Horizontal distribution of helium in the Earth's upper atmosphere

Reber, C. A.; Harpold, D. N.; Horowitz, Richard; Hedin, A. E.

doi:10.1029/ja076i007p01845

Cited by 42 publications

(21 citation statements)

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“…Other ionic constituents such as He + and N § exist in the topside ionosphere, but they are usually minor constituents (Hoffman, 1967;Brinton et aI., 1969). The values of neutral hydrogen adopted by these authors are smaller by about an order or so than those obtained by Reber et al (1968) from direct measurements with satellite and by Brinton et al (1969) from measurements of ion composition in the F-region. Protons in the protonosphere are supplied by upward diffusion from the region of proton source by the reaction (18) during the day, and lost by downward diffusion to the region of proton sink by the reaction (18) in a reverse direction at night.…”

Section: Winter ~ Summercontrasting

confidence: 54%

Theoretical models of ionospheric storms

Matuura¹

1972

Space Sci Rev

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Section: Winter ~ Summercontrasting

confidence: 54%

Theoretical models of ionospheric storms

Matuura¹

1972

Space Sci Rev

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“…Global properties in the distribution of composition and temperature, inferred from these measurements, were reported by Reber et al (1971), Taeusch et al (1971), , Carignan and Reber (1971), Hedin et al ( , 1973aHedin et al ( , 1973b), .…”

Section: Empirical Modelmentioning

confidence: 90%

Global characteristics in the diurnal variations of the thermospheric temperature and composition

Mayr¹,

Hedin²,

Reber³

et al. 1974

J. Geophys. Res.

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Global characteristics in the diurnal components of Ogo 6 neutral mass spectrometer measurements near 450 km are discussed qualitatively as well as quantitatively on the basis of a theoretical model. Observations and conclusions are summarized: (1) during equinox the temperature maximum occurs after 1600 LT at the equator and shifts toward 1500 LT at the poles, whereas the oxygen concentration at 450 km peaks about 1 h earlier (this observed phase difference is attributed primarily to wind‐induced diffusion, which is most effective for the mass density near 250 km and thus can contribute considerably to the temperature‐density phase anomaly in the thermosphere); (2) there is general agreement between the magnitudes and the phases of the diurnal, semidiurnal, and terdiurnal temperature components at 450 km from theory as well as from Ogo 6 and radar backscatter measurements; (3) the maximum in the diurnal variation of He is observed near 1030 LT consistent with theoretical results that further emphasize the importance of dynamics and diffusion; (4) during solstice conditions the diurnal temperature maximum shifts toward later local times in substantial agreement with radar temperature measurements; and (5) the temperature‐oxygen density phase difference at 450 km is observed to decrease with latitude from the winter toward the summer hemisphere, where oxygen may even peak after the temperature at high latitudes. This effect is attributed to the diurnal variation in the O2 dissociation, which becomes most significant in the summer hemisphere, where the dissociation rate is enhanced and where the atomic oxygen abundance in the lower thermosphere is significantly reduced, owing to the annual component in the large‐scale circulation.

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“…New ratios in excess of an order of magnitude could then be obtained through this method as well. In addition to establishing a larger bulge ratio, Reber et al [55] noted a strong correlation of the maximum helium density with the location of the winter geomagnetic pole. This was interpreted as a sensitivity of the helium distribution to the thermospheric wind system.…”

Section: Introductionmentioning

confidence: 99%

“…Reber et al [55], using mass spectrometer measurements from the Ogo 6 satellite, showed an order-of-magnitude difference between the helium content in winter and summer hemispheres near 400-600 km altitude. This disagreement with previous results highlighted the limitations of the drag-inferred technique, specifically, reliance on the assumption of diffusive equilibrium to separate composition-induced mass density variations from those caused by temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Hodges [19] modeled large-scale fluctuations as monochromatic plane waves, which effected a downward transport and an overall decrease to the scale height of species with masses smaller than the mean mass. Similarly, Kockarts [30] derived the eddy diffusivity profile necessary to reconstruct the winter helium bulge observations of Reber et al [55], under the assumption of molecular diffusion in the absence of wind. Results from these studies suggested that eddy diffusion could in fact control the global helium distribution.…”

Section: Introductionmentioning

confidence: 99%

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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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Horizontal distribution of helium in the Earth's upper atmosphere

Cited by 42 publications

References 4 publications

Theoretical models of ionospheric storms

Theoretical models of ionospheric storms

Global characteristics in the diurnal variations of the thermospheric temperature and composition

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

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