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Improving Neutral Density Predictions Using Exospheric Temperatures Calculated on a Geodesic, Polyhedral Grid

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dc.contributor.authorWeimer, Daniel R.en
dc.contributor.authorMehta, P. M.en
dc.contributor.authorTobiska, W. K.en
dc.contributor.authorDoornbos, E.en
dc.contributor.authorMlynczak, M. G.en
dc.contributor.authorDrob, Douglas P.en
dc.contributor.authorEmmert, J. T.en
dc.contributor.departmentCenter for Space Science and Engineering Researchen
dc.date.accessioned2021-01-13T16:01:18Zen
dc.date.available2021-01-13T16:01:18Zen
dc.date.issued2019-12-10en
dc.description.abstractA new model of exospheric temperatures has been developed, with the objective of predicting global values with greater spatial and temporal accuracy. From these temperatures, the neutral densities in the thermosphere can be calculated, through use of the Naval Research Laboratory Mass Spectrometer and Incoherent Scatter radar Extended (NRLMSISE-00) model. The exospheric temperature model is derived from measurements of the neutral densities on several satellites. These data were sorted into triangular cells on a geodesic grid, based on location. Prediction equations are derived for each grid cell using least error fits. Several versions of the model equations have been tested, using parameters such as the date, time, solar radiation, and nitric oxide emissions, as measured with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. Accuracy is improved with the addition of the total Poynting flux flowing into the polar regions, from an empirical model that uses the solar wind velocity and interplanetary magnetic field. Given such inputs, the model can produce global maps of the exospheric temperature. These maps show variations in the polar regions that are strongly modulated by the time of day, due to the daily rotation of the magnetic poles. For convenience the new model is referred to with the acronym EXTEMPLAR (EXospheric TEMperatures on a PoLyhedrAl gRid). Neutral densities computed from the EXTEMPLAR-NRLMSISE-00 models combined are found to produce very good results when compared with measured values.en
dc.description.notesDaniel Weimer was supported by NASA Grant NNX17AC04G to Virginia Tech, with additional support from a subcontract to Hampton University, on NASA Grant NNX15AE05G. M. G. M. acknowledges support from the NASA Heliophysics Division Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics Project. D. P. D and J. T. E. acknowledge support from the Office of Naval Research. The CHAMP and GRACE neutral density data are available online (at http://tinyurl.com/RSM-Models).The density measurements from Swarm, the L2 DNSxPOD data product, can be obtained online (through the website https://swarm-diss.eo.esa.int/#swarm%2FLevel2daily%2FLatest_baselines%2FDNS%2FPOD).The code for the NRLMSISE-00 neutral density model is available from the NASA CCMC (at https://ccmc.gsfc.nasa.gov/pub/modelweb/atmospheric/msis/nrlmsise00/).The SABER measurements of global power from carbon dioxide and nitric oxide are available at the SABER website (ftp://saber.gats-inc.com/Version2_0/SABER_cooling/). Linda Hunt generated the SABER NO data and provided manuscript corrections. The solar F10.7 and AP indices were obtained from the CelesTrak website (http://celestrak.com/SpaceData/SW-All.txt).The level 2 ACE data can be obtained from the NASA archives (at ftp://cdaweb.gsfc.nasa.gov/pub/data/ace). The solar indices (found at http://sol.spacenvironment.net/JB2008/indices) are provided by Space Environment Technologies. A data archive containing the supplemental graphs of neutral density predictions can be accessed online (at https://doi.org/10.5281/zenodo.3525166).Also contained here are the adjustments to the NRLMSISE-00 model supplied by J. Emmert; the total Poynting flux into both Northern and Southern Hemispheres from theWeimer 2005 model, for years 2002-2017; the derived.T values; and EXTEMPLAR model code with the required files.en
dc.description.sponsorshipNASANational Aeronautics & Space Administration (NASA) [NNX17AC04G, NNX15AE05G]; Office of Naval ResearchOffice of Naval Research; NASA Heliophysics Division Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics Projecten
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1029/2019SW002355en
dc.identifier.eissn1542-7390en
dc.identifier.issue1en
dc.identifier.othere2019SW002355en
dc.identifier.urihttp://hdl.handle.net/10919/101873en
dc.identifier.volume18en
dc.language.isoenen
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivs 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/en
dc.titleImproving Neutral Density Predictions Using Exospheric Temperatures Calculated on a Geodesic, Polyhedral Griden
dc.title.serialSpace Weather-The International Journal of Research And Applicationsen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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