The following summarizes changes to the TIEGCM model from v1.92 (released 2/23/2009) to v1.93 (released 6/3/2010):

Bug fixes

• qinite.F : increase night-time ionization rates which is necessary because the minimum electron density was removed in previous versions (elden.F)
• dynamo.F subroutine threed: the E_lam wasn't mapped in the horizontal plane which gave wrong results close to the geomagnetic equator at higher pressure levels (as a consequence EXB drift was wrong)
• efield.F in the mapping from magnetic to geographic grid real values are put into integer w/o explicit conversion from real to integer. This led to wrong mapping on 64-bit Linux systems.
• addiag.F: Use glat(j) instead of float(j) in calculation of c2, sub calczg. Sub calczg calculates gravity-varying geopotential (geometric height) field ZG.
• fft9.F: Add ntrigs argument to FFT99B call from sub FFT99
• Weimer05 model:wei05sc.F: Fix error in f90 translation in sub interpol_quad (see comments in wei05sc.F). Also add routines to work around non-ANSI trig functions.

New namelist read parameter KP

• KP can be specified either as a constant or multiple time-dependent values.
• If provided, empirical formulas will use the given KP to calculate CTPOTEN and/or POWER.

Change calculation of the sun's location from dipole coordinates to apex

• Update IGRF coefficients with IGRF11 in apex_subs.F

Option to write 4-byte floats or 8-byte doubles to secondary histories

• New namelist input parameter SECH_NBYTE can be either 4 (to write 4-byte floats), or 8 (to write 8-byte doubles). Default is SECH_NBYTE = 4

Script changes to enable parallel runs on hao 64-bit Linux systems

• Changes to tiegcm-linux.job and tgcm_config in the scripts directory.
• Add PGI/pgf90 MPI env vars to tiegcm-linux.job
• To build and execute an MPI run on a 64-bit Linux machine, set the following in tiegcm-linux.job:
• set mpi = TRUE
• set nproc = 4 or 8
• Then execute "tiegcm-linux.job >! tiegcm-linux.out" as usual.

Minor changes to scripts/tiegcm-ibm.job to accomodate mpi=FALSE under AIX

• Also minor change to imf.F for the same reason (4-byte vs 8-byte integers).

Year-end runs

• Run to model time 366,0,0 (for non-leap years), or to 367,0,0 (for leap years) This will be written to the history files as mtime 1,0,0 of the next year. The 1,0,0 history can be used as the Source to start the following year.

Release notes for TIEGCM version 1.92 (cvs tag tiegcm1-92) The following summarizes changes to the TIEGCM model from v1.91 (released 12/10/2008) to v1.92 (released 2/23/2009):

Science:

• Coupling macros and InterComm calls for coupling to the Lyon-Fedder-Mobarry (LFM) magnetospheric model are now included as build options. This forms the Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model. Specific changes are described below.

Software:

• Addition of CMIT pre-processor macros (#ifdef) in source for coupling to LFM. Changes to advance.F, aurora.F, dynamo.F, tgcm.F
• Three new source files: cism_adhoc.F, cism_coupling.F, cism_intercomm.F
• Added COUPLING=NO and COUPLING conditionals in scripts/Makefile, for standalone TIEGCM (i.e., CMIT coupling macros are not defined during build). CMIT mods were taken from revision 786 of the LTR-para repository.
• Restore correct version of qrj.F (an old version was inadvertantly included in tiegcm1.91).

The following summarizes changes to the TIEGCM model from v1.9 (released 6/20/2008) to v1.91 (released 12/10/2008):

Science:

• Subroutine wei05loc was added to wei05sc to properly position the auroral precipitation oval for use with the Weimer convection model. This improves correspondence between the convection and precipitation patterns, so the Weimer model, driven by IMF and solar wind data, is now ready for "friendly users." Heelis convection remains the default.
• The variables rote and roth that control the rotation of the precipitation oval, and associated comments, were re-written to clarify the units. No change was made to the existing (very small) amount of precipitation oval rotation as a function of hemispheric power.
• Modifications to the Heelis convection specification were made to restore full functionality. Asymmetry in the dawn/dusk convection cells was turned back on, and the IMF By effect can be included via namelist reads. A limit between -11 and +7 was placed on the range of By in the parameterization.

Software:

• Variable eflux2d was included in aurora.F to output auroral energy flux in secondary histories.
• J_pg added to J_e2 as well as J_e1 in dynamo.F and current.F
• Added initial_day attribute to the time variable
• Revised gswm.F for intel compiler
• Fixed addfld calls for 2d fields in advance.F
• Added logical function ismissing for reading IMF data in imf.F
• Removed unused subroutine defvar_f3d from nchist.F
• Added subroutine copyhist to hist.F so that structure sh is written to first history
• Fixed error print statement re rdays in nchist.F
• Fixed defs.h in commented-out section for vres=0.25 in tgcm_config
• Added model day time mtime(1)-365 to the output history for cases where mtime(1)>365 to support setup for next run across year boundaries
• Added check to insure non-negative N2 at interfaces in qrj.F and qinite.F
• Set sh%nflds and sh%fnames when reading source history in nchist.F to prevent crashes under linux

Known issues:

• Implementation of the Weimer high-latitude potential/convection model is not yet fully tested. Gaps in the solar wind / IMF input data will cause the model to stop.

The following summarizes changes to the TIEGCM model from v1.8 (released 1/10/2006) to v1.9 (released 6/20/2008):

Science:

• Removed minimum electron density restriction in elden.F and increased nighttime flux in qinite.F
• Effective electron-neutral collision frequency rnu_ne was increased by a factor of 4 in lamdas.F
• Updated apex_subs.F to include apex coefficients for 1995, 2000, 2005.
• Corrected Joule heating for ions, includng vertical velocity difference (qjoule.F).
• Significant changes to the auroral parameterization, including empirical relationships between Kp data (GPI run) and hpower and ctpoten. Also positioning of the oval wrt Weimer high latitude convection. Several parameters re the precipitation oval in aurora.F were also changed.
• By default, GSWM migrating diurnal and semi-diurnal tidal perturbations are used. GSWM non-migrating tides are available via namelist read, but are turned off by default.

Software:

• New CF-compliant netcdf history files have separate vertical coordinate arrays for midpoints (lev), and interfaces (ilev).
• Module addfld replaces addfsech and related routines as a single-interface for saving fields on secondary histories.
• Add gravity-varying geopotential height field (with latitude gradient) to secondary histories (ZG). Also add geopotential on the magnetic grid (ZMAG).
• Default resolution is 5 deg lat x lon, dlev=0.5. The code builds and executes at 2.5 deg and dlev=0.25, but has not been extensively tuned or tested at the double resolution (may require step < 120)
• Add section in Makefile for use of ifort compiler by DASG machines and other intel systems. Also some simplification of scripts/Makefile template.
• Simplification of the electric field calculation (remove redundancy)
• Remove annual tide option (was bndry_annual in bndry.F)
• Remove dynamo=0 option (remove source nodynamo.F)
• Removed read of external file magvol (magfield.F). Now calling apex code unconditionally.
• Bug fix in sub mp_gather2root_sechist (mpi.F)
• Replace hardwired joule heating multiplication factor of 1.5 with named parameter joulefac in duv.F
  (Value of 1.5 was *not* changed)
• Improved filtering mechanism, similiar to timegcm, also some changes to allow proper filtering for the 2.5 deg model.
• Add $lib_netcdf and $inc_netcdf shell vars in job scripts (they are passed to tgcm_config), to facilitate installation and compilation at external non-NCAR sites.
• Flexibility for the user in either providing constants or time dependent values for certain solar-related input parameters via namelist read, OR reading data from external data files (NGDC GPI or NASA/OMNI IMF). These input parameters include ctpoten,hpower,bximf, byimf,bzimf,swden,swvel,f107d, and f107a.
• Add license agreement file tiegcmlicense.txt to the source code directory, and add reference to this file at the top of all source files.

Known issues:

• Implementation of the Weimer high-latitude potential/convection model is not functioning properly because the precipitation oval does not always correspond to the Weimer pattern. Use of the Wiemer model is not recommended until this major code issue is resolved. Heelis convection remains the default.
• Daytime E-region electron densities are still about 30% too low when the model is run using EUVAC or SEE data solar inputs.
• Auroral generation of nitric oxide during higher levels of activity are probably on the low side.
• The O-O+ collision frequency is a matter of continuing debate. The model default Burnside Factor (COLFAC) remains 1.5. There is some laboratory and empirical evidence that 1.3 may be a better value. This can be set via the namelist input parameter COLFAC.
• Joule heating is increased by a factor of 1.5 by default, to account for sub-grid-scale and related effects. This factor (JOULEFAC, in dt.F) is also a matter of debate.
• Seasonal effects on density and composition (annual and semi-annual variation) are only partially accounted for in the current model configuration, since the lower boundary eddy diffusivity coefficient is constant.
• GSWM non-migrating tides are not yet validated and are off by default. They may be turned on via namelist input, but this is not recommended.
• There are some questions about the neutral dynamics near the lower boundary, so winds at the lowest few levels should be treated with skepticism.
• During significant storms, plasma may be driven to altitudes above the model upper boundary and lost, leading to unrealistic high-altitude ionospheric densities.
• O(1D) excitation by thermal electrons is turned off. Improved photoelectron heating and new cooling rates will be addressed in future versions.
• High-resolution grid (2.5 x 2.5 x H/4) is not verified and should not be used.

New features and options:

• Introduction of the 2005 Dan Weimer high-latitude electric potential model option (see module wei05sc.F)
  

  Please note:

    The Weimer model of high-latitude potential is the intellectual property of 
    Daniel Weimer and may not be extracted, distributed, or used for any purpose 
    other than as implemented in the TIE-GCM.  For further information concerning 
    this model, please contact Dan Weimer (dweimer@vt.edu).
    

• Namelist read parameter POTENTIAL_MODEL can now be one of the following:

      POTENTIAL_MODEL = 'HEELIS'   ; default potential model
      POTENTIAL_MODEL = 'WEIMER01' ; 2001 Weimer model
      POTENTIAL_MODEL = 'WEIMER05' ; 2005 Weimer model (new in tiegcm1.9)
      POTENTIAL_MODEL = 'NONE'     ; no potential model
    

• Import of NASA/OMNI IMF data to optionally drive the Weimer potential model (namelist read parameter IMF_NCFILE). See tiegcm IMF data import
  

  Please note:

  The option of using the Weimer 2005 potential model driven with IMF data is provisionally released in TIEGCM 1.9. We have made no effort to fill data gaps, and additional work is needed to insure proper positioning of the auroral precipitation oval with respect to the Weimer convection pattern, especially during times of high activity. The default potential model is still Heelis.

Documentation:

• Updated Users Guide in [html], or [pdf]
• A draft of a model description document is currently under construction, but is not released with this version.
• An improved website for TGCM models is being designed concurrently with this release of TIEGCM. HAO TGCM website