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Found 24 entries in the Bibliography.
Showing entries from 1 through 24
| 2021 |
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We describe a long-term data set of global average thermospheric mass density derived from orbit data on ∼7,700 objects in low Earth orbit, via the effect of atmospheric drag. The data cover the years 1967–2019 and altitudes 250–575 km, and the temporal resolution is 3–4 days for most years. The data set is an extension and revision of a previous version. The most important change is the use of more precise orbit data: special perturbation state vectors are now used starting in 2001, instead of mean Keplerian orbital ... Emmert, J.; Dhadly, M.; Segerman, A.; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2021 DOI: 10.1029/2021JA029455 |
| 2020 |
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A 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 c ... Weimer, D.; Mehta, P.; Tobiska, W.; Doornbos, E.; Mlynczak, M.; Drob, D.; Emmert, J.; Published by: Space Weather Published on: 12/2019 YEAR: 2020 DOI: 10.1029/2019SW002355 |
| 2018 |
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How might the thermosphere and ionosphere react to an extreme space weather event? This chapter explores how the thermosphere and ionosphere (T-I) might respond to extreme solar events. Three different scenarios are considered: (1) an increase in solar UV and EUV radiation for a number of days, (2) an extreme enhancement in the solar X-rays and EUV radiation associated with a flare, and (3) an extreme CME driving a geomagnetic storm. Estimating the response to the first two scenarios is reasonably well defined, and although they would certainly impact the T-I system, those impacts could potentially be miti ... Fuller-Rowell, Tim; Emmert, John; Fedrizzi, Mariangel; Weimer, Daniel; Codrescu, Mihail; Pilinski, Marcin; Sutton, Eric; Viereck, Rodney; Raeder, Joachim; Doornbos, Eelco; Published by: Published on: YEAR: 2018 DOI: 10.1016/B978-0-12-812700-1.00021-2 |
| 2015 |
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Thermospheric mass density: A review The mass density of Earth\textquoterights thermosphere (\~90\textendash600\ km altitude) is a critical parameter for low Earth orbit prediction because of the atmospheric drag on satellites in this region. In this review, we first survey techniques for measuring thermospheric density, empirical models that provide a synthesis of historical data, and physical models that simulate the environment by solving fluid equations. We then review the climate and weather features that are observed in thermospheric density (incl ... Published by: Advances in Space Research Published on: 09/2015 YEAR: 2015 DOI: 10.1016/j.asr.2015.05.038 |
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Remote sensing of Earth's limb by TIMED/GUVI: Retrieval of thermospheric composition and temperature The Global Ultraviolet Imager (GUVI) onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite senses far ultraviolet emissions from O and N2 in the thermosphere. Transformation of far ultraviolet radiances measured on the Earth limb into O, N2, and O2 number densities and temperature quantifies these responses and demonstrates the value of simultaneous altitude and geographic information. Composition and temperature variations are available from 2002 to 2007 ... Meier, R.; Picone, J.; Drob, D.; Bishop, J.; Emmert, J.; Lean, J.; Stephan, A.; Strickland, D.; Christensen, A.; Paxton, L.; Morrison, D.; Kil, H.; Wolven, B.; Woods, Thomas; Crowley, G.; Gibson, S.; Published by: Earth and Space Science Published on: 01/2015 YEAR: 2015 DOI: 10.1002/2014EA000035 airglow and aurora; remote sensing; thermosphere: composition and chemistry; thermosphere: energy deposition |
| 2014 |
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Attribution of interminima changes in the global thermosphere and ionosphere We present a statistical attribution analysis of the changes in global annual average thermospheric mass density and ionospheric total electron content (TEC) between the cycle 22/23 solar minimum (which occurred at epoch 1996.4) and the prolonged cycle 23/24 minimum (2008.8). The mass density data are derived from orbital drag, and the TEC data are derived from ground-based GPS receivers. The interminima change in mass density was -36\% relative to the 1996.4 yearly average. Considering each multiplicative forcing indepen ... Emmert, J.; McDonald, S.; Drob, D.; Meier, R.; Lean, J.; Picone, J.; Published by: Journal of Geophysical Research: Space Physics Published on: 08/2014 YEAR: 2014 DOI: 10.1002/2013JA019484 ionosphere total electron content; solar minimum; thermosphere mass density |
| 2013 |
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Theoretical tools for studies of low-frequency thermospheric variability [1]\ This paper supports studies of low-frequency variability (LFV) within the thermosphere by deriving approximate integral and closed-form solutions of a nontrivial model of thermospheric temperature, density, and composition depending on altitude and time. We also provide a paradigm for applying dimensional analysis in such studies. The domain is the region between the mesopause and the exobase. The solutions emphasize the connectedness of the thermosphere, i.e., nonlocal influences of LFV in key physical paramete ... Picone, J.; Meier, R.; Emmert, J.; Published by: Journal of Geophysical Research: Space Physics Published on: 09/2013 YEAR: 2013 DOI: 10.1002/jgra.v118.910.1002/jgra.50472 dimensional analysis; low frequency variation; Pi Theorem; seasonal variation; semi-annual variation; thermospheric variability |
| 2012 |
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SAMI3 Simulations of Ionospheric Variability from 1996 to 2011
McDonald, SE; Lean, J; Huba, JD; Emmert, JT; Drob, DP; Siefring, CL; Meier, RR; Picone, J; Published by: Published on: |
| 2011 |
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Global and regional trends in ionospheric total electron content
Lean, J.; Emmert, J.; Picone, J.; Meier, R.; Published by: Journal of Geophysical Research Published on: Jan-01-2011 YEAR: 2011 DOI: 10.1029/2010JA016378 |
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Ionospheric total electron content: Global and hemispheric climatology
Lean, J.; Meier, R.; Picone, J.; Emmert, J.; Published by: Journal of Geophysical Research Published on: Jan-01-2011 YEAR: 2011 DOI: 10.1029/2011JA016567 |
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A study of space shuttle plumes in the lower thermosphere
Meier, R.; Stevens, Michael; Plane, John; Emmert, J.; Crowley, G.; Azeem, I.; Paxton, L.; Christensen, A.; Published by: Journal of Geophysical Research Published on: Jan-01-2011 YEAR: 2011 DOI: 10.1029/2011JA016987 |
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Simulating Ionospheric Variability in the Descending Phase of Solar Cycle-23 using SAMI3
McDonald, SE; Lean, J; Huba, JD; Joyce, GR; Emmert, JT; Drob, DP; Stephan, AW; Siefring, CL; Meier, RR; Picone, J; Published by: Published on: |
| 2010 |
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Record-low thermospheric density during the 2008 solar minimum
Emmert, J.; Lean, J.; Picone, J.; Published by: Geophysical Research Letters Published on: Jan-06-2010 YEAR: 2010 DOI: 10.1029/2010GL043671 |
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Dynamical Properties of Shuttle Plumes in the Lower Thermosphere
Meier, RR; Stevens, MH; Plane, JM; Emmert, JT; Crowley, G; Paxton, LJ; Christensen, AB; Azeem, SI; Published by: Published on: |
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Integrating the Sun-Earth System for the Operational Environment (ISES-OE)
Lean, J.; Huba, J.; McDonald, S.; Slinker, S.; Drob, D.; Emmert, J.; Meier, R.; Picone, J.; Joyce, G.; Krall, J.; Stephan, A.; Roach, K.; Knight, H.; Plunkett, S.; Wu, C.-C.; Wood, B.; Wang, Y.-M.; Howard, R.; Chen, J.; Bernhardt, P.; Fedder, J.; Published by: Published on: |
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Stevens, MH; Meier, RR; Plane, JM; Emmert, JT; Russell, J; Published by: Published on: |
| 2008 |
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We use orbit data on ∼5000 near-Earth space objects to investigate long-term trends in thermospheric total mass density, which has been predicted to decrease with time due to increasing CO2 concentrations. We refine and extend to 2007 previous density trend estimates, and investigate solar cycle-dependent bias in empirical density models previously used to filter out solar irradiance effects. We find that the bias is caused in part by the solar cycle dependence of the long-term trends, and we develop a new representation ... Emmert, JT; Picone, IM; Meier, RR; Published by: Geophysical Research Letters Published on: YEAR: 2008 DOI: 10.1029/2007GL032809 |
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Long-term climatology and trends of global average thermospheric density
Emmert, John; Picone, Michael; Meier, Robert; Published by: 37th COSPAR Scientific Assembly Published on: |
| 2006 |
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Thermospheric densities derived from spacecraft orbits: Application to the Starshine satellites
Lean, J.; Picone, J.; Emmert, J.; Moore, G.; Published by: Journal of Geophysical Research Published on: Jan-01-2006 YEAR: 2006 DOI: 10.1029/2005JA011399 |
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Emmert, JT; Meier, RR; Picone, JM; Lean, JL; Christensen, AB; Published by: Journal of Geophysical Research Published on: YEAR: 2006 DOI: 10.1029/2005JA011495 |
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Thermospheric density 2002–2004: TIMED/GUVI dayside limb observations and satellite drag We use TIMED/GUVI dayside limb observations of thermospheric far ultraviolet (FUV) dayglow to infer height profiles of total mass density during the period 2002–2004. We compare these data with total mass density derived from drag-induced changes in the orbits of satellites with perigee heights ranging from 200 to 600 km. To accommodate sampling differences, we compute the ratio of observed total mass density, filtered on a 3-day timescale, to that predicted by the NRLMSISE-00 empirical model. The GUVI densities are in goo ... Emmert, JT; Meier, RR; Picone, JM; Lean, JL; Christensen, AB; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2006 DOI: https://doi.org/10.1029/2005JA011495 |
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Thermospheric density 2002—2004: TIMED/GUVI dayside limb observations and satellite drag
Emmert, JT; Meier, RR; Picone, JM; Lean, JL; Christensen, AB; Published by: Journal of Geophysical Research: Space Physics Published on: |
| 2005 |
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Emmert, JT; Meier, RR; Picone, JM; Lean, JL; Published by: Published on: |
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SSUSI and GUVI limb scans of thermospheric neutral density changes during a geomagnetic storm
Stephan, AW; Picone, JM; Meier, RR; Emmert, JT; Paxton, LJ; Morrison, D; Wolven, B; Kil, H; Published by: Published on: |
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