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dc.contributor.authorSiskind, David E.en
dc.contributor.authorJones, McArthur, Jr.en
dc.contributor.authorDrob, Douglas P.en
dc.contributor.authorMcCormack, John P.en
dc.contributor.authorHervig, Mark E.en
dc.contributor.authorMarsh, Daniel R.en
dc.contributor.authorMlynczak, Martin G.en
dc.contributor.authorBailey, Scott M.en
dc.contributor.authorMaute, Astriden
dc.contributor.authorMitchell, Nicholas J.en
dc.date.accessioned2019-10-17T13:36:29Z
dc.date.available2019-10-17T13:36:29Z
dc.date.issued2019-01-25en
dc.identifier.issn0992-7689en
dc.identifier.urihttp://hdl.handle.net/10919/94613
dc.description.abstractWe use data from two NASA satellites, the Thermosphere Ionosphere Energetics and Dynamics (TIMED) and the Aeronomy of Ice in the Mesosphere (AIM) satellites, in conjunction with model simulations from the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) to elucidate the key dynamical and chemical factors governing the abundance and diurnal variation of lower thermospheric nitric oxide (NO) at near-solar minimum conditions and low latitudes. This analysis was enabled by the recent orbital precession of the AIM satellite which caused the solar occultation pattern measured by the Solar Occultation for Ice Experiment (SOFIE) to migrate down to low and mid-latitudes for specific periods of time. We use a month of NO data collected in January 2017 to compare with two versions of the TIME-GCM; one is driven solely by climatological tides and analysis-derived planetary waves at the lower boundary and is free running at all other altitudes, and the other is constrained by a high-altitude analysis from the Navy Global Environmental Model (NAVGEM) up to the mesopause. We also compare SOFIE data with a NO climatology from the nitric oxide empirical model (NOEM). Both SOFIE and NOEM yield peak NO abundances of around 4 x 10(7) cm(-3); however, the SOFIE profile peaks about 6-8 km lower than NOEM. We show that this difference is likely a local time effect, with SOFIE being a dawn measurement and NOEM representing late morning and/or near noon. The constrained version of TIME-GCM exhibits a low-altitude dawn peak, while the model that is forced solely at the lower boundary and free running above does not. We attribute this difference to a phase change in the semi-diurnal tide in the NAVGEM-constrained model, causing the descent of high NO mixing ratio air near dawn. This phase difference between the two models arises due to differences in the mesospheric zonal mean zonal winds. Regarding the absolute NO abundance, all versions of the TIME-GCM overestimate this. Tuning the model to yield calculated atomic oxygen in agreement with TIMED data helps but is insufficient. Furthermore, the TIME-GCM underestimates the electron density (Ne) as compared with the International Reference Ionosphere (IRI) empirical model. This suggests a potential conflict with the requirements of NO modeling and Ne modeling, since one solution typically used to increase model Ne is to increase the solar soft X-ray flux, which would, in this case, worsen the NO model-data discrepancy.en
dc.description.sponsorshipNASA AIM Small Explorer program [S50029G]; NASA/TIMED SABER project [NNG17PX04I]; Office of Naval Research BSION program [N0001417WX00579]; NASA Heliophysics Supporting Research (HSR) program [NNH17AE69I]; NRL Karle Fellowship; NASANational Aeronautics & Space Administration (NASA) [X13AF77G, NNX16AG64G, NNH13AV95I]; National Science FoundationNational Science Foundation (NSF)en
dc.format.mimetypeapplication/pdfen
dc.language.isoenen
dc.publisherEuropean Geosciences Unionen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleOn the relative roles of dynamics and chemistry governing the abundance and diurnal variation of low-latitude thermospheric nitric oxideen
dc.typeArticle - Refereeden
dc.description.notesWe acknowledge support from the NASA AIM Small Explorer program (through the Interagency Purchase Request S50029G to NRL), the NASA/TIMED SABER project (through Interagency Purchase Request NNG17PX04I to NRL) and the Office of Naval Research BSION program, award number N0001417WX00579. Additionally, Douglas P. Drob acknowledges support from the NASA Heliophysics Supporting Research (HSR) program through interagency agreement NNH17AE69I to NRL. This work was performed while McArthur Jones Jr. held an NRL Karle Fellowship. John P. McCormack acknowledges support from NASA grant NNH13AV95I. Astrid Maute is supported by NASA grants X13AF77G and NNX16AG64G. Computational resources for this work were provided by the U.S. Department of Defense (Dod) High Performance Computing Modernization Program (HPCMP). We thank Stan Solomon of the High Altitude Observatory (HAO) for helpful discussion concerning nitric oxide chemistry and the internal reviewer at HAO for useful comments. NCAR is supported by the National Science Foundation.en
dc.title.serialAnnales Geophysicaeen
dc.identifier.doihttps://doi.org/10.5194/angeo-37-37-2019en
dc.identifier.volume37en
dc.identifier.issue1en
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen
dc.identifier.eissn1432-0576en


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