Average behavior of the midlatitudeF-region parametersNT,Nmax, and τ during geomagnetic storms

Mendillo, M.; Papagiannis, Michael D.; Klobuchar, J. A.

doi:10.1029/ja077i025p04891

Cited by 60 publications

(32 citation statements)

References 12 publications

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“…While case studies of TEC storm effects are obviously prominent in the current literature (e.g., Foster and Rideout, 2005), they focus only on positive phase effects re-named "storm enhanced densities" (SEDs), morphology patterns that do not depend on precise knowledge of absolute values. This is not the case for negative storm TEC patterns when absolute calibration uncertainties have a profound effect upon percent changes, and particularly so at night when ionospheric trough values can be smaller than 4-6 TEC units in the sub-auroral domain; (4) finally, a significant number of past studies have been conducted at sub-auroral locations along the ∼70 W meridian (Matsushita, 1959;Mendillo et al, 1972;Mendillo and Klobuchar, 2006) and thus validation with previous work can be done. For all of these reasons, NmF2 values formed from observed foF2 data constitute the parameter of choice.…”

Section: Two Sub-auroral Equivalent Geophysical Ionospheric Locationsmentioning

confidence: 83%

Ionospheric storms at geophysically-equivalent sites – Part 1: Storm-time patterns for sub-auroral ionospheres

Mendillo

Narvaez

2009

Ann. Geophys.

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Abstract. The systematic study of ionospheric storms has been conducted primarily with groundbased data from the Northern Hemisphere. Significant progress has been made in defining typical morphology patterns at all latitudes; mechanisms have been identified and tested via modeling. At higher mid-latitudes (sites that are typically sub-auroral during non-storm conditions), the processes that change significantly during storms can be of comparable magnitudes, but with different time constants. These include ionospheric plasma dynamics from the penetration of magnetospheric electric fields, enhancements to thermospheric winds due to auroral and Joule heating inputs, disturbance dynamo electrodynamics driven by such winds, and thermospheric composition changes due to the changed circulation patterns. The ∼12 • tilt of the geomagnetic field axis causes significant longitude effects in all of these processes in the Northern Hemisphere. A complementary series of longitude effects would be expected to occur in the Southern Hemisphere. In this paper we begin a series of studies to investigate the longitudinal-hemispheric similarities and differences in the response of the ionosphere's peak electron density to geomagnetic storms.The ionosonde stations at Wallops Island (VA) and Hobart (Tasmania) have comparable geographic and geomagnetic latitudes for sub-auroral locations, are situated at longitudes close to that of the dipole tilt, and thus serve as our candidate station-pair choice for studies of ionospheric storms at geophysically-comparable locations. They have an excellent record of observations of the ionospheric penetration frequency (foF2) spanning several solar cycles, and thus are suitable for long-term studies. During solar cycle #20 (1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976), 206 geomagnetic storms occurred that had A p ≥30 or K p ≥5 for at least one day of the storm. Our analCorrespondence to: C. Narvaez (cnarvaez@bu.edu) ysis of average storm-time perturbations (percent deviations from the monthly means) showed a remarkable agreement at both sites under a variety of conditions. Yet, small differences do appear, and in systematic ways. We attempt to relate these to stresses imposed over a few days of a storm that mimic longer term morphology patterns occurring over seasonal and solar cycle time spans. Storm effects versus season point to possible mechanisms having hemispheric differences (as opposed to simply seasonal differences) in how solar wind energy is transmitted through the magnetosphere into the thermosphere-ionosphere system. Storm effects versus the strength of a geomagnetic storm may, similarly, be related to patterns seen during years of maximum versus minimum solar activity.

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Section: Two Sub-auroral Equivalent Geophysical Ionospheric Locationsmentioning

confidence: 83%

Ionospheric storms at geophysically-equivalent sites – Part 1: Storm-time patterns for sub-auroral ionospheres

Mendillo

Narvaez

2009

Ann. Geophys.

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“…These increase/decrease are known as positive/negative ionospheric storms, which are found to depend on time of the day, longitude and season (e.g., Mendillo et al, 1972;Balan and Rao, 1990). Excellent review articles on ionospheric storms are presented by Rishbeth (1991), Prolss (1995) and Abdu (1997).…”

Section: Introductionmentioning

confidence: 98%

Response of the ionosphere to super geomagnetic storms: Observations and modeling

Lekshmi

Balan

Vaidyan

et al. 2008

Advances in Space Research

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“…Mendillo et al, 1972;Mendillo and Klobuchar, 1974) have examined the TEC patterns of storm-time disturbances as measured by the departure from the average behavior. These studies laid the foundation for much of the work that has followed in the last 25 years.…”

Section: Introductionmentioning

confidence: 98%

“…The work of Mendillo et al (1972) used Faraday rotation measurements of TEC. Codrescu et al (2001) used TOPEX/POSEIDON measurements to derive the TEC climatology (up to 2000 km) as a function of geomagnetic activity.…”

Section: Introductionmentioning

confidence: 99%

Consistent features of TEC changes during ionospheric storms

Araujo-Pradere

Fuller‐Rowell

Spencer

2006

Journal of Atmospheric and Solar-Terrestrial Physics

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Average behavior of the midlatitudeF-region parametersN_T,N_max, and τ during geomagnetic storms

Cited by 60 publications

References 12 publications

Ionospheric storms at geophysically-equivalent sites – Part 1: Storm-time patterns for sub-auroral ionospheres

Ionospheric storms at geophysically-equivalent sites – Part 1: Storm-time patterns for sub-auroral ionospheres

Response of the ionosphere to super geomagnetic storms: Observations and modeling

Consistent features of TEC changes during ionospheric storms

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