Phase and amplitude relationships of wave structure observed in the lower thermosphere

Reber, C. A.; Hedin, A. E.; Pelz, D. T.; Potter, W. E.; Brace, L. H.

doi:10.1029/ja080i034p04576

Cited by 55 publications

(35 citation statements)

References 20 publications

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“…Considering the global geometry as well as the dissipative and diffusive properties of the thermosphere, numerical models such as those of Richmond and Matsushita (1975), Richmond (1978aRichmond ( , b, 1979, Roble et al (1978) and are required to describe gravity waves as they are excited by auroral sources.…”

Section: Introductionmentioning

confidence: 99%

“…A major theoretical effort on gravity waves was undertaken by Richmond and Matsushita (1975) and Richmond (1978aRichmond ( , b, 1979 who developed realistic numerical models for a spherical Earth to describe the substorm response of the thermosphere driven by auroral zone currents, ion drift momentum coupling and precipitating particles. Their analysis showed that disturbances generated by such sources propagate equatorward with a speed of about 750 m s -l, the temperature and wind perturbations decaying slowly before reaching the equator.…”

Section: Introductionmentioning

confidence: 99%

“…Partial reflection from the dissipative medium at high altitudes (Yanowitch, 1967a(Yanowitch, , b, 1969 and from the lower thermosphere (Richmond, 1978a), and total reflection from the Earth's surface (Francis, 1974) may be important. Hines (1960) and Friedman (1966) suggested that the lower atmosphere behaves like an imperfect duct from which gravity waves can leak into the thermosphere.…”

Section: Introductionmentioning

confidence: 99%

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Thermospheric gravity waves: Observations and interpretation using the transfer function model (TFM)

et al. 1990

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Gravity waves are prominent in the polar region of the terrestiral thermosphere, and can be excited by perturbations in Joule heating and Lorents force due to magnetospheric processes. We show observations from the Dynamics Explorer-2 satellite to illustrate the complexity of the phenomenon and review the transfer function model (TFM) which has guided our interpretation. On a statistical basis, the observed atmospheric perturbations decrease from the poles toward the equator and tend to correlate with the magnetic activity index, Ap. although individual measurements indicate that the magnetic index is often a poor measure of gravity wave excitation. The theoretical models devised to describe gravity waves are multifaceted. On one end are fully analytical, linear models which are based on the work of Hines. On the other end are fully numerical, thermospheric general circulation models (TGCMs) which incorporate non-linear processes and wave mean flow interactions. The transfer function model (TFM) discussed in this paper is between these two approaches. It is less restrictive than the analytical approach and relates the gIobal propagation of gravity waves to their excitation. Compared with TGCMs, the TFM is simplified by its linear approximation; but it is not limited in spatial and temporal resolution, and the TFM describes the wave propagation through the lower atmosphere. Moreover, the TFM is semianalytical which helps in delineating the wave components. Using expansions in terms of spherical harmonics and Fourier components, the transfer function is obtained from numerical height integration. This is time consuming computationally but needs to be done only once. Once such a transfer function is computed, the wave response to arbitrary source distributions on the globe can then be constructed in very short order. In this review, we discuss some numerical experiments performed with the TFM, to study the various wave components excited in the auroral regions which propagate through the thermosphere and lower atmosphere, and to elucidate the properties of realistic source geometries. The model is applied to the interpretation of satellite measurements. Gravity waves observed in the thermosphere of Venus are also discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermospheric gravity waves: Observations and interpretation using the transfer function model (TFM)

et al. 1990

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“…, 1961). The picture of neutral waves that emerges from integrating theory and observation (Newton et al, 1969, Reber et al , 1975 Meriwether et al , 1973, Brekke et al , 1974 can Dopp ler sh ift neutral waves to frequencie s between -0 and twice their natural frequency.…”

Section: Atmospheric Waves As Source Of Loss Cone Variationsmentioning

confidence: 99%

Auroral pulsations from atmospheric waves

Luhmann¹

1979

J. Geophys. Res.

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A mechanism for producing quasi‐periodic fluctuations in the intensity of auroral light is proposed in which pressure waves in the neutral atmosphere drive the pulsations. A model is constructed to describe how a horizontal movement of the atmosphere can cause the energy deposition by a steady particle distribution to vary with time if the isodensity surfaces of the local atmosphere become nonplanar. When the distortions are wavelike corrugations and the horizontal motion is steady and also has a component normal to the phase front, periodic variations in auroral brightness can result. The pulse shape and the magnitude of the pulsations depend on both the energy spectrum and the pitch angle distribution of the particles and the amplitude and altitude distribution of the atmospheric waves. It is suggested that the required atmospheric oscillations can be provided by acoustic‐gravity waves which are generated by active arcs near the poleward edge of the auroral oval. This mechanism can also produce aperiodic pulsations by convection of irregular atmospheric density fluctuations, some of which may result from interfering acoustic‐gravity wave trains.

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“…The open source mass spectrometers on Atmospheric Explorer satellites (AE-C, -D, and -E) were used by several investigators to further quantify seasonal variations [40,41,2]. Reber et al [57] also analyzed these data to study waves in composition, showing coherent phase relationships between the various constituents. Hedin and Carignan [15] used data from the Dynamics Explorer 2 (DE-2) satellite to show that even during geomagnetically quiet times, signatures of helium depletion are present near the magnetic poles.…”

Section: Introductionmentioning

confidence: 99%

Semi-Empirical, First-Principles, and Hybrid Modeling of the Thermosphere to Enhance Data Assimilation

Sutton¹

2015

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)27-10-2015 (From -To) REPORT TYPE Final Report DATES COVERED AFRL-RV-PS-TR-2015-0168 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)AFRL/RVBXI SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. (OPS-15-9186 dtd 17 Nov 2015) SUPPLEMENTARY NOTES ABSTRACTDuring this task, we established a method for extracting the most significant basis functions from a physics-based model of the thermosphere and ionosphere. A new model was then constructed by replacing the spherical harmonic functions used in an existing semiempirical thermosphere model with these basis functions. The resulting hybrid model, published in the Space Weather Journal, demonstrated the ability to represent sparse thermospheric data in a more accurate and efficient way. In addition, we chose Jacchia 1970 as our underlying semi-empirical model so that the new hybrid model functions as a direct replacement for the High Accuracy Satellite Drag Model used by AFSPC and the JSpOC. We also worked to improve the hybrid model by investigating the limitations of and possible improvements to the underlying assumptions imposed by the chosen models. In particular, we realized that there was a large and potentially significant component missing from all general circulation models, that being the appropriate treatment of helium in the upper thermosphere. To rectify this situation, we undertook the project of adding helium to the solution of a first-principles community model of the thermosphere and ionosphere. In doing this, we discovered that this could only be done self-consistently by solving for helium as a major species, as opposed to as a minor species. The product of this work was the first physics-based model to accurately simulate the seasonal and latitudinal behavior of the helium distribution. This work was published in the Journal of Geophysical Research. 64This page is intentionally left blank.Approved for public release; distribution is unlimited.

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Phase and amplitude relationships of wave structure observed in the lower thermosphere

Cited by 55 publications

References 20 publications

Thermospheric gravity waves: Observations and interpretation using the transfer function model (TFM)

Thermospheric gravity waves: Observations and interpretation using the transfer function model (TFM)

Auroral pulsations from atmospheric waves

Semi-Empirical, First-Principles, and Hybrid Modeling of the Thermosphere to Enhance Data Assimilation

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