Bibliography
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Found 10 entries in the Bibliography.
Showing entries from 1 through 10
| 2021 |
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The Wind Imaging Interferometer (WINDII) Empirical Model, which provides the characteristics of the O(1D) 630.0 nm atomic oxygen dayglow emission from the upper atmosphere has been reviewed and updated. It now includes the Integrated Emission Rate, the peak Volume Emission Rate, the Altitude of that peak and the Full Width at Half Maximum as functions of the F10.7 cm Solar Radio Flux and the solar zenith angle (SZA). The model employs 98,617 WINDII observations obtained between the years 1992 and 1996, and the model and observations of the Integrated Emission Rate agree well with one another within 2 standard deviations of 588.7 Rayleigh (R) (106 photons cm−2 sec−1). It is also demonstrated that the impact of latitude, longitude and day of year, independently of their contribution to the SZA, is very small. The WINDII Empirical Model is also shown to agree with results from the TRANSCAR photochemical model. The dayglow is challenging to measure with ground-based instruments, as the solar scattered light from the daytime sky must be accurately subtracted from the data. Ground-based measurements of the integrated emission rate have been made by others, with good agreement for observations from Hyderabad during the 2015 summer and winter, but mixed agreement with measurements made over Boston in 2003. The latter results are reviewed and assessed. Shepherd, Gordon; Cho, Young-Min; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028715 dayglow; empirical model; O(1D) Emission; solar radio flux; solar zenith angle; upper atmosphere |
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explanation, that the lower summer measurements were the result of atmospheric composition change, based on the change of [O/N2] observed during the Boston summer by the GUVI Shepherd, Gordon; Cho, Young-Min; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2020JA028715 |
| 2019 |
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Review of the accomplishments of mid-latitude Super Dual Auroral Radar Network (SuperDARN) HF radars The Super Dual Auroral Radar Network (SuperDARN) is a network of high-frequency (HF) radars located in the high- and mid-latitude regions of both hemispheres that is operated under international cooperation. The network was originally designed for monitoring the dynamics of the ionosphere and upper atmosphere in the high-latitude regions. However, over the last approximately 15 years, SuperDARN has expanded into the mid-latitude regions. With radar coverage that now extends continuously from auroral to sub-auroral and mid-latitudes, a wide variety of new scientific findings have been obtained. In this paper, the background of mid-latitude SuperDARN is presented at first. Then, the accomplishments made with mid-latitude SuperDARN radars are reviewed in five specified scientific and technical areas: convection, ionospheric irregularities, HF propagation analysis, ion-neutral interactions, and magnetohydrodynamic (MHD) waves. Finally, the present status of mid-latitude SuperDARN is updated and directions for future research are discussed. Nishitani, Nozomu; Ruohoniemi, John; Lester, Mark; Baker, Joseph; Koustov, Alexandre; Shepherd, Simon; Chisham, Gareth; Hori, Tomoaki; Thomas, Evan; Makarevich, Roman; , others; Published by: Progress in Earth and Planetary Science Published on: YEAR: 2019 DOI: 10.1186/s40645-019-0270-5 |
| 2018 |
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High-Latitude Observations of a Localized Wind Wall and Its Coupling to the Lower Thermosphere Reversals in the thermospheric zonal winds at altitudes of 140 to 250\ km from eastward to westward have been found at southern geographic latitudes between 60\textdegree and 70\textdegree. These are confined to a narrow region between 100\textdegree and 200\textdegree in longitude with zonal velocities regularly of -400\ m/s, sometimes reaching -600\ m/s, so sharply defined that the authors describe it as a \textquotedblleftwind wall.\textquotedblright The observations were made by the Wind Imaging Interferometer on National Aeronautics and Space Administration\textquoterights Upper Atmosphere Research Satellite, and they occur as the field of view crosses the high polar cap wind field. The wind reversals at the wall boundaries create a convergence on the west side of the wall and a divergence on the east side that potentially generate vertical flows, consistent with observed perturbations in the O(1S) emission rate. They are present about one half of the time in local summer and autumn. Shepherd, Gordon; Shepherd, Marianna; Published by: Geophysical Research Letters Published on: 05/2018 YEAR: 2018 DOI: 10.1029/2018GL077722 |
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High-Latitude Observations of a Localized Wind Wall and Its Coupling to the Lower Thermosphere Reversals in the thermospheric zonal winds at altitudes of 140 to 250\ km from eastward to westward have been found at southern geographic latitudes between 60\textdegree and 70\textdegree. These are confined to a narrow region between 100\textdegree and 200\textdegree in longitude with zonal velocities regularly of -400\ m/s, sometimes reaching -600\ m/s, so sharply defined that the authors describe it as a \textquotedblleftwind wall.\textquotedblright The observations were made by the Wind Imaging Interferometer on National Aeronautics and Space Administration\textquoterights Upper Atmosphere Research Satellite, and they occur as the field of view crosses the high polar cap wind field. The wind reversals at the wall boundaries create a convergence on the west side of the wall and a divergence on the east side that potentially generate vertical flows, consistent with observed perturbations in the O(1S) emission rate. They are present about one half of the time in local summer and autumn. Shepherd, Gordon; Shepherd, Marianna; Published by: Geophysical Research Letters Published on: 05/2018 YEAR: 2018 DOI: 10.1029/2018GL077722 |
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Longitudinal and seasonal variations of O (1D) nightglow emission maxima at southern midlatitudes Initial observations with the global ultraviolet imager (GUVI) in the NASA TIMED satellite and mass density observed with WINDII, GUVI, GOCE and simulated by NRLMSISE-00 Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: YEAR: 2018 DOI: 10.1016/j.jastp.2017.11.012 |
| 2017 |
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Shepherd, Gordon; Cho, Young-Min; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 01/2017 YEAR: 2017 DOI: 10.1016/j.jastp.2017.07.016 |
| 2016 |
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Shepherd, Gordon; Cho, Young-Min; Fomichev, Victor; Martynenko, Oleg; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: |
| 2012 |
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The Wind Imaging Interferometer (WINDII) was launched on the NASA\textquoterights Upper Atmosphere Research Satellite on 12 September 1991 and operated until 2003. Its role in the mission was to measure vector winds in the Earth\textquoterights atmosphere from 80 to 110 km, but its measurements extended to nearly 300 km. The approach employed was to measure Doppler shifts from a suite of visible region airglow lines emitted over this altitude range. These included atomic oxygen O(1S) and O(1D) lines, as well as lines in the OH Meinel (8,3) and O2 Atmospheric (0,0) bands. The instrument employed was a Doppler Michelson Interferometer that measured the Doppler shift as a phase shift of the cosinusoidal interferogram generated by single airglow lines. An extensive validation program was conducted after launch to confirm the accuracy of the measurements. The dominant wind field, the first one observed by WINDII, was that of the migrating diurnal tide at the equator. The overall most notable WINDII contribution followed from this: determining the influence of dynamics on the transport of atmospheric species. Currently, nonmigrating tides are being studied in the thermosphere at both equatorial and high latitudes. Other aspects investigated included solar and geomagnetic influences, temperatures from atmospheric-scale heights, nitric oxide concentrations, and the occurrence of polar mesospheric clouds. The results of these observations are reviewed from a perspective of 20 years. A future perspective is then projected, involving more recently developed concepts. It is intended that this description will be helpful for those planning future missions. Shepherd, G.; Thuillier, G.; Cho, Y.-M.; Duboin, M.-L.; Evans, W.; Gault, W.; Hersom, C.; Kendall, D.; Lathuillère, C.; Lowe, R.; McDade, I.; Rochon, Y.; Shepherd, M.; Solheim, B.; Wang, D.-Y.; Ward, W.; Published by: Reviews of Geophysics Published on: 06/2012 YEAR: 2012 DOI: 10.1029/2012RG000390 airglow; dynamics; interferometers; mesosphere; temperature; winds |
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The Wind Imaging Interferometer (WINDII) was launched on the NASA\textquoterights Upper Atmosphere Research Satellite on 12 September 1991 and operated until 2003. Its role in the mission was to measure vector winds in the Earth\textquoterights atmosphere from 80 to 110 km, but its measurements extended to nearly 300 km. The approach employed was to measure Doppler shifts from a suite of visible region airglow lines emitted over this altitude range. These included atomic oxygen O(1S) and O(1D) lines, as well as lines in the OH Meinel (8,3) and O2 Atmospheric (0,0) bands. The instrument employed was a Doppler Michelson Interferometer that measured the Doppler shift as a phase shift of the cosinusoidal interferogram generated by single airglow lines. An extensive validation program was conducted after launch to confirm the accuracy of the measurements. The dominant wind field, the first one observed by WINDII, was that of the migrating diurnal tide at the equator. The overall most notable WINDII contribution followed from this: determining the influence of dynamics on the transport of atmospheric species. Currently, nonmigrating tides are being studied in the thermosphere at both equatorial and high latitudes. Other aspects investigated included solar and geomagnetic influences, temperatures from atmospheric-scale heights, nitric oxide concentrations, and the occurrence of polar mesospheric clouds. The results of these observations are reviewed from a perspective of 20 years. A future perspective is then projected, involving more recently developed concepts. It is intended that this description will be helpful for those planning future missions. Shepherd, G.; Thuillier, G.; Cho, Y.-M.; Duboin, M.-L.; Evans, W.; Gault, W.; Hersom, C.; Kendall, D.; Lathuillère, C.; Lowe, R.; McDade, I.; Rochon, Y.; Shepherd, M.; Solheim, B.; Wang, D.-Y.; Ward, W.; Published by: Reviews of Geophysics Published on: 06/2012 YEAR: 2012 DOI: 10.1029/2012RG000390 airglow; dynamics; interferometers; mesosphere; temperature; winds |
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