Near Real Time CTIPe

Project Team

Mihail Codrescu

Tim Fuller-Rowell

Mariangel Fedrizzi

Catalin Neagrea

Tomoko Matsuo

Naomi Maruyama

George Millward


The reliance of our society on technologies that are sensitive to space weather disturbances has increased in the last few decades. New systems being designed today require more and more accurate knowledge of the space environment in order to fulfill their missions.

The size and the complexity of the thermosphere-ionosphere system make it impossible to measure all relevant parameters continuously. However, the available measurements can be successfully used to constrain the results of physically-based numerical models which in turn can supply the missing information.

In this project we use the model in an effort to provide specification of the thermosphere and ionosphere in real time. We use F10.7 and ACE measured IMF, solar wind (SW) velocity and density to force the global circulation model. Due to the 30 minute propagation time of SW to the nose of the magnetosphere we are able to provide a 10-20 minute forecast for the model results. We show neutral temperature, electron density, mean molecular mass, nmF2, hmF2, TEC, and model inputs in a quick look format. We compare our model results with measurements and other model results, build statistics and display them on this page under Validation.


The coupled thermosphere ionosphere plasmasphere electrodynamics (CTIPe) model is a non-linear, coupled thermosphere-ionosphere-plasmasphere physically based numerical code that includes a self-consistent electrodynamics scheme for the computation of dynamo electric fields. The model consists of four distinct components which run concurrently and are fully coupled. Included are a global thermosphere, a high-latitude ionosphere, a mid and low-latitude ionosphere/plasmasphere and an electrodynamical calculation of the global dynamo electric field. model has evolved from an integration of a neutral thermospheric code and a high- and mid-latitude ionospheric model.

Thermosphere Model

The thermospheric model was originally developed by Fuller-Rowell (Fuller-Rowell and Rees , [1980], Rees et al. , [1980]) and is fully described in the PhD thesis of Fuller-Rowell [1981]. The high-latitude ionospheric model was developed by S. Quegan (Quegan , [1982]; Quegan et al. , [1982]). The model of the Earth's mid- and low-latitude plasmasphere is based on the model of Bailey [1983]. These first three components are described in more detail under the name of coupled thermosphere ionosphere plasmasphere (CTIP) by Millward et al. , [1996]. The electrodynamic calculation was developed by Richmond and Roble , [1987] and was included in the CTIP model by Millward , [2001] resulting in the creation of CTIPe.

The thermospheric code simulates the time-dependent structure of the wind vector, temperature, and density of the neutral thermosphere by numerically solving the non-linear primitive equations of momentum, energy, and continuity. The global atmosphere is divided into a series of elements in geographic latitude, longitude, and pressure. Each grid point rotates with Earth to define a non-inertial frame of reference in a spherical polar coordinate system. Latitude resolution is 2 deg., and longitude resolution is 18 deg.. Each longitude slice sweeps through local time with a one-minute time step. In the vertical direction the atmosphere is divided into 15 levels, in logarithm of pressure, from a lower boundary of 1 Pa at 80 km altitude, to an altitude above 500 km.

The momentum equation is non-linear, and the solution describes the horizontal and vertical advection, curvature and Coriolis effects, pressure gradients, horizontal and vertical viscosity, and ion drag. The non-linear energy equation is solved self-consistently with the momentum equation; it describes three-dimensional advection, and the exchange between internal, kinetic, and potential energy. The solutions also describe horizontal and vertical heat conduction by both molecular and turbulent diffusion, heating by solar UV and EUV radiation, Joule heating, and cooling by infrared radiation.

Time-dependent major species composition equations are solved including the evolution of O, O2, and N2, under chemistry, transport and mutual diffusion Fuller-Rowell et al., (1994). The time-dependent variables of southward and eastward wind, total energy density, and concentrations of O, O2, and N2 are evaluated at each grid point by an explicit, time-stepping numerical technique. After each iteration the vertical wind, the temperature, the density, and the heights of pressure surfaces are derived. The parameters can be interpolated to fixed heights for comparison with experimental data.

The model includes a chemical heat source due to the recombination of O+. This is important for the low latitude temperature structure as the large amount of ionization in the equatorial-anomaly crests after sunset turns out to be a significant heat source Fuller-Rowell et al., (1997). The ionization, heating, and dissociation rates due to solar EUV radiation are calculated following Solomon and Qian (2005). The NO cooling is calculated using the NO model of D. Marsh (2004).

Ionosphere Model

The equations for the neutral thermosphere are solved self-consistently with a high- and mid-latitude ionospheric convection model Quegan et al. (1982). The ionosphere is computed self-consistently with the thermosphere poleward of 23 deg. latitude in both hemispheres. In this coupled model the ionospheric Lagrangian frame has been modified to be more compatible with the Eulerian frame by the use of a semi-Lagrangian technique Fuller-Rowell et al. (1987, 1988).

Transport under the influence of the magnetospheric electric field is explicitly treated, assuming ExB drifts and collisions with the neutral particles. The densities of atomic ions H+ and O+ and the ion temperature are evaluated over the height range from 100 to 10,000 km, including horizontal transport, vertical diffusion and the ion-ion and ion-neutral chemical processes. Below 400 km the additional contribution from the molecular ion species N2+, O2+, and NO+ and the atomic ion N+ are included. The ion temperature is calculated under the assumption of thermal balance between heat gained from the electron gas and from ion-neutral frictional heating, and heat lost to the neutral gas.

Plasmasphere Model

In addition to the thermosphere and high-latitude ionosphere components detailed above, a separate and more complete version of CTIM also includes a fully dynamic and coupled description of the mid- and low-latitude ionosphere and plasmasphere (CTIP). The enhancement works by solving the relevant equations of continuity, momentum and energy for the ions O+ and H+ and for the electrons, in much the same way as is done for the high-latitude ionosphere. The equations are solved along a large number of independent, closed, magnetic flux-tubes, orientated along an assumed eccentric dipole magnetic field. The effects of ExB drift due to the dynamo action of neutral winds, critical for accurate modelling of the equatorial ionosphere, are at present included as an empirical description. Complex three dimensional interpolation routines are used to provide a full coupling between the ionosphere/plasmasphere and thermsophere components.

Electrodynamic Calculation

The electrodynamic calculation was developed by Richmond and Roble, (1987) and was included in the CTIP model by Millward, (2001) resulting in the creation of CTIPe. The calculation includes prompt penetration electric fields following Manoj et al. (2008).

Common Inputs

The magnetospheric input to the model is based on the statistical models of auroral precipitation and electric fields described by Fuller-Rowell and Evans (1987) and Weimer (2005), respectively. Both inputs are keyed to solar wind measurements from ACE and/or DICOVR.

The lower boundary condition in CTIPe is based on a free run of the Whole Atmosphere Model (WAM). Ionization rates from the EUV flux are evaluated from reference spectra for high and low solar activity on the basis of the Atmospheric Explorer (AE) measurements. The tidal inputs at the lower boundary are based on results from the global-scale wave model (GSWM) Hagan et al., (1995; 1999). The inclusion of the tidal forcing at the lower boundary as opposed to a higher pressure level as was done in previous versions of the model is described by Mueller-Wodrag et al., (2001).

The joule heating calculation at high latitudes includes the effects of small-scale fluctuations in the E-field. The amplitude and spatial distribution of applied fluctuations is based on Millstone Hill Incoherent Scatter Radar data Codrescu et al., (2000). The average field at each grid point follows the diurnal variation prescribed by the Weimer model, while the small scale fluctuations are updated every minute. This procedure improves the neutral temperature structure as compared with MSIS.


The scripts to run the model and produce plots in real-time, based on inputs from the SWPC data base, were developed by Hargobind Khalsa. The webpage was designed and implemented by Stefan Codrescu.


Fedrizzi, Mariangel, Tim J. Fuller-Rowell, and Mihail V. Codrescu, Global Joule heating index derived from thermospheric density physics-based modeling and observations, SPACE WEATHER, VOL. 10, S03001, doi:10.1029/2011SW000724, 2012

Codrescu, Mihail V. Catalin Negrea, Mariangel Fedrizzi,T. J. Fuller-Rowell, Alison Dobin, Norbert Jakowsky, Hargobind Khalsa, Tomoko Matsuo, and Naomi Maruyama, A real-time run of the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model, SPACE WEATHER, VOL. 10, S02001, doi:10.1029/2011SW000736, 2012.

Codrescu, M. V., T. J. Fuller-Rowell, J. C. Foster, J. M. Holt, and S. J. Cariglia, Electric field variability associated with the Millstone Hill electric field model, J. Geophys. Res., 105, 5265,5273, 2000.

Foster, J.C., J.M. Holt, R.G. Musgrove and D.S. Evans, Geophys. Res. Lett., 13, 656-659, 1986.

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Fuller-Rowell, T.J., D. Rees, S. Quegan, R.J. Moffett, M.V. Codrescu, and G.H. Millward, STEP Handbook on Ionospheric Models (ed. R.W. Schunk), Utah State University, 1996.

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Manoj, C., S. Maus, H. Luehr, and P. Alken (2008), Penetration characteristics of the interplanetary electric field to the daytime equatorial ionosphere, J. Geophys. Res., 113, A12310, doi:10.1029/2008JA013381.

Millward, G.H., H. Rishbeth, T.J. Fuller-Rowell,A. Aylward, S. Quegan, and R.J. Moffett, J. Geophys. Res., 101, In press, March, 1996a.

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Stanley C. Solomon and Liying Qian, Solar extreme-ultraviolet irradiance for general circulation models, Journal of Geophysical Research, 110, A10306, doi:10.1029/2005JA011160, 2005.

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Last updated June 2018.

Thermosphere Ionosphere Modelling /