Overview of Ionosphere-Thermosphere Modeling in CISMS.C. Solomon, A.G. Burns, G. Jee, T.L. Killeen, J. Lei, A. Maute, L. Qian, A.D. Richmond, R.G. Roble, W. Wang, M. Wiltberger, and Z. Zeng

High Altitude Observatory, National Center for Atmospheric Research

Abstract The Ionosphere-Thermosphere modeling component of the CISM project is responsible for development of general circulation models of the upper atmosphere system and their coupling to the magnetosphere. The Coupled Magnetosphere-Ionosphere-Thermosphere model (CMIT) consists of the Lyon-Fedder-Mobarry (LFM) Magnetosphere model coupled to the NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Studies using the coupled and stand-alone models show considerable improvement over empirical-model descriptions of the thermosphere and ionosphere. We are working on extending ionospheric models into the plasmasphere, collaborating with data assimilation activities, conducting an extensive validation effort, and including ion outflow in the feedback to the magnetosphere.

Center for Integrated Space Weather Modeling • Annual Site Visit • 5 June 2007

The Coupled Magnetosphere-Ionosphere-Thermosphere Model

(CMIT)

Plans and Goals

ITM Goals:Plasmasphere extension to TIE-GCMSolar Energetic Particle fluxes and ionizationHigh-resolution TIE-GCM in coupled modelsTransition to TIME-GCM in coupled modelsECMWF analysis fields at lower boundarySystematic ionospheric updates from GAIMNear-real-time solar irradiance inputsShort-term forecast of solar irradiance inputs

Cross-Thrust Goals:Inclusion of auroral acceleration moduleSpecification of ion outflow ratesPlasmaspheric coupling from the Rice Convection Model (RCM):

Electric FieldsPrecipitation

TIE-GCM

E

LFM

Magnetosphere -Ionosphere Coupler

Jll, np,Tp

Conductivities:p

h,

Winds: Jw

PJll

-JwParticle precipitation:

Fe, E0

Electric Potential:tot

GSWM

Ver

tical

Drif

t (m

/s)

Ver

tical

Drif

t (m

/s)

The December 2006 “AGU Storm”

CMIT simulations of Total Electron Content (TEC). GPS measurements of Total Electron Content.

Vertical ion drift at the magnetic equator during the April 2004 “CAWSES” event — simulations by the stand-alone TIE-GCM and CMIT compared to radar measurements at Jicamarca.

The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model

(TIE-GCM)

Neutral density simulations over the declining phase of solar cycle 23 made by the NCAR TIE-GCM using observed solar spectral irradiance inputs from measurements by the TIMED Solar EUV Experiment. Comparison to satellite drag density measurements shows improved agreement over empirical models.

Comparison of TIE-GCM ionospheric climatology at low solar activity during summer 2006 to initial measurements by the COSMIC satellites using GPS occulations.