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Found 25 entries in the Bibliography.
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2022 |
Total Electron Content Variations during an HSS/CIR driven storm at high and middle latitudes Geethakumari, Gopika; Aikio, Anita; Cai, Lei; Vanhamaki, Heikki; Pedersen, Marcus; Coster, Anthea; Marchaudon, Aurélie; Blelly, Pierre-Louis; Haberle, Veronika; Maute, Astrid; Ellahouny, Nada; Virtanen, Ilkka; Norberg, Johannes; Soyama, Shin-Ichiro; Grandin, Maxime; Published by: Published on: mar YEAR: 2022   DOI: 10.5194/egusphere-egu22-8194 |
Low-latitude plasma blobs have been studied since their first being reported in 1986. However, investigations on temporal evolution of a blob or on continental scale (\textgreater2,000 km) ionospheric contexts around it are relatively rare. Overcoming these limitations can help elucidate the blob generation mechanisms. On 21 January 2021, the Ionospheric Connection Explorer satellite encountered a typical low-latitude blob near the northeastern coast of South America. The event was collocated with a local enhancement in 135.6 nm nightglow at the poleward edge of an equatorial plasma bubble (EPB), as observed by the Global-scale Observations of the Limb and Disk (GOLD) imager. Total electron content maps from the Global Navigation Satellite System confirm the GOLD observations. Unlike typical medium-scale traveling ionospheric disturbances (MSTIDs), the blob had neither well-organized wavefronts nor moved in the southwest direction. Neither was the blob a monotonically decaying equatorial ionization anomaly crest past sunset. Rather, the blob varied following latitudinal expansion/contraction of EPBs at similar magnetic longitudes. The observational results support that mechanisms other than MSTIDs, such as EPBs, can also contribute to blob generation. Park, Jaeheung; Huang, Chao-Song; Eastes, Richard; Coster, Anthea; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022   DOI: 10.1029/2021JA029992 |
Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere-thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global-scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption-induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14–17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X-pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long-lasting quasi-periodic fluctuations between ±200 m/s for 7–8 hr after the passage of volcano-induced Lamb waves. The EIA suppression and X-pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal. Aa, Ercha; Zhang, Shun-Rong; Wang, Wenbin; Erickson, Philip; Qian, Liying; Eastes, Richard; Harding, Brian; Immel, Thomas; Karan, Deepak; Daniell, Robert; Coster, Anthea; Goncharenko, Larisa; Vierinen, Juha; Cai, Xuguang; Spicher, Andres; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022   DOI: 10.1029/2022JA030527 EIA suppression and X-pattern; Equatorial ionization anomaly; GNSS TEC; GOLD UV images; ICON MIGHTI neutral wind; Tonga volcano eruption |
A plasma density hole was created in the ionosphere by a rocket launch from Cape Canaveral, Florida near local sunset on 30 August 2020, which is called rocket exhaust depletion (RED). The hole persisted for several hours into the night and was observed in total electron content (TEC) maps, the Global-scale Observations of the Limb and Disk (GOLD) imager, and multiple low-earth-orbit satellites. The RED created a nightglow pit in the GOLD 135.6 nm image. Swarm satellites found that the RED exhibited insignificant changes in electron/ion temperature and field-aligned currents. On the other hand, magnetic field strength was enhanced inside the RED by a few tenths of a nanotesla. Assimilation data products of the Constellation Observing System for Meteorology, Ionosphere, and Climate 2 (COSMIC-2) mission reveal that ionospheric slab thickness increased at the center of the RED, which is supported by combined analyses of the GOLD and TEC data. The RED did not host conspicuous substructures that are stronger and longer-lasting than the ambient plasma did. Park, Jaeheung; Rajesh, P.; Ivarsen, Magnus; Lin, Charles; Eastes, Richard; Chao, Chi; Coster, Anthea; Clausen, Lasse; Burchill, Johnathan; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2022   DOI: 10.1029/2021JA029909 GOLD; Madrigal TEC; COSMIC-2; Norsat-1; rocket exhaust depletion; swarm |
2021 |
Goncharenko, Larisa; Harvey, Lynn; Greer, Katelynn; Zhang, Shun-Rong; Coster, Anthea; Paxton, Larry; Published by: Geophysical Research Letters Published on: |
2020 |
Comparison of GOLD nighttime measurements with total electron content: Preliminary results The National Aeronautics and Space Administration (NASA) Global‐scale Observations of the Limb and Disk (GOLD) has been imaging the thermosphere and ionosphere since Cai, Xuguang; Burns, Alan; Wang, Wenbin; Coster, Anthea; Qian, Liying; Liu, Jing; Solomon, Stanley; Eastes, Richard; Daniell, Robert; McClintock, William; Published by: Journal of Geophysical Research: Space Physics Published on: YEAR: 2020   DOI: 10.1029/2019JA027767 |
2017 |
The main focus of this dissertation is the study of the physical processes in the northern high-latitude (or simply Arctic) ionosphere. In addition to the main focus, two further studies are also presented regarding midlatitude ionosphere and neutral atmospheric simulations and observations. This section presents some basic background and the motivation behind these research topics. Durgonics, Tibor; H\oeg, P; Olsen, N; Coster, AJ; Wintoft, P; Komjathy, A; von Benzon, H; Published by: Published on: |
2016 |
Ionospheric data assimilation and forecasting during storms Chartier, Alex; Matsuo, Tomoko; Anderson, Jeffrey; Collins, Nancy; Hoar, Timothy; Lu, Gang; Mitchell, Cathryn; Coster, Anthea; Paxton, Larry; Bust, Gary; Published by: Journal of Geophysical Research: Space Physics Published on: |
Reply to comment by Kil et al. on “The night when the auroral and equatorial ionospheres converged” Martinis, Carlos; Baumgardner, Jeffrey; Mendillo, Michael; Wroten, Joei; Coster, Anthea; Paxton, Larry; Published by: Journal of Geophysical Research: Space Physics Published on: |
2015 |
This paper presents an epoch analysis of global ionosphere responses to recurrent geomagnetic activity during 79 corotating interaction region (CIR) events from 2004 to 2009. The data used were GPS total electron content (TEC) data from the Madrigal Database at the Massachusetts Institute of Technology Haystack Observatory and the electron density (Ne) data obtained from CHAllenging Minisatellite Payload (CHAMP) observations. The results show that global ionosphere responses to CIR events have some common features. In high and middle latitudes, the total electron content (TEC) showed a significant positive response (increased electron densities) in the first epoch day. A negative TEC response occurred at high latitudes of the American sector following the positive response. The CHAMP Ne showed a daytime positive response in all latitudes and a nighttime negative response in the subauroral region. These negative TEC and Ne responses were found to be related to thermospheric composition (O/N2) changes during the storms. At all latitudes, the maximum of the TEC positive effect always occurred at 2\textendash6 h after the CIR starting during local daytime and 10\textendash18 h later for the CIR onset during local nighttime. Case studies indicate that the TEC and Ne positive response had a strong dependence on the southward component (Bz) of the interplanetary magnetic field and solar wind speed. This suggests that penetration electric fields that were associated with changes in solar winds might play a significant role in the positive ionospheric response to storms. During the recovery time of the CIR-produced geomagnetic activity, the TEC positive disturbance at low latitudes sometimes could last for 2\textendash4 days, whereas at middle to high latitudes the disturbance lasted only for 1 day in most cases. A comparison of the ionospheric responses between the American, European and Asian sectors shows that the ionosphere response in the North American sector was stronger than that in the other two regions. The response of foF2 to the CIR events in middle to high latitudes showed a negative response for 2\textendash3 days after the first epoch day. This is different from the response of TEC, which was mostly positive during the same period of time. Chen, Yanhong; Wang, Wenbin; Burns, Alan; Liu, Siqing; Gong, Jiancun; Yue, Xinan; Jiang, Guoying; Coster, Anthea; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2015 YEAR: 2015   DOI: 10.1002/2014JA020657 CIR events; epoch study; Ionospheric response; recurrent geomagnetic activity |
Community-wide model validation study for systematic assessment of ionosphere models Shim, Ja; Kuznetsova, Maria; Rastaetter, Lutz; Bilitza, Dieter; Bingham, Suzy; Bust, Gary; Calfas, Roy; Codrescu, Mihail; Coster, Anthea; Crowley, Geoff; , others; Published by: Published on: |
The night when the auroral and equatorial ionospheres converged Martinis, C; Baumgardner, J; Mendillo, M; Wroten, J; Coster, A; Paxton, L; Published by: Journal of Geophysical Research: Space Physics Published on: |
2013 |
Ionospheric symmetry caused by geomagnetic declination over North America We describe variations in total electron content (TEC) in the North American sector exhibiting pronounced longitudinal progression and symmetry with respect to zero magnetic declination. Patterns were uncovered by applying an empirical orthogonal function (EOF) decomposition procedure to a 12 year ground-based American longitude sector GPS TEC data set. The first EOF mode describes overall average TEC, while the strong influence of geomagnetic declination on the midlatitude ionosphere is found in the second EOF mode (or the second most significant component). We find a high degree of correlation between spatial variations in the second EOF mode and vertical drifts driven by thermospheric zonal winds, along with well-organized temporal variation. Results strongly suggest a causative mechanism involving varying declination with longitude along with varying zonal wind climatology with local time, season, and solar cycle. This study highlights the efficiency and key role played by the geomagnetic field effect in influencing mesoscale ionospheric structures over a broad midlatitude range. Zhang, Shun-Rong; Chen, Ziwei; Coster, Anthea; Erickson, Philip; Foster, John; Published by: Geophysical Research Letters Published on: 10/2014 YEAR: 2013   DOI: 10.1002/grl.v40.2010.1002/2013GL057933 geomagnetic field; midlatitude ionosphere; thermospheric winds; total electron content |
2012 |
Ionospheric and thermospheric variations associated with prompt penetration electric fields Lu, G.; Goncharenko, L.; Nicolls, M.; Maute, A.; Coster, A.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2012 YEAR: 2012   DOI: 10.1029/2012JA017769 |
2011 |
Coupling Through Planetary Waves: from the Stratosphere to Ionospheric Irregularities Goncharenko, Larisa; Coster, Anthea; Chau, Jorge; Published by: To propose an observational strategy that would investigate potential effects of planetary waves on irregularities Published on: |
2010 |
Ionospheric response to the initial phase of geomagnetic storms: Common features Wang, Wenbin; Lei, Jiuhou; Burns, Alan; Solomon, Stanley; Wiltberger, Michael; Xu, JiYao; Zhang, Yongliang; Paxton, L.; Coster, Anthea; Published by: Journal of Geophysical Research Published on: Jan-01-2010 YEAR: 2010   DOI: 10.1029/2009JA014461 |
2008 |
A data-model comparative study of ionospheric positive storm phase in the midlatitude F region Lu, G; Goncharenko, LP; Coster, AJ; Richmond, AD; Roble, RG; Aponte, N; Paxton, LJ; Published by: Published on: |
2007 |
Tsugawa, T.; Zhang, S.-R.; Coster, A.; Otsuka, Y.; Sato, J.; Saito, A.; Zhang, Y.; Paxton, L.; Published by: Journal of Geophysical Research Published on: Jan-01-2007 YEAR: 2007   DOI: 10.1029/2007JA012415 |
Observations of a positive storm phase on September 10, 2005 In this study, we present multi-instrument observations of a strong positive phase of ionospheric storm, which occurred on September 10, 2005 during a moderate geomagnetic storm with minimum Dst=-60\ nT and maximum Kp=6\textendash. The daytime electron density measured by the Millstone Hill incoherent scatter radar (42.6\textdegreeN, 288.5\textdegreeE) increased after 13\ UT (\~8\ LT) compared with that before the storm. This increase is observed throughout the daytime, lasts for about 9\ h, and covers F-region altitudes above \~230\ km. At the altitude of 300\ km, the maximum increase in Ne reaches a factor of 3 by 19:30\textendash20:00\ UT and is accompanied by a \~1000\ K decrease in electron temperature, a \~100\textendash150\ K increase in ion temperature, and a strong upward drift. Observations by Arecibo ISR (18.3\textdegreeN, 293.3\textdegreeE) reveal similar features, with the maximum increase in electron density reaching a factor of 2.5 at 21:30\ UT, i.e. 1.5\textendash2\ h later than over Millstone Hill. The GPS TEC data show that the increase in electron density observed at Millstone Hill and Arecibo is only a part of a global picture reflected in TEC. The increase in TEC reaches a factor of 2 and covers middle and low latitudes at 19\ UT. At later times this increase moves to lower latitudes. A combination of mechanisms were involved in generation of positive phase. The penetration electric field resulted in Ne enhancements at subauroral and middle latitudes, the TAD/TID played an important role at middle and lower latitudes, and increase in O/N2 ratio could contribute to the observed positive phase at middle and lower latitudes. The results show the importance of an upward vertical drift at \~140\textendash250\ km altitude, which is observed for sustained period of time and assists in the convergence of ionization into the F-region. Goncharenko, L.P.; Foster, J.C.; Coster, A.J.; Huang, C.; Aponte, N.; Paxton, L.; Published by: Journal of Atmospheric and Solar-Terrestrial Physics Published on: 07/2007 YEAR: 2007   DOI: 10.1016/j.jastp.2006.09.011 |
Tsugawa, T; Zhang, S-R; Coster, AJ; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, LJ; Published by: Journal of Geophysical Research: Space Physics Published on: |
2006 |
We investigate the variations in the thermosphere and ionosphere using multi-instrument observations during the April 2002 period, with a particular focus on periods during small geomagnetic disturbances. Large and long-lasting reductions in the daytime electron density were observed at midlatitudes by incoherent scatter radars, ionosondes, and GPS receivers. These reductions reached 30\textendash50\% and were observed over an extended longitudinal area. They propagated to middle latitudes (35\textendash40\textdegreeN) in the case of a weak geomagnetic disturbance (Kp = 3-) and to low latitudes (0\textendash10\textdegreeN) in the case of a stronger disturbance (Kp = 5-). Data from the GUVI instrument aboard the TIMED satellite reveal a reduction in the daytime O/N2 ratio in the coincident area. Similar decreases are also predicted by the TIMEGCM/ASPEN model in both O/N2 ratio and electron density, though the magnitude of the decrease from the model is smaller than observed. We suggest that these ionospheric and thermospheric disturbances result from high-latitude energy input and efficient transport of regions with reduced O/N2 to lower latitudes. We discuss the possible role of a strong positive By component of the interplanetary magnetic field in the transport of regions with reduced O/N2. Goncharenko, L.; Salah, J.; Crowley, G.; Paxton, L.; Zhang, Y.; Coster, A.; Rideout, W.; Huang, C.; Zhang, S.; Reinisch, B.; Taran, V.; Published by: Journal of Geophysical Research Published on: 03/2006 YEAR: 2006   DOI: 10.1029/2004JA010683 Electron density; thermospheric composition; thermospheric wind |
Summer-Winter Hemispheric Asymmetry of Sudden Increase in Ionospheric Total Electron Content Tsugawa, T; Zhang, S; Coster, A; Otsuka, Y; Sato, J; Saito, A; Zhang, Y; Paxton, L; Published by: Published on: |
Goncharenko, L; Salah, J; Crowley, G; Paxton, LJ; Zhang, Y; Coster, A; Rideout, W; Huang, C; Zhang, S; Reinisch, B; , others; Published by: Journal of Geophysical Research: Space Physics Published on: |
Kozyra, JU; Shibata, K; Fox, NJ; Basu, S; Coster, AJ; Davila, JM; Gopalswamy, N; Liou, K; Lu, G; Mann, IR; , others; Published by: Published on: |
2003 |
Variability in the Mesosphere/Thermosphere/Ionosphere System During the Quiet Time of April 2002 Goncharenko, LP; Salah, J; Coster, A; Rideout, W; , Zhang; Paxton, L; Zhang, Y; Crowley, G; , Taran; Reinisch, B; , others; Published by: Published on: |
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