Bibliography
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Found 7 entries in the Bibliography.
Showing entries from 1 through 7
| 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 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. 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 mitigated. In contrast, the response to an extreme geomagnetic storm is significantly more complicated, making the response much more uncertain, and mitigation more challenging. 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 |
| 2012 |
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Burns, A.G.; Solomon, S.C.; Qian, L.; Wang, W.; Emery, B.A.; Wiltberger, M.; Weimer, D.R.; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: Jan-07-2012 YEAR: 2012 DOI: 10.1016/j.jastp.2012.02.006 |
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Anomalously low geomagnetic energy inputs during 2008 solar minimum Deng, Yue; Huang, Yanshi; Solomon, Stan; Qian, Liying; Knipp, Delores; Weimer, Daniel; Wang, Jing-Song; Published by: Journal of Geophysical Research Published on: Jan-01-2012 YEAR: 2012 DOI: 10.1029/2012JA018039 |
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Solomon, Stanley; Burns, Alan; Emery, Barbara; Mlynczak, Martin; Qian, Liying; Wang, Wenbin; Weimer, Daniel; Wiltberger, Michael; Published by: Journal of Geophysical Research Published on: Jan-01-2012 YEAR: 2012 DOI: 10.1029/2011JA017417 |
| 2010 |
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Comparison of the Hill\textendashSiscoe polar cap potential theory with the Weimer and AMIE models Kelley, Michael; Crowley, Geoffrey; Weimer, Daniel; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: Jan-03-2010 YEAR: 2010 DOI: 10.1016/j.jastp.2009.02.011 |
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Comparison of the Hill–Siscoe polar cap potential theory with the Weimer and AMIE models The magnetic storm on November 2004 was characterized by a high solar wind pressure and thus offers a unique opportunity to test the Hill–Siscoe formula (H–S) for the polar cap potential (PCP). To estimate the polar cap potential, we use the Weimer Statistical Convection Model (WCM), and the Assimilative Mapping of Ionospheric Electrodynamics Model (AMIE), based on ingestion of a number of data sets. H–S is in excellent agreement with WCM, and with AMIE during times when DMSP is used in the latter. The implication is that the AMIE conductivity model yields conductivities that are too high by a factor of 2–3. Both H–S and WCM display saturation effects, although WCM is more severe. The two methods track well until an IEF of about 20mV/m occurs, where H–S continues to increase while WCM levels off. Even at high electric field values, the pressure increases the denominator of the H–S formula by 60\%, keeping the potential lower than its saturation value. There are several H–S points above 250kV, even up to 400kV, that are not found in WCM and occur right after a rapid transition from Bz north to south. For Bz north, we find evidence for a saturation effect on the PCP at large IEF, little effect as a function of solar wind velocity, and an increase of the PCP with increasing pressure. This seems to rule out viscous interaction but may involve geometric changes in the high-altitude polar cusp that affect recombination there for Bz north. Kelley, Michael; Crowley, Geoffrey; Weimer, Daniel; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: YEAR: 2010 DOI: https://doi.org/10.1016/j.jastp.2009.02.011 Magnetic storm; Polar cap potential; Hill–Siscoe formula; solar wind |
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