diurnal variations, and cause-effect relationships. The ionogram database was recorded using a digisonde portable sounder (DPS) at National Central University (NCU, 24 • 58 N, 121 • 11 E) during 1996. Statistical results indicate that the intermediate layers appear primarily during the daytime of the spring/winter months. The monthly median height characteristics reveal that the layers descend from high to low altitudes and different tidal motions control the layers in different months. Generally, the semi-diurnal and quarter-diurnal tides, which cause ionization convergence, are mainly in the spring/winter and summer/autumn months, respectively. Variations in the electron densities of the layers also indicate that the density increases could result from a great number of molecular and metallic ions. Furthermore, a novel approach to ionogram presentation is introduced to investigate the intermediate layers. This approach allows the DPS to characterize the detailed daily information of the intermediate layers.

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Section: Discussionmentioning

confidence: 53%

Section: Discussionmentioning

confidence: 99%

The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region

et al. 2003

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“…Another important and interesting aspect of the descending echoing region is the occurrence of echoes at altitudes as low as 87 km. Dynamics of E region layers in the height region of 80-160 km has been extensively studied both experimentally and theoretically over Arecibo (Mathews and Bekeny, 1979;Tong et al, 1988) and more recently using ionosonde at Milos (Haldoupis et al, 2006). Arecibo observations showed that the layer could come down to altitude as low as 85 km.…”

Section: Descending Echoing Layer and Relevance Of Tidal Ion Layermentioning

confidence: 99%

Gadanki radar observations of daytime E region echoes and structures extending down to 87 km

et al. 2006

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Abstract.Observations of daytime E region echoes extending to altitudes as low as 87 km made using the Gadanki MST radar are presented. The echoing regions display descending layer resembling the characteristics of tidal winds and show structures with periods 2-4 min having both positive and negative slopes. At the center of the layer where strongest SNR is observed, the velocity is maximum and spectral width is minimum. At altitudes slightly above and below, where SNR is relatively low, velocity is low but spectral width is maximum. Daytime observations of echoes extending to such a low altitude and associated structures akin to nighttime quasi-periodic echoes throughout the observational period are the most significant results, not reported earlier from Gadanki and other locations. Other notable results are large SNR (as high as 15 dB) and spectral width (as high as 70 m/s) at the bottommost altitudes, where collisional damping of the plasma waves is significant.

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“…The model components consist of the mean, diurnal and semidiurnal tidal winds described in Forbes (1982a, b), with some adjustments so as to reproduce average observed winds over Arecibo for non-winter conditions (Harper, 1981). An alternative wind model Tong et al, 1988), applicable to January conditions over Arecibo and which contains a 6-h tidal component, was evaluated against the Forbes/ Harper model. Since both exhibited similar descending and stagnation phases for the convergent nulls responsible for layer formation, only results for the Forbes/ Harper model are presented here.…”

Section: Other Model Inputsmentioning

confidence: 99%

Global transport and localized layering of metallic ions in the upper atmospherer

Carter

Forbes

1999

Ann. Geophys.

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Abstract. A numerical model has been developed which is capable of simulating all phases of the life cycle of metallic ions, and results are described and interpreted herein for the typical case of Fe + ions. This cycle begins with the initial deposition of metallics through meteor ablation and sputtering, followed by conversion of neutral Fe atoms to ions through photoionization and charge exchange with ambient ions. Global transport arising from daytime electric ®elds and poleward/ downward diusion along geomagnetic ®eld lines, localized transport and layer formation through descending convergent nulls in the thermospheric wind ®eld, and ®nally annihilation by chemical neutralization and compound formation are treated. The model thus sheds new light on the interdependencies of the physical and chemical processes aecting atmospheric metallics. Model output analysis con®rms the dominant role of both global and local transport to the ion's life cycle, showing that upward forcing from the equatorial electric ®eld is critical to global movement, and that diurnal and semidiurnal tidal winds are responsible for the formation of dense ion layers in the 90±250 km height region. It is demonstrated that the assumed combination of sources, chemical sinks, and transport mechanisms actually produces F-region densities and E-region layer densities similar to those observed. The model also shows that zonal and meridional winds and electric ®elds each play distinct roles in local transport, whereas the ion distribution is relatively insensitive to reasonable variations in meteoric deposition and chemical reaction rates.

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An upper E region quarterdiurnal tide at Arecibo?

Cited by 53 publications

References 8 publications

The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region

The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region

Gadanki radar observations of daytime E region echoes and structures extending down to 87 km

Global transport and localized layering of metallic ions in the upper atmospherer

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