Overview of midlatitude ionospheric storms

Kintner, P. M.; Coster, A. J.; Fuller‐Rowell, T. J.; Mannucci, A. J.

doi:10.1029/2007eo370002

Cited by 6 publications

(3 citation statements)

References 11 publications

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“…Geomagnetic storms can impact the ionosphere over large geographical areas on time scales of days [ Fuller‐Rowell et al , 1994, 1996; Mendillo , 2006; Kintner et al , 2007]. Statistical analyses of NmF 2 from multiple ground‐based ionosondes suggest that “a large part of F2‐layer variability is linked to that of geomagnetic activity” [ Rishbeth and Mendillo , 2001, p. 1661] and that the solar irradiance component is minimal by comparison, even on time scales from 2 to 30 days [ Forbes et al , 2000; Rishbeth and Mendillo , 2001].…”

Section: Introductionmentioning

confidence: 99%

Ionospheric total electron content: Global and hemispheric climatology

et al. 2011

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[1] A new general linear model of the climatology of the ionosphere's total electron content (TEC) is described, accounting simultaneously for the influences of solar and geomagnetic activity, oscillations at four frequencies and a secular trend. The model captures more than 98% of the variance in the daily averaged, global TEC derived from GPS observations during the 16 years from 1995 to 2010, and enables the reconstruction of TEC variations since 1950. Solar EUV irradiance variations, the dominant ionospheric influence, directly increase TEC by as much as 40 TECU from solar activity minimum to maximum and produce additional 27-day fluctuations of as much as 15 TECU (in October 2003). Semiannual and annual oscillations in TEC are comparable in magnitude to the 27-day fluctuations, with (peak to valley) amplitudes that increase from a few TECU at low solar activity to ∼17 TECU during solar activity maximum. The phase and amplitude of the semiannual oscillation are identical in the northern and southern geographic hemispheres (and hence globally). In contrast, the annual oscillation is twice as large in the southern hemisphere (where it peaks in December-January) than in the northern hemisphere (where it peaks in April-May). Seasonal, semiannual and annual anomalies in TEC are direct effects of semiannual and annual oscillations produced by orbitally driven photoionization and thermospheric composition changes, not of corresponding oscillations in solar or geomagnetic activity. Geomagnetic influences on daily averaged global TEC are relatively modest, with the maximum effect a reduction of 11 TECU (in October 2003) and only 11 episodes in excess of 5 TECU depletions during the past 16 years.

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Section: Introductionmentioning

confidence: 99%

Ionospheric total electron content: Global and hemispheric climatology

et al. 2011

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“…The mechanisms driving these ionospheric changes are still a very active topic of research. The F‐region ionosphere is closely coupled to the thermosphere via composition, winds, and electrodynamics, which can all play a major role in producing ionospheric variability [e.g., Buonsanto , 1999; Kintner et al , 2007; Crowley et al , 2006; Crowley and Meier , 2008]. Because of this complexity through the various coupling mechanisms, it is still difficult to specify in real‐time, or to predict the ionospheric changes, yet there is a real operational need for such predictions to aid communication, navigation and surveillance systems.…”

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confidence: 99%

Periodic modulations in thermospheric composition by solar wind high speed streams

Crowley

Reynolds

Thayer

et al. 2008

Geophysical Research Letters

108

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ΣO/N2 ratios in the Earth's thermosphere are measured by the Global Ultraviolet Imager (GUVI) on the TIMED satellite, and demonstrate strong 9 and 7 day oscillations in 2005 and 2006, respectively, that are well correlated with the solar wind speed and Kp index. This work builds on the recently discovered connection between rotating solar coronal holes and thermospheric mass density variations. The work described here is the first description of geomagnetically forced periodicities in neutral composition. Furthermore, these observations provide the first definitive proof that the processes creating neutral composition changes during geomagnetic storms occur continuously at all activity levels and all over the world. The ΣO/N2 response versus the mass density response indicates the important role of vertical winds at high latitudes while thermal expansion dominates at lower latitudes.

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“…As Kintner et al . [] describe, the causes of mid‐latitude ionospheric storms have been reported to be external electric fields (from the inner magnetosphere, using an ionospheric model), internal neutral winds (using a thermosphere model), or some combination of both. Furthermore, the choice of how to specify pertinent parameters such as zonal neutral winds can dramatically affect the simulations [ Huba et al ., ], as do choices of other inputs, for example, the solar EUV spectral irradiance.…”

Section: Introductionmentioning

confidence: 99%

Geospace variability during the 2008–2009 Whole Heliosphere Intervals

et al. 2014

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We simulate the ionosphere and thermosphere throughout the extended solar minimum epoch from 2008 to 2009 using geospace models, systematically validating the models with databases of observed geospace composition. We isolate and quantify observed changes of as much as 4 total electron content unit (TECU) (1 TECU = 10 16 elections m À2 ) (~36%) in global (60°SÀ60°N) ionospheric total electron density and as much as 19 × 10 À12 kg m À3 (~75%) in global thermospheric mass density at 250 km associated with fluctuating solar EUV radiation and geomagnetic activity during this nominally "quiet" period. Corresponding modeled responses to both solar EUV radiation and geomagnetic activity are about a factor of 2 smaller than is observed. We identify, as well, semiannual and annual oscillations that produce geospace variability comparable to that produced by external solar and geomagnetic influences, and which cause distinct differences among the three individual Whole Heliosphere Intervals.

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Overview of midlatitude ionospheric storms

Cited by 6 publications

References 11 publications

Ionospheric total electron content: Global and hemispheric climatology

Ionospheric total electron content: Global and hemispheric climatology

Periodic modulations in thermospheric composition by solar wind high speed streams

Geospace variability during the 2008–2009 Whole Heliosphere Intervals

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