Atmospheric gravity waves generated in the high‐latitude ionosphere: A review

Hunsucker, R. D.

doi:10.1029/rg020i002p00293

Cited by 648 publications

(615 citation statements)

References 95 publications

(37 reference statements)

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“…Long-period¯uctuations of the virtual heights are observed, appearing ®rst and with the strongest amplitude at high altitudes, corresponding to the largest frequencies. Hunsucker (1982) has presented a review on atmospheric gravity waves (AGWs) and their ionospheric manifestation as travelling ionospheric disturbances (TIDs) and Georges (1967) has presented several examples of TIDs, as observed with ionosondes, very similar to the data presented in Fig. 8a.…”

Section: Ionosonde F-layer Datamentioning

confidence: 71%

Decameter mid-latitude sporadic-E irregularities in relation with gravity waves

Bourdillon¹,

Lefur²,

Haldoupis

et al. 1997

Ann Geophysicae

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Abstract. HF radar observations of mid-latitude sporadic-E irregularities carried out with the Valensole radar in South France are compared with simultaneous ionosonde measurements underneath the irregularity zones. In a previous study of Valensole radar data, it has been shown that HF backscatter from the night-time mid-latitude E region is usually associated with largescale wave-like modulations. To obtain more information on the geophysical conditions prevailing during backscatter events, a new experiment was performed which also included a vertical ionosonde beneath the scattering region. The data to be presented here are from two periods when radar scattering appeared simultaneously with large variations in the virtual height and the Doppler velocity of F-layer re¯ected echoes measured with the vertical ionosonde, indicating very clearly the passage of atmospheric gravity waves (AGWs). The e ect of the atmospheric waves on the sporadic-E layer is not always as marked as it is in the F region. In the ®rst event, the passage of the AGWs is accompanied by an upward followed by a downward movement of the Es-layer. The apparent descending movement of the Es-layer from 135 to 110 km in less than 10 min corresponded to a positive (downward) Doppler velocity of 35 m/s measured by the vertical ionosonde, and was accompanied by a range variation in the radar scattering region with a negative rate of about 90±110 m/s. In the second event, the Es-layer is not as strongly disturbed as in the previous one, but, nevertheless, the range variations of the scattering region can still be associated with height¯uctuations of the Es-layer.

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Section: Ionosonde F-layer Datamentioning

confidence: 71%

Decameter mid-latitude sporadic-E irregularities in relation with gravity waves

Bourdillon¹,

Lefur²,

Haldoupis

et al. 1997

Ann Geophysicae

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“…This creates a cooling spot in the stratosphere which moves with the supersonic speed across the Earth and creates continuous GWs. The WLS can also occur due to traveling ionospheric disturbances (TIDs) caused by geomagnetic storm at high latitude which can travel to middle and low latitudes [Francis, 1975;Hunsucker, 1982;Vlasov et al, 2011]. The TIDs are very unlikely to be the possible sources of WLS presented here as 22 July 2009 storm was a moderate geomagnetic storm.…”

Section: 1002/2013ja019521mentioning

confidence: 86%

Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

Maurya¹,

Phanikumar

Singh³

et al. 2014

JGR Space Physics

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We present first report on the periodic wave-like signatures (WLS) in the D region ionosphere during 22 July 2009 total solar eclipse using JJI, Japan, very low frequency (VLF) navigational transmitter signal (22.2 kHz) observations at stations, Allahabad, Varanasi and Nainital in Indian Sector, Busan in Korea, and Suva in Fiji. The signal amplitude increased on 22 July by about 6 and 7 dB at Allahabad and Varanasi and decreased by about 2.7, 3.5, and 0.5 dB at Nainital, Busan, and Suva, respectively, as compared to 24 July 2009 (normal day). The increase/decrease in the amplitude can be understood in terms of modal interference at the sites of modes converted at the discontinuity created by the eclipse intercepting the different transmitter-receiver great circle paths. The wavelet analysis shows the presence of WLS of period~16-40 min at stations under total eclipse and of period~30-80 min at stations under partial eclipse (~85-54% totality) with delay times between~50 and 100 min at different stations. The intensity of WLS was maximum for paths in the partially eclipsed region and minimum in the fully eclipsed region. The features of WLS on eclipse day seem almost similar to WLS observed in the nighttime of normal days (e.g., 24 July 2009). The WLS could be generated by sudden cutoff of the photo-ionization creating nighttime like conditions in the D region ionosphere and solar eclipse induced gravity waves coming to ionosphere from below and above. The present observations shed additional light on the current understanding of gravity waves induced D region ionospheric perturbations.

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“…Hines (1960), Hines (1974), Francis (1975), Richmond (1978), Hunsucker (1982) and most recently by Jing and Hunsucker (1993). In summary, three mechanisms which lead to the formation of an AGW in the auroral zone are (1) Joule heating (frictional heating of the neutral gas due to a di erence in velocity between the neutrals and the ions), (2) Lorentz momentum forcing (momentum transfer between the neutral gas and the ions due to collisions, synonymous with ion drag), and (3) heating due to particle precipitation.…”

Section: Introductionmentioning

confidence: 99%

A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere

Moffett

Millward

1997

Ann. Geophys.

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Abstract. First results of a modelling study of atmospheric gravity waves (AGWs) are presented. A fullycoupled global thermosphere-ionosphere-plasmasphere model is used to examine the relative importance of Lorentz forcing and Joule heating in the generation of AGWs. It is found that Joule heating is the dominant component above 110 km. The e ects of the direction of the Lorentz forcing component on the subsequent propagation of the AGW are also addressed. It is found that enhancement of zonal i Â f forcing results in AGWs at F-region altitudes of similar magnitudes travelling from the region of forcing in both poleward and equatorward directions, whilst enhancement of equatorward meridional i Â f forcing results in AGWs travelling both poleward and equatorward, but with the magnitude of the poleward wave severely attenuated compared with the equatorward wave.

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Atmospheric gravity waves generated in the high‐latitude ionosphere: A review

Cited by 648 publications

References 95 publications

Decameter mid-latitude sporadic-E irregularities in relation with gravity waves

Decameter mid-latitude sporadic-E irregularities in relation with gravity waves

Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

A study of the Joule and Lorentz inputs in the production of atmospheric gravity waves in the upper thermosphere

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