An improved phenomenological model of ionospheric density

Chiu, Y. T.

doi:10.1016/0021-9169(75)90035-5

Cited by 266 publications

(136 citation statements)

References 15 publications

Supporting

Mentioning

135

Contrasting

Unclassified

Order By: Relevance

“…CTIM simulates the three-dimensional global thermosphere and the three-dimensional high-latitude ionosphere by solving neutral and ion fluid equations with solar radiation, tidal modes, and magnetospheric energy input. For a low-latitude ionosphere below 23°geographic latitude, CTIM uses a empirical model of Chiu (1975).…”

Section: Openggcm-ctimmentioning

confidence: 99%

Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

Connor

Zesta

Fedrizzi

et al. 2016

J. Space Weather Space Clim.

View full text Add to dashboard Cite

The magnetosphere is a major source of energy for the Earth's ionosphere and thermosphere (IT) system. Current IT models drive the upper atmosphere using empirically calculated magnetospheric energy input. Thus, they do not sufficiently capture the stormtime dynamics, particularly at high latitudes. To improve the prediction capability of IT models, a physics-based magnetospheric input is necessary. Here, we use the Open Global General Circulation Model (OpenGGCM) coupled with the Coupled Thermosphere Ionosphere Model (CTIM). OpenGGCM calculates a three-dimensional global magnetosphere and a two-dimensional high-latitude ionosphere by solving resistive magnetohydrodynamic (MHD) equations with solar wind input. CTIM calculates a global thermosphere and a high-latitude ionosphere in three dimensions using realistic magnetospheric inputs from the OpenGGCM. We investigate whether the coupled model improves the storm-time IT responses by simulating a geomagnetic storm that is preceded by a strong solar wind pressure front on August 24, 2005. We compare the OpenGGCM-CTIM results with low-earth-orbit satellite observations and with the model results of Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe). CTIPe is an up-to-date version of CTIM that incorporates more IT dynamics such as a low-latitude ionosphere and a plasmasphere, but uses empirical magnetospheric input. OpenGGCM-CTIM reproduces localized neutral density peaks at~400 km altitude in the high-latitude dayside regions in agreement with in situ observations during the pressure shock and the early phase of the storm. Although CTIPe is in some sense a much superior model than CTIM, it misses these localized enhancements. Unlike the CTIPe empirical input models, OpenGGCM-CTIM more faithfully produces localized increases of both auroral precipitation and ionospheric electric fields near the high-latitude dayside region after the pressure shock and after the storm onset, which in turn effectively heats the thermosphere and causes the neutral density increase at 400 km altitude.

show abstract

Section: Openggcm-ctimmentioning

confidence: 99%

Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

Connor

Zesta

Fedrizzi

et al. 2016

J. Space Weather Space Clim.

View full text Add to dashboard Cite

show abstract

“…The ®rst coupled thermosphere-ionosphere interactive models avoided the dicult problem presented by the equatorial F2-layer, by resorting at low latitudes to a prescribed model of the electron density distribution, such as that of Chiu (1975), and of the electric ®eld (Richmond et al, 1980). Later it became possible to include the equatorial zone in the computations, with fully self-consistent dynamo calculations in which the E-region winds interact with the magnetic ®eld and currents (Richmond et al, 1992;Richmond, 1995).…”

Section: Modelling the Equatorial F-layermentioning

confidence: 99%

The equatorial F-layer: progress and puzzles

Rishbeth

2000

Ann. Geophys.

186

View full text Add to dashboard Cite

Abstract. This work reviews some aspects of the ionospheric F-layer in the vicinity of the geomagnetic equator. Starting with a historical introduction, brief summaries are given of the physics that makes the equatorial ionosphere so interesting, concentrating on the large-scale structure rather than the smaller-scale instability phenomena. Several individual topics are then discussed, including eclipse eects, the asymmetries of the`equatorial trough', variations with longitude, the semiannual variation, the eects of the global thermospheric circulation, and ®nally the equatorial neutral thermosphere, including`superrotation' and possible topographic in¯uences.

show abstract

“…The ion drag forcing and Joule heating within the diffuse aurora drive the neutral winds, and these terms depend on the structures and magnitudes of the ion densities and electric fields, which are derived from the ARIA I measurements. The background ion density is based on the Chiu (1975) empirical model, which has been used for simplicity to specify the background ionosphere, rather than newer models, since the background ion density is small relative to the ion density enhancements which are being used in this investigation. The magnitude and structure of the ion density enhancement and electric field can be modified in the model.…”

Section: Modelmentioning

confidence: 99%

“…Figures 5c and d show examples of the effects of changing the magnitude of the original ARIA I ion density enhancement, whilst the electric field from the same campaign and the background ion density estimated from the Chiu (1975) model are kept the same. Background winds include the (2,5) tidal mode, with constant amplitude 300 m and phase 3.0 h, introduced at the start of interval four.…”

Section: Ion Density Variationsmentioning

confidence: 99%

Sensitivity studies of the E region neutral response to the postmidnight diffuse aurora

Parish

Lyons

2006

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Measurements of the neutral thermosphere within the postmidnight substorm recovery phase diffuse aurora show very large horizontal winds, and strong vertical structure. Rocket, satellite, and ground based observations during the ARIA (Atmospheric Response in Aurora) campaigns, and earlier dawn side rocket observations, indicate neutral winds of up to 200 m/s, and a characteristic jet-like wind maximum around 110 to 120-km altitude, with strong shears above and below. The observed wind magnitudes are found to have a dependence on geomagnetic activity level, but recent modeling studies suggest that tides which propagate up from the troposphere and stratosphere may play an important role in generating the strong vertical variations in the neutral winds. The relative importance of auroral and tidal forcing in producing the measured wind structure is not known, however. Simulations have been performed using a three dimensional (3-D) high resolution limited area thermosphere model to understand the processes which generate the observed neutral structure within the postmidnight diffuse aurora. Parameters measured during the ARIA I observational campaign have been used to provide auroral forcing inputs for the model. Global background winds and tides have been provided by the CTIP (Coupled Thermosphere Ionosphere Plasmasphere) model. The sensitivity of the response of the neutral atmosphere to changes in different parameters has been examined. Variations in the amplitudes and phases of the propagating tides in the background winds are found to have significant effects on the neutral structure in the E region, and the wind structure below around 110 km is found to be mainly produced by tidal forcing. Changes in the electric field and ion density affect the winds above around 120 km, and the importance of auroral forcing is found to depend on background winds. Variations in the orientation of the aurora relative to the background field, which may be Correspondence to: H. F. Parish (helen@atmos.ucla.edu) caused by changes in the interplanetary magnetic field, are also found to modify the wind structure. When both auroral forcing and propagating tides are included, many of the basic characteristics of the wind structure are displayed, although the great strength of the wind shears is not well reproduced. The strength of the shears may be related to a currently unmodeled process, or to different types of waves.

show abstract

An improved phenomenological model of ionospheric density

Cited by 266 publications

References 15 publications

Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

Modeling the ionosphere-thermosphere response to a geomagnetic storm using physics-based magnetospheric energy input: OpenGGCM-CTIM results

The equatorial F-layer: progress and puzzles

Sensitivity studies of the E region neutral response to the postmidnight diffuse aurora

Contact Info

Product

Resources

About