Application of tomographic inversion in studying airglow in the mesopause region

Nygrén, T.; Taylor, Michael J.; Lehtinen, M. S.; Markkanen, M.

doi:10.1007/s005850050687

Cited by 3 publications

(3 citation statements)

References 16 publications

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“…The first 3-D imaging has been done with ALIS data (e.g. Nygrén et al, 1998;Gustavsson et al, 2001) and by multi-spectral imaging from a single all-sky imager (Semeter et al, 2001). Soon auroral emission tomography will also be available using the THEMIS network of all-sky imagers.…”

Section: -D Ionospheric and Auroral Tomographymentioning

confidence: 99%

Towards understanding the electrodynamics of the 3-dimensional high-latitude ionosphere: present and future

Amm

Aruliah²,

Buchert

et al. 2008

Ann. Geophys.

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Abstract. Traditionally, due to observational constraints, ionospheric modelling and data analysis techniques have been devised either in one dimension (e.g. along a single radar beam), or in two dimensions (e.g. over a network of magnetometers). With new upcoming missions like the Swarm ionospheric multi-satellite project, or the EISCAT 3-D project, the time has come to take into account variations in all three dimensions simultaneously, as they occur in the real ionosphere. The link between ionospheric electrodynamics and the neutral atmosphere circulation which has gained increasing interest in the recent years also intrinsically requires a truly 3-dimensional (3-D) description. In this paper, we identify five major science questions that need to be addressed by 3-D ionospheric modelling and data analysis. We briefly review what proceedings in the young field of 3-D ionospheric electrodynamics have been made in the past to address these selected question, and we outline how these issues can be addressed in the future with additional observations and/or improved data analysis and simulation techniques. Throughout the paper, we limit the discussion to high-latitude and mesoscale ionospheric electrodynamics, and to directly data-driven (not statistical) data analysis.

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Section: -D Ionospheric and Auroral Tomographymentioning

confidence: 99%

Towards understanding the electrodynamics of the 3-dimensional high-latitude ionosphere: present and future

Amm

Aruliah²,

Buchert

et al. 2008

Ann. Geophys.

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“…Indirect manifestations of AGWs at ionospheric altitudes can be present in airglow and total electron content. In airglow images, AGWs can be visible as clear wavefronts [ Taylor et al , ; Nygrén et al , ; Nakamura et al , ; Gardner et al , ; Kubota et al , ; Pallamraju et al , ]. TID observations are made by various radar and tomographic methods.…”

Section: Introductionmentioning

confidence: 99%

Radar observations of simultaneous traveling ionospheric disturbances and atmospheric gravity waves

et al. 2015

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Simultaneous observations of atmospheric gravity waves (AGWs) and traveling ionospheric disturbances (TIDs) measured by an incoherent scatter radar at high latitudes are shown. The measurements were made using a beam swing experiment of the EISCAT UHF radar. The F region TID is seen as wavefronts in electron density, whereas the E region AGW is seen in the oscillations of the neutral wind. The wave vector of the TID has a downward component indicating that energy propagates upward. The periods of AGWs and TIDs are approximately the same (52–57min), so it is concluded that the observed gravity wave in the E region propagates to the F region causing the TID there. Two interesting properties of the waves are observed. First, the neutral wind oscillations have an amplitude minimum at about 115km. It is suggested that this could be related to the minimum of the vertical refractive index around 120km. Second, in the course of time, the wave vector of the TID turns more in the downward direction, which leads to an increase in the horizontal wave length from 400 to 1450km. A possible explanation is that the background wind increases with altitude and turns the wavefronts more horizontal when distance from a stationary source increases. We suggest that the source is the sunrise terminator, since the horizontal direction of propagation of the TID in the morning hours is from the west, where both the auroral and thunderstorm activity are low.

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“…Because of the large distance between the sites, reconstructions were obtained only from an area close to one of the sites. This stochastic inversion technique was later applied to 2D tomographic reconstructions of gravity wave structure in the hydroxyl (OH) airglow layer; the study was, however, limited to simulated reconstructions and a linear chain of five camera sites [23]. A subsequent airglow study compared the performance of a five-camera chain to a two-camera configuration with simulations, and also presented reconstructions from two-camera measurements of the OI (557.7 nm) emission layer from Hawaii [24].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional tomographic reconstruction of mesospheric airglow structures using two-station ground-based image measurements

et al. 2012

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A new methodology is presented to create two-dimensional (2D) and three-dimensional (3D) tomographic reconstructions of mesospheric airglow layer structure using two-station all-sky image measurements. A fanning technique is presented that produces a series of cross-sectional 2D reconstructions, which are combined to create a 3D mapping of the airglow volume. The imaging configuration is discussed and the inherent challenges of using limited-angle data in tomographic reconstructions have been analyzed using artificially generated imaging objects. An iterative reconstruction method, the partially constrained algebraic reconstruction technique (PCART), was used in conjunction with a priori information of the airglow emission profile to constrain the height of the imaged region, thereby reducing the indeterminacy of the inverse problem. Synthetic projection data were acquired from the imaging objects and the forward problem to validate the tomographic method and to demonstrate the ability of this technique to accurately reconstruct information using only two ground-based sites. Reconstructions of the OH airglow layer were created using data recorded by all-sky CCD cameras located at Bear Lake Observatory, Utah, and at Star Valley, Wyoming, with an optimal site separation of ∼100 km. The ability to extend powerful 2D and 3D tomographic methods to two-station ground-based measurements offers obvious practical advantages for new measurement programs. The importance and applications of mesospheric tomographic reconstructions in airglow studies, as well as the need for future measurements and continued development of techniques of this type, are discussed.

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Application of tomographic inversion in studying airglow in the mesopause region

Cited by 3 publications

References 16 publications

Towards understanding the electrodynamics of the 3-dimensional high-latitude ionosphere: present and future

Towards understanding the electrodynamics of the 3-dimensional high-latitude ionosphere: present and future

Radar observations of simultaneous traveling ionospheric disturbances and atmospheric gravity waves

Three-dimensional tomographic reconstruction of mesospheric airglow structures using two-station ground-based image measurements

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