Astrid Maute, Art Richmond, Ben Foster The NCAR Themosphere-Ionosphere-Electrodynamics General Circulation Model: Problems in Developing a Realtistic Model Astrid Maute, Art Richmond, Ben Foster 22 May 2007

Description of the system Outline Description of the system Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) Our Experiment SAMSI meeting 22 May 2007

Electron and Neutral Density Day-night difference SAMSI meeting 22 May 2007

Spatial Variation: Equator CHAMP satellite at 12 LT Magnetic perturbation on the ground 2001-09-10,7:30-8:03, long=67., F10.7=245 b0  B [nT] 10 -10 -20 -30 -40 observations mag. latitude [deg] 20 40 H at 12 SLT [Luehr et al. 2003] upward ExB drift at magn. equator DH northward DD eastward SAMSI meeting 22 May 2007

Spatial Variation: High Latitude field-aligned current open field lines coupling to the magnetosphere night closed field lines +/- electric potential [Richmond et al. 2000] SAMSI meeting 22 May 2007

Geomagnetic grid geomagnetic equator SAMSI meeting 22 May 2007 [Richmond 1995] SAMSI meeting 22 May 2007

Geomagnetic / Geographic Grid equivalent current geomagnetic equator magnetic perturbation at 12 LT 17 UT 13 UT geog. longitude Variation with longitude DD eastward [Doumbia et al. 2007] SAMSI meeting 22 May 2007

Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM) Self-consistently calculates neutral and ion densities, composition, velocities, temperatures, along with electric fields and currents, between 97 and 500 km, assuming vertical hydrostatic equilibrium. Basic resolution is 5x5 degrees horizontally, ½ scale height (3-30 km) vertically, dimensioned 73(longitude) x 36 (latitude) x 29 (height) 1-day simulation uses ~ 3 minutes on bluevista, with 3-minute time step. SAMSI meeting 22 May 2007

TIE-GCM: Interacting Physics high latitude electric fields Global Electrodynamo neutral winds conductivities ion drag ion drag ion composition Thermosphere Ionosphere neutral composition tides at the lower boundary solar radiation, auroral precipitation, ion flux at upper boundary neutral temperature & wind input parameters internal parameters + many others SAMSI meeting 22 May 2007

TIE-GCM: How the models is used Studies of geomagnetic storms Yearlong runs for seasonal studies Model runs with daily varying input (e.g. using NCEP data) Generic input parameters to study certain effects Joule heating [mW/m2] for 18. Oct. 1995 storm Difference in temperature after doubling global CO2 concentration [Flyer of TIME-GCM] SAMSI meeting 22 May 2007

TIE-GCM: “tuning” the model Lots of parameters which would need tuning or could be improved Simplification of parameters, e.g. ignore latitudinal variation, seasonal dependence Model response is not necessarily linear, i.e. cannot “tune” for one parameter after another SAMSI meeting 22 May 2007

Observations Local with varying local time and location Dependence on season, solar cycle and activity Datatypes: neutral wind, electron density, magnetic field, drift velocity, neutral density Local time [Scherliess et al. 1999] Jicamarca 1968-92 Kp<3 Sa > 150 100 < Sa < 150 Sa < 100 SAMSI meeting 22 May 2007

Empirical models International Reference Ionosphere (IRI) model Mass-Spectrometer-Incoherent-Scatter (MSIS) model Global, can define specific conditions Log10 Ne [1/cm3] at 12 LT at equator IRI 2001 TIE-GCM Electron density (Ne) in TIE-GCM 40 to 60% too low depending on altitude Increase of DB in our experiment SAMSI meeting 22 May 2007

MSIS and IRI SAMSI meeting 22 May 2007

Our First Plan Initial plan was to vary 7 parameters: Tidal input (2,2) and (2,4) mode with amplitude and phase 4 parameters Eddy diffusion Burnside factor Nighttime electron density Use data from IRI (electron density height and magnitude of peak density), DB, drift velocities, MSIS (composition, temperature) SAMSI meeting 22 May 2007

Our Experiment Reduce to 3 parameters: Tidal input (2,2) migrating mode with amplitude and phase Range for amplitude [0,360] m and phase [0,12] hrs Nighttime electron density (internal parameter) Range for log10 Ne [3,4] 1/cm3 Use data from DB, drift velocities at different stations SAMSI meeting 22 May 2007

Why these parameters? prereversal enhancement in the early evening no influence on daytime nighttime changes LT tides influence the daytime drift, as well as time and magnitude of early evening peak [Fesen et al. 2000] LT SAMSI meeting 22 May 2007

Influence of tidal modes on DB Fuquene (geog. lat./long. = 5.3o/ -74.o) H D observation background determine tidal amplitude and phase least square fitting to magnetic perturbations around the world (2,6) tidal modes (2,5) (2,4) phase shift: 0 & 3 hrs (2,3) (2,2) SAMSI meeting 22 May 2007

Datatypes Conditions: solar minimum, quite time, equinox Use data from DB, drift velocities at different stations STS MH ARC MU JRO magnetic perturbation drift velocities SAMSI meeting 22 May 2007

Asian/Australian sector Example: B American sector Asian/Australian sector SJG FRD FUQ PIL HUA TRW AIA magn. latitude 60 40 20 -20 -40 -60 6 12 18 24 MLT H PET MGD KAK KOR GUA PMG BRS TOO H magn. latitude 60 40 20 -20 -40 -60 6 12 18 24 MLT 100 = 30 nT TIEGCM Observations HAO colloquium 8 September 2004

30 TIE-GCM runs Amplitude of (2,2) migrating tide: [0,360] m Phase of (2,2) migrating tide: [0,12] hrs Nighttime electron density: log10 Ne [3,4] 1/cm3 Error on our code: electrons and ions not in balance SAMSI meeting 22 May 2007

30 TIE-GCM runs SAMSI meeting 22 May 2007

SAMSI meeting 22 May 2007

SAMSI meeting 22 May 2007

SAMSI meeting 22 May 2007

SAMSI meeting 22 May 2007

SAMSI meeting 22 May 2007