Bibliography
|
Notice:
|
Found 43 entries in the Bibliography.
Showing entries from 1 through 43
| 2022 |
|
Low-latitude plasma blobs above Africa: Exploiting GOLD and multi-satellite in situ measurements Low-latitude plasma blobs are localized density enhancements of electron density that are occasionally observed in the night-time tropical ionosphere. Two-dimensional (2D) imaging of this phenomenon has been rare and frequently restricted to Central/South America, which is densely covered with ground-based airglow imagers and Global Navigation Satellite System (GNSS) receivers. In Africa, on the contrary, no 2D image of a blob has been reported. Here we present two low-latitude blob events above Africa, one in the Northern summer and the other in winter, in the 2-dimensional Far-UltraViolet (FUV) images from the Global-scale Observations of the Limb and Disk (GOLD) mission. Additionally, multiple satellites (four spacecraft per event) on the Low-Earth-Orbit (LEO) encountered the blob events, some within the GOLD images and some outside. The LEO data support the robustness of GOLD observations and bridge time gaps between the consecutive images. Properties of the two blob events above Africa generally support the conclusions in a previous case study for Central/South America. Plasma therein exhibited higher O+ fraction and faster ion flow toward outer L-shells than the ambient. The blobs were conjugate to locally intensified Equatorial Ionization Anomaly crests without conspicuous equatorward-westward propagation. Our results demonstrate the usefulness of GOLD and multiple LEO satellites in monitoring the ionosphere above Africa, which is a fascinating laboratory of low-latitude electrodynamics but still waiting for more observatories to be deployed. Park, Jaeheung; Min, Kyoung; Eastes, Richard; Chao, Chi; Kim, Hee-Eun; Lee, Junchan; Sohn, Jongdae; Ryu, Kwangsun; Seo, Hoonkyu; Yoo, Ji-Hyeon; Lee, Seunguk; Woo, Changho; Kim, Eo-Jin; Published by: Advances in Space Research Published on: may YEAR: 2022 DOI: 10.1016/j.asr.2022.05.021 |
| 2021 |
|
We use the \textlessi\textgreateram\textlessi/\textgreater, \textlessi\textgreateran, as\textlessi/\textgreater and the \textlessi\textgreateraσ\textlessi/\textgreater geomagnetic indices to the explore a previously overlooked factor in magnetospheric electrodynamics, namely the inductive effect of diurnal motions of the Earth’s magnetic poles toward and away from the Sun caused by Earth’s rotation. Because the offset of the (eccentric dipole) geomagnetic pole from the rotational axis is roughly twice as large in the southern hemisphere compared to the northern, the effects there are predicted to be roughly twice the amplitude of those in the northern hemisphere. Hemispheric differences have previously been discussed in terms of polar ionospheric conductivities generated by solar photoionization, effects which we allow for by looking at the dipole tilt effect on the time-of-year variations of the indices. The electric field induced in a geocentric frame is shown to also be a significant factor and gives a modulation of the voltage applied by the solar wind flow in the southern hemisphere that is typically a ±30\% diurnal modulation for disturbed intervals rising to ±76\% in quiet times. For the northern hemisphere these are 15\% and 38\% modulations. Motion away from/towards the Sun reduces/enhances the directly-driven ionospheric voltages and reduces/enhances the magnetic energy stored in the tail and we estimate that approximately 10\% of the effect appears in directly driven ionospheric voltages and 90\% in changes of the rate of energy storage or release in the near-Earth tail. The hemispheric asymmetry in the geomagnetic pole offsets from the rotational axis is shown to be the dominant factor in driving Universal Time (\textlessi\textgreaterUT\textlessi/\textgreater) variations and hemispheric differences in geomagnetic activity. Combined with the effect of solar wind dynamic pressure and dipole tilt on the pressure balance in the near-Earth tail, the effect provides an excellent explanation of how the observed Russell-McPherron pattern with time-of-year \textlessi\textgreaterF\textlessi/\textgreater and \textlessi\textgreaterUT\textlessi/\textgreater in the driving power input into the magnetosphere is converted into the equinoctial \textlessi\textgreaterF\textlessi/\textgreater-\textlessi\textgreaterUT\textlessi/\textgreater pattern in average geomagnetic activity (after correction is made for dipole tilt effects on ionospheric conductivity), added to a pronounced \textlessi\textgreaterUT\textlessi/\textgreater variation with minimum at 02–10 UT. In addition, we show that the predicted and observed \textlessi\textgreaterUT\textlessi/\textgreater variations in average geomagnetic activity has implications for the occurrence of the largest events that also show the nett \textlessi\textgreaterUT\textlessi/\textgreater variation. Lockwood, Mike; Haines, Carl; Barnard, Luke; Owens, Mathew; Scott, Chris; Chambodut, Aude; McWilliams, Kathryn; Published by: Journal of Space Weather and Space Climate Published on: YEAR: 2021 DOI: 10.1051/swsc/2020077 |
| 2019 |
|
Geocoronal hydrogen emission variation over two solar cycles Ground-based hydrogen Balmer-α observations from Northern midlatitudes span multiple solar cycles, facilitating investigation of decadal scale variations, including natural variability in the hydrogen response to solar geophysical changes. Here we present a reanalysis of ground-based hydrogen emission observations from the early 1990s and their comparison with observations obtained in 2000–2001 in the context of the extended Northern Hemisphere midlatitude geocoronal hydrogen emission data set. Nossal, SM; Mierkiewicz, EJ; Roesler, FL; Woodward, RC; Gardner, DD; Haffner, LM; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2019 DOI: 10.1029/2019JA026903 |
| 2017 |
|
The Global-Scale Observations of the Limb and Disk (GOLD) Mission The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understanding the global-scale response of the thermosphere-ionosphere (T-I) system to these drivers is essential to advancing our physical understanding of coupling between the space environment and the Earth\textquoterights atmosphere. Previous missions have successfully determined how the \textquotedblleftclimate\textquotedblright of the T-I system responds. The Global-scale Observations of the Limb and Disk (GOLD) mission will determine how the \textquotedblleftweather\textquotedblright of the T-I responds, taking the next step in understanding the coupling between the space environment and the Earth\textquoterights atmosphere. Operating in geostationary orbit, the GOLD imaging spectrograph will measure the Earth\textquoterights emissions from 132 to 162 nm. These measurements will be used image two critical variables\textemdashthermospheric temperature and composition, near 160 km\textemdashon the dayside disk at half-hour time scales. At night they will be used to image the evolution of the low latitude ionosphere in the same regions that were observed earlier during the day. Due to the geostationary orbit being used the mission observes the same hemisphere repeatedly, allowing the unambiguous separation of spatial and temporal variability over the Americas. Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.; Published by: Space Science Reviews Published on: 10/2017 YEAR: 2017 DOI: 10.1007/s11214-017-0392-2 |
|
The Relationship between Auroral Boundary Location and Geomagnetic Disturbance Intensity Woodroffe, Jesse; Morley, Steven; Dann, Julian; Published by: Published on: |
| 2016 |
|
Spectroscopic Exploration of Solar Flares Sibeck, DG; Paxton, LJ; Woods, TN; Published by: Published on: |
|
Mlynczak, Martin; , Russell; Hunt, Linda; Christensen, Andrew; Paxton, Larry; Woods, Thomas; Niciejewski, Richard; Yee, Jeng-Hwa; Published by: Published on: |
|
Spatial and Temporal Variability of Atomic Oxygen in The Mesosphere And Lower Thermosphere Yee, Jeng-Hwa; , Russell; Mlynczak, Martin; Christensen, Andrew; Paxton, Larry; Zhang, Yongliang; Skinner, Wilbert; Woods, Thomas; Published by: Published on: |
| 2015 |
|
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. This paper documents the extraction of these data products from the limb emission rates. We present the characteristics of the GUVI limb observations, retrievals of thermospheric neutral composition and temperature from the forward model, and the dramatic changes of the thermosphere with the solar cycle and geomagnetic activity. We examine the solar extreme ultraviolet (EUV) irradiance magnitude and trends through comparison with simultaneous Solar Extreme EUV (SEE) measurements on TIMED and find the EUV irradiance inferred from GUVI averaged (2002\textendash2007) 30\% lower magnitude than SEE version 11 and varied less with solar activity. The smaller GUVI variability is not consistent with the view that lower solar EUV radiation during the past solar minimum is the cause of historically low thermospheric mass densities. Thermospheric O and N2 densities are lower than the NRLMSISE-00 model, but O2 is consistent. We list some lessons learned from the GUVI program along with several unresolved issues. 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 |
|
Where does the Thermospheric Ionospheric GEospheric Research (TIGER) Program go? At the 10th Thermospheric Ionospheric GEospheric Research (TIGER/COSPAR) symposium held in Moscow in 2014 the achievements from the start of TIGER in 1998 were summarized. During that period, great progress was made in measuring, understanding, and modeling the highly variable UV-Soft X-ray (XUV) solar spectral irradiance (SSI), and its effects on the upper atmosphere. However, after more than 50years of work the radiometric accuracy of SSI observation is still an issue and requires further improvement. Based on the extreme ultraviolet (EUV) data from the SOLAR/SolACES, and SDO/EVE instruments, we present a combined data set for the spectral range from 16.5 to 105.5nm covering a period of 3.5years from 2011 through mid of 2014. This data set is used in ionospheric modeling of the global Total Electron Content (TEC), and in validating EUV SSI modeling. For further investigations the period of 3.5years is being extended to about 12years by including data from SOHO/SEM and TIMED/SEE instruments. Similarly, UV data are used in modeling activities. After summarizing the results, concepts are proposed for future real-time SSI measurements with in-flight calibration as experienced with the ISS SOLAR payload, for the development of a space weather camera for observing and investigating space weather phenomena in real-time, and for providing data sets for SSI and climate modeling. Other planned topics are the investigation of the relationship between solar EUV/UV and visible/near-infrared emissions, the impact of X-rays on the upper atmosphere, the development of solar EUV/UV indices for different applications, and establishing a shared TIGER data system for EUV/UV SSI data distribution and real-time streaming, also taking into account the achievements of the FP7 SOLID (First European SOLar Irradiance Data Exploitation) project. For further progress it is imperative that coordinating activities in this special field of solar–terrestrial relations and solar physics is emphasized. Schmidtke, G.; Avakyan, S.V.; Berdermann, J.; Bothmer, V.; Cessateur, G.; Ciraolo, L.; Didkovsky, L.; de Wit, Dudok; Eparvier, F.G.; Gottwald, A.; Haberreiter, M.; Hammer, R.; Jacobi, Ch.; Jakowski, N.; Kretzschmar, M.; Lilensten, J.; Pfeifer, M.; Radicella, S.M.; Schäfer, R.; Schmidt, W.; Solomon, S.C.; Thuillier, G.; Tobiska, W.K.; Wieman, S.; Woods, T.N.; Published by: Advances in Space Research Published on: YEAR: 2015 DOI: https://doi.org/10.1016/j.asr.2015.07.043 UV/EUV solar spectral irradiance; Instrumentation; Calibration; Modeling |
| 2014 |
|
Geomagnetic control of equatorial plasma bubble activity modeled by the TIEGCM with Kp Describing the day-to-day variability of Equatorial Plasma Bubble (EPB) occurrence remains a significant challenge. In this study we use the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIEGCM), driven by solar (F10.7) and geomagnetic (Kp) activity indices, to study daily variations of the linear Rayleigh-Taylor (R-T) instability growth rate in relation to the measured scintillation strength at five longitudinally distributed stations. For locations characterized by generally favorable conditions for EPB growth (i.e., within the scintillation season for that location), we find that the TIEGCM is capable of identifying days when EPB development, determined from the calculated R-T growth rate, is suppressed as a result of geomagnetic activity. Both observed and modeled upward plasma drifts indicate that the prereversal enhancement scales linearly with Kp from several hours prior, from which it is concluded that even small Kpchanges cause significant variations in daily EPB growth. Carter, B.; Retterer, J.; Yizengaw, E.; Groves, K.; Caton, R.; McNamara, L.; Bridgwood, C.; Francis, M.; Terkildsen, M.; Norman, R.; Zhang, K.; Published by: Geophysical Research Letters Published on: 08/2014 YEAR: 2014 DOI: 10.1002/2014GL060953 |
|
Summary of Research Report for TIMED Solar EUV Experiment (SEE) Published by: Published on: |
| 2012 |
|
The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth\textquoterights upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105\ nm with unprecedented spectral resolution (0.1\ nm), temporal cadence (ten seconds), and accuracy (20\%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37\ nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105\ nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39\ nm, and a MEGS-Photometer measures the Sun\textquoterights bright hydrogen emission at 121.6\ nm. The EVE data products include a near real-time space-weather product (Level\ 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15\ minutes. The EVE higher-level products are Level\ 2 with the solar EUV irradiance at higher time cadence (0.25\ seconds for photometers and ten seconds for spectrographs) and Level\ 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth\textquoterights ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team. Woods, T.; Eparvier, F.; Hock, R.; Jones, A.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.; McMullin, D.; Chamberlin, P.; Berthiaume, G.; Bailey, S.; Fuller-Rowell, T.; Sojka, J.; Tobiska, W.; Viereck, R.; Published by: Solar Physics Published on: 01/2012 YEAR: 2012 DOI: 10.1007/s11207-009-9487-6 |
|
The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth\textquoterights upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105\ nm with unprecedented spectral resolution (0.1\ nm), temporal cadence (ten seconds), and accuracy (20\%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37\ nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105\ nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39\ nm, and a MEGS-Photometer measures the Sun\textquoterights bright hydrogen emission at 121.6\ nm. The EVE data products include a near real-time space-weather product (Level\ 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15\ minutes. The EVE higher-level products are Level\ 2 with the solar EUV irradiance at higher time cadence (0.25\ seconds for photometers and ten seconds for spectrographs) and Level\ 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth\textquoterights ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team. Woods, T.; Eparvier, F.; Hock, R.; Jones, A.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.; McMullin, D.; Chamberlin, P.; Berthiaume, G.; Bailey, S.; Fuller-Rowell, T.; Sojka, J.; Tobiska, W.; Viereck, R.; Published by: Solar Physics Published on: 01/2012 YEAR: 2012 DOI: 10.1007/s11207-009-9487-6 |
| 2011 |
|
Solar extreme ultraviolet irradiance: Present, past, and future Lean, J.; Woods, T.; Eparvier, F.; Meier, R.; Strickland, D.; Correira, J.; Evans, J.; Published by: Journal of Geophysical Research Published on: Jan-01-2011 YEAR: 2011 DOI: 10.1029/2010JA015901 |
| 2010 |
|
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: |
| 2009 |
|
Woods, Thomas; Chamberlin, Phillip; Published by: Advances in Space Research Published on: Jan-02-2009 YEAR: 2009 DOI: 10.1016/j.asr.2008.10.027 |
|
Sun-to-Earth Imaging for Operational Space Weather Monitoring Chua, DH; Wood, BE; Slinker, SP; Meier, RR; Englert, CR; Socker, DG; Huba, J; Krall, J; Published by: Published on: |
|
Continuous FUV/EUV Imaging of the Ionosphere from Geosynchronous Orbit Wood, Kent; Dymond, KF; Budzien, SA; McDonald, SE; Coker, C; Nicholas, AC; Kowalski, MP; Published by: To use new imaging systems to generate measurements in 2-dimensional formats continuously for large regions with high spatial resolution Published on: |
| 2008 |
|
Photoelectron flux variations observed from the FAST satellite This paper examines high resolution (ΔE/E\ =\ 0.15) photoelectron energy spectra from 10\ eV to 1\ keV, created by solar irradiances between 1.2 and 120\ nm. The observations were made from the FAST satellite at \~3000\ km, equatorward of the auroral oval for the July\textendashAugust, 2002 solar rotation. These data are compared with the solar irradiance observed by the Solar EUV Experiment (SEE) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and fluxes calculated using the Field Line Interhemispheric Plasma (FLIP) code. The 41\ eV photoelectron flux, which corresponds to solar EUV fluxes near 20\ nm, shows a clear solar rotation variation in very good agreement with the EUV flux measurements. This offers the possibility that the 41\ eV photoelectron flux could be used as a check on measured solar EUV fluxes near 20\ nm. Because of unexpected noise, the solar rotation signal is not evident in the integral photoelectron flux between 156 and 1000\ eV corresponding to EUV wavelengths between 0.1 and 7\ nm measured by the SEE instrument. Examination of daily averaged photoelectron fluxes at energies between 25 and 500\ eV show significant changes in the photoelectron spectra in response X and M class flares. The intensity of photoelectrons produced in this energy region is primarily due to two very narrow EUV wavelength regions at 2.3 and 3\ nm driving Auger photoionization in O at 500\ eV and N2\ at \~360\ eV. Comparison of calculated and daily averaged electron fluxes shows that the HEUVAC model solar spectrum used in the FLIP code does not reproduce the observed variations in photoelectron intensity. In principle, the 21 discrete photoelectron energy channels could be used to improve the reliability of the solar EUV fluxes at 2.3 and 3\ nm inferred from broad band observations. In practice, orbital biases in the way the data were accumulated and/or noise signals arising from natural and anthropogenic longitudinally restricted sources of ionization complicate the application of this technique. Peterson, W.K.; Woods, T.N.; Chamberlin, P.C.; Richards, P.G.; Published by: Advances in Space Research Published on: Jan-09-2008 YEAR: 2008 DOI: 10.1016/j.asr.2007.08.038 |
|
XUV Photometer System (XPS): Improved Solar Irradiance Algorithm Using CHIANTI Spectral Models Woods, Thomas; Chamberlin, Phillip; Peterson, W.; Meier, R.; Richards, Phil; Strickland, Douglas; Lu, Gang; Qian, Liying; Solomon, Stanley; Iijima, B.; Mannucci, A.; Tsurutani, B.; Published by: Solar Physics Published on: Jan-08-2008 YEAR: 2008 DOI: 10.1007/s11207-008-9196-6 |
| 2007 |
|
Strickland, D.; Lean, J.; Daniell, R.; Knight, H.; Woo, W.; Meier, R.; Straus, P.; Woods, T.; Eparvier, F.; McMullin, D.; Christensen, A.; Morrison, D.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2007 YEAR: 2007 DOI: 10.1029/2006JA012074 |
|
Strickland, D.; Lean, J.; Daniell, R.; Knight, H.; Woo, W.; Meier, R.; Straus, P.; Woods, T.; Eparvier, F.; McMullin, D.; Christensen, A.; Morrison, D.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2007 YEAR: 2007 DOI: 10.1029/2006JA012074 |
|
Kozyra, JU; Crowley, G; Doe, RA; Mlynczak, MG; Paxton, LJ; Skinner, WR; Solomon, SC; Talaat, E; Woods, TN; Wu, Q; , others; Published by: Published on: |
|
Strickland, DJ; Lean, JL; , Daniell; Knight, HK; Woo, WK; Meier, RR; Straus, PR; Woods, TN; Eparvier, FG; McMullin, DR; , others; Published by: Journal of Geophysical Research: Space Physics Published on: |
|
Strickland, DJ; Lean, JL; , Daniell; Knight, HK; Woo, WK; Meier, RR; Straus, PR; Woods, TN; Eparvier, FG; McMullin, DR; , others; Published by: Journal of Geophysical Research: Space Physics Published on: |
| 2006 |
|
The TIGER (thermospheric\textendashionospheric geospheric research) program: Introduction Schmidtke, G.; Eparvier, F.G.; Solomon, S.C.; Tobiska, W.K.; Woods, T.N.; Published by: Advances in Space Research Published on: Jan-01-2006 YEAR: 2006 DOI: 10.1016/j.asr.2005.02.088 |
| 2005 |
|
Some of the most intense solar flares measured in 0.1 to 0.8 nm x-rays in recent history occurred near the end of 2003. The Nov 4 event is the largest in the NOAA records (X28) and the Oct 28 flare was the fourth most intense (X17). The Oct 29 flare was class X7. These flares are compared and contrasted to the July 14, 2000 Bastille Day (X10) event using the SOHO SEM 26.0 to 34.0 nm EUV and TIMED SEE 0.1\textendash194 nm data. High time resolution, \~30s ground-base GPS data and the GUVI FUV dayglow data are used to examine the flare-ionosphere relationship. In the 26.0 to 34.0 nm wavelength range, the Oct 28 flare is found to have a peak intensity greater than twice that of the Nov 4 flare, indicating strong spectral variability from flare-to-flare. Solar absorption of the EUV portion of the Nov 4 limb event is a possible cause. The dayside ionosphere responds dramatically (\~2.5 min 1/e rise time) to the x-ray and EUV input by an abrupt increase in total electron content (TEC). The Oct 28 TEC ionospheric peak enhancement at the subsolar point is \~25 TECU (25 \texttimes 1012 electrons/cm2) or 30\% above background. In comparison, the Nov 4, Oct 29 and the Bastille Day events have \~5\textendash7 TECU peak enhancements above background. The Oct 28 TEC enhancement lasts \~3 hrs, far longer than the flare duration. This latter ionospheric feature is consistent with increased electron production in the middle altitude ionosphere, where recombination rates are low. It is the EUV portion of the flare spectrum that is responsible for photoionization of this region. Further modeling will be necessary to fully understand the detailed physics and chemistry of flare-ionosphere coupling. Tsurutani, B.; Judge, D.; Guarnieri, F.; Gangopadhyay, P.; Jones, A.; Nuttall, J.; Zambon, G.A.; Didkovsky, L.; Mannucci, A.J.; Iijima, B.; Meier, R.; Immel, T.J.; Woods, T.; Prasad, S.; Floyd, L.; Huba, J.; Solomon, S.; Straus, P.; Viereck, R.; Published by: Geophysical Research Letters Published on: 02/2005 YEAR: 2005 DOI: 10.1029/2004GL021475 |
|
Yee, J; Christensen, A; Russell, J; Killeen, T; Woods, T; Kozyra, J; Smith, A; Fritts, D; Forbes, J; Mayr, H; , others; Published by: Published on: |
|
Solar EUV Experiment (SEE): Mission overview and first results [1]\ The Solar EUV Experiment (SEE) is one of four scientific instruments on the NASA Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) spacecraft, which has been simultaneously observing the Sun and Earth\textquoterights upper atmosphere since January 2002. The SEE instrument measures the irradiance of the highly variable, solar extreme ultraviolet (EUV) radiation, one of the major energy sources for the upper atmosphere. The primary SEE data product is the solar spectral irradiances from 0.1 to 194 nm in 1 nm intervals that are fundamental for the TIMED mission\textquoterights investigation of the energetics in the tenuous, but highly variable, layers of the Earth\textquoterights atmosphere above 60 km. The TIMED mission began normal operations on 22 January 2002, a time when the Sun displayed maximum levels of activity for solar cycle 23, and has provided daily measurements as solar activity has declined to moderate levels. Solar irradiance variability observed by SEE during the 2 years of the TIMED prime mission includes a variety of moderate and large flares over periods of seconds to hours and dozens of solar rotational cycles over a typical period of 27 days. The SEE flare measurements provide important, new results because of the simultaneous spectral coverage from 0.1 to 194 nm, albeit limited temporal coverage due to its 3\% duty cycle. In addition, the SEE measurements reveal important, new results concerning phase shifts of 2\textendash7 days in the intermediate-term variations between different UV wavelengths that appear to be related to their different center-to-limb variations. The new solar EUV irradiance time series from SEE are also important in filling the \textquotedblleftEUV Hole,\textquotedblright which is the gap in irradiance measurements in the EUV spectrum since the 1980s. The solar irradiances measured by SEE (Version 7, released July 2004) are compared with other measurements and predictions from models of the solar EUV irradiance. While the measurement comparisons show reasonable agreement, there are significant differences between SEE and some of the models in the EUV range. The data processing algorithms and calibrations are also discussed. Woods, Thomas; Eparvier, Francis; Bailey, Scott; Chamberlin, Phillip; Lean, Judith; Rottman, Gary; Solomon, Stanley; Tobiska, Kent; Woodraska, Donald; Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012) Published on: YEAR: 2005 DOI: 10.1029/2004JA010765 thermosphere; solar activity cycle; solar irradiance; ultraviolet emissions; solar effects |
|
Solar EUV Experiment (SEE): Mission overview and first results [1]\ The Solar EUV Experiment (SEE) is one of four scientific instruments on the NASA Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) spacecraft, which has been simultaneously observing the Sun and Earth\textquoterights upper atmosphere since January 2002. The SEE instrument measures the irradiance of the highly variable, solar extreme ultraviolet (EUV) radiation, one of the major energy sources for the upper atmosphere. The primary SEE data product is the solar spectral irradiances from 0.1 to 194 nm in 1 nm intervals that are fundamental for the TIMED mission\textquoterights investigation of the energetics in the tenuous, but highly variable, layers of the Earth\textquoterights atmosphere above 60 km. The TIMED mission began normal operations on 22 January 2002, a time when the Sun displayed maximum levels of activity for solar cycle 23, and has provided daily measurements as solar activity has declined to moderate levels. Solar irradiance variability observed by SEE during the 2 years of the TIMED prime mission includes a variety of moderate and large flares over periods of seconds to hours and dozens of solar rotational cycles over a typical period of 27 days. The SEE flare measurements provide important, new results because of the simultaneous spectral coverage from 0.1 to 194 nm, albeit limited temporal coverage due to its 3\% duty cycle. In addition, the SEE measurements reveal important, new results concerning phase shifts of 2\textendash7 days in the intermediate-term variations between different UV wavelengths that appear to be related to their different center-to-limb variations. The new solar EUV irradiance time series from SEE are also important in filling the \textquotedblleftEUV Hole,\textquotedblright which is the gap in irradiance measurements in the EUV spectrum since the 1980s. The solar irradiances measured by SEE (Version 7, released July 2004) are compared with other measurements and predictions from models of the solar EUV irradiance. While the measurement comparisons show reasonable agreement, there are significant differences between SEE and some of the models in the EUV range. The data processing algorithms and calibrations are also discussed. Woods, Thomas; Eparvier, Francis; Bailey, Scott; Chamberlin, Phillip; Lean, Judith; Rottman, Gary; Solomon, Stanley; Tobiska, Kent; Woodraska, Donald; Published by: Journal of Geophysical Research: Space Physics (1978\textendash2012) Published on: YEAR: 2005 DOI: 10.1029/2004JA010765 thermosphere; solar activity cycle; solar irradiance; ultraviolet emissions; solar effects |
|
Tsurutani, BT; Judge, DL; Meier, RR; Immel, TJ; Woods, TN; Published by: Geophysical research letters Published on: |
| 2004 |
|
TIMED GUVI and SEE Observations of Solar Irradiance Variations and the Terrestrial Airglow Response Wolven, B; Paxton, L; Morrison, D; Woods, T; Published by: Published on: |
|
Solar irradiance variability during the October 2003 solar storm period Woods, Thomas; Eparvier, Francis; Fontenla, Juan; Harder, Jerald; Kopp, Greg; McClintock, William; Rottman, Gary; Smiley, Byron; Snow, Martin; Published by: Geophysical research letters Published on: |
| 2003 |
|
Yee, Jeng-Hwa; Talaat, Elsayed; Christensen, Andrew; Killeen, Timothy; Russell, James; Woods, Thomas; Published by: Johns Hopkins APL Technical Digest Published on: |
|
Talaat, Elsayed; Yee, Jeng-Hwa; Christensen, Andrew; Killeen, Timothy; Russell, James; Woods, Thomas; Published by: Johns Hopkins APL technical digest Published on: |
|
Solomon, SC; Bailey, SM; Eparvier, FG; Gladstone, GR; Paxton, LJ; Woods, TN; Published by: Published on: |
|
Lean, JL; Strickland, DJ; Meier, RR; Christensen, AB; Woods, TN; Eparvier, FG; McMullin, D; Judge, DL; Published by: Published on: |
| 2002 |
|
Solomon, SC; Bailey, SM; Christensen, AB; Eparvier, FG; Gladstone, GR; Paxton, LJ; Wolven, BC; Woods, TN; Published by: Published on: |
|
Weiss, MB; Paxton, LJ; Barnes, RJ; Eichert, JJ; Wood, WC; Morrison, D; Christensen, AB; Strickland, DJ; Craven, JD; Meier, RR; , others; Published by: Published on: |
|
Imaging Space Weather in the Far Ultraviolet with NASA TIMED GUVI Paxton, L; Morrison, D; Zhang, Y; Kil, H; Wolven, B; Humm, D; Ogorzalek, B; Weiss, M; Wood, W; Barnes, R; , others; Published by: Published on: |
|
Energy Balance in the Sun-Earth System During the Solar Storm Events of April 2002 Mlynczak, MG; Paxton, L; Kozyra, J; Woods, T; Zurbuchen, T; Lu, G; Lopez-Puertas, M; Martin-Torres, FJ; RUSSELL, JM; Crowley, G; , others; Published by: Published on: |
|
Paxton, L; Morrison, D; Zhang, Y; Kil, H; Wolven, B; Humm, D; Ogorzalek, B; Weiss, M; Wood, W; Barnes, R; , others; Published by: Published on: |
1