A self‐consistent model of helium in the thermosphere

Sutton, E. K.; Thayer, J. P.; Wang, Wenbin; Solomon, Stanley C.; Liu, Xianjing; Foster, B.

doi:10.1002/2015ja021223

Cited by 36 publications

(58 citation statements)

References 67 publications

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“…TIE‐GCM v.2.0 includes the following new physical features (Maute, ; Qian et al, ): 2.5° horizontal resolution is supported, electrodynamo calculations are parallelized, helium is calculated as a major species (Sutton et al, ), argon is calculated as a minor species, the geomagnetic field is updated to the International Geomagnetic Reference Field version 12, and its annual secular variation is included for the years 1900–2020.…”

Section: Model and Data Descriptionsmentioning

confidence: 99%

“…The tidal forcing at the height of the lower boundary (~97 km) is specified by Global Scale Wave Model diurnal and semidiurnal migrating and nonmigrating tidal amplitudes and phases (Hagan & Forbes, 2003). TIE-GCM v.2.0 includes the following new physical features (Maute, 2017;Qian et al, 2014): 2.5°horizontal resolution is supported, electrodynamo calculations are parallelized, helium is calculated as a major species (Sutton et al, 2015), argon is calculated as a minor species, the geomagnetic field is updated to the Journal of Geophysical Research: Space Physics…”

Section: Tie-gcm V20mentioning

confidence: 99%

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First Results From the Ionospheric Extension of WACCM‐X During the Deep Solar Minimum Year of 2008

Liu

Wang

et al. 2018

JGR Space Physics

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New ionosphere and electrodynamics modules have been incorporated in the thermosphere and ionosphere eXtension of the Whole Atmosphere Community Climate Model (WACCM‐X), in order to self‐consistently simulate the coupled atmosphere‐ionosphere system. The first specified dynamics WACCM‐X v.2.0 results are compared with several data sets, and with the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIE‐GCM), during the deep solar minimum year. Comparisons with Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite of temperature and zonal wind in the lower thermosphere show that WACCM‐X reproduces the seasonal variability of tides remarkably well, including the migrating diurnal and semidiurnal components and the nonmigrating diurnal eastward propagating zonal wavenumber 3 component. There is overall agreement between WACCM‐X, TIE‐GCM, and vertical drifts observed by the Communication/Navigation Outage Forecast System (C/NOFS) satellite over the magnetic equator, but apparent discrepancies also exist. Both model results are dominated by diurnal variations, while C/NOFS observed vertical plasma drifts exhibit strong temporal variations. The climatological features of ionospheric peak densities and heights (NmF2 and hmF2) from WACCM‐X are in general agreement with the results derived from Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) data, although the WACCM‐X predicted NmF2 values are smaller, and the equatorial ionization anomaly crests are closer to the magnetic equator compared to COSMIC and ionosonde observations. This may result from the excessive mixing in the lower thermosphere due to the gravity wave parameterization. These data‐model comparisons demonstrate that WACCM‐X can capture the dynamic behavior of the coupled atmosphere and ionosphere in a climatological sense.

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Section: Model and Data Descriptionsmentioning

confidence: 99%

Section: Tie-gcm V20mentioning

confidence: 99%

First Results From the Ionospheric Extension of WACCM‐X During the Deep Solar Minimum Year of 2008

Liu

Wang

et al. 2018

JGR Space Physics

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“…Equation and the differential form of the species continuity equation [ Sutton et al , , equations (A8) and (A13)] are very closely related. For instance, equation can be directly obtained from the appropriate triple‐integration of Sutton et al's equation (A8).…”

Section: Mass Conservation Equationmentioning

confidence: 99%

“…Even with the log pressure vertical coordinate, tracking the transport of a minor species is not a straightforward task using a differential equation for species continuity. In particular, a difficulty arises during the derivation of such an equation, as is evident in Sutton et al [2015]: The steps between their equations (A8) and (A13) eliminate divergence terms from the species continuity equation using the continuity equation of the total gas. This simplifies the equation, while rendering implicit the fact that for any amount of a species entering (exiting) an infinitesimal volume due to horizontal convergence (divergence), the exact same amount also exits (enters) due to vertical divergence (convergence).…”

Section: Mass Conservation Equationmentioning

confidence: 99%

Interhemispheric transport of light neutral species in the thermosphere

Sutton

2016

Geophysical Research Letters

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A mechanistic description of neutral species transport is presented, reconciling two long‐standing yet ostensibly incompatible interpretations of the “wind‐induced diffusion” of thermospheric constituents. Regarding the creation and sustainment of anomalous winter distributions of light species (e.g., atomic oxygen or helium), the theory of Reber and Hays (1973) cites vertical advection as the main cause while Mayr et al. (1978) cite horizontal transport—both in the presence of a diffusively separated atmosphere. We demonstrate that these theories are not at odds with each other. Instead, they describe two coherent aspects of a single process: convergent (divergent) horizontal motion increases downwelling (upwelling), thereby transporting light constituents both horizontally and vertically simultaneously. Such a connection between horizontal and vertical transport is straightforward and well established for the mass‐averaged circulation. Yet this connection has remained obscure for a single minor species entrained within the flow, in part due to the appearance of the composition equation when expressed in a Eulerian frame of reference. Concrete evidence is presented in terms of model equations and diagnostics, establishing a direct link between the horizontal and vertical transport of an atmospheric constituent. Consequently, we are able to show that winter accumulations of light species arise from an interhemispheric migration operating on seasonal timescales, rather than from their redistribution within the vertical column. This new understanding has implications for the timescales at play in both the F region ionosphere and lower exosphere, two regions profoundly impacted by light neutral species.

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“…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 (Sutton et al [72]). …”

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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A self‐consistent model of helium in the thermosphere

Cited by 36 publications

References 67 publications

First Results From the Ionospheric Extension of WACCM‐X During the Deep Solar Minimum Year of 2008

First Results From the Ionospheric Extension of WACCM‐X During the Deep Solar Minimum Year of 2008

Interhemispheric transport of light neutral species in the thermosphere

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

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