[tgcmgroup] TIE-GCM auroral control parameters

[Stan Solomon]

The hierarchy of auroral control parameters in the TIE-GCM is somewhat 
confusing, because there are so many options.

First of all, there is a switch called POTENTIAL_MODEL which can be set 
to either "HEELIS" (the default) or "WEIMER".

In either case, the model may then be run with namelist input parameters 
specifying the inputs to the potential model, or with time-dependent 
parameters read from a file.

For Heelis runs: the model will use the cross-tail potential CTPOTEN and 
hemispheric power POWER specified in the namelist inputs, if present. 
Alternatively, it can use KP specified in the namelist inputs, from 
which CTPOTEN and POWER are calculated using correlation relationships. 
  These can also be time-dependent arrays in the namelist inputs.  If 
CTPOTEN, POWER, and KP are *not* present, the model reads a geophysical 
index file, specified by GPI_NCFILE, from which it gets time-dependent 
3-hour KP.  A GPI file covering 1960-2015 is provided with the model 
download.

For Weimer runs: the model will use interplanetary magnetic field and 
solar wind parameters BYIMF, BZIMF, SWDEN, and SWVEL specified by the 
namelist inputs.  If these are not present, it will read them from a 
file specified by IMF_FILE.  A GPI file can also specified for Weimer 
runs, but only for solar irradiance inputs.  Selected 1-year IMF files 
are provided with the model download, and others are available at 
http://download.hao.ucar.edu/pub/tgcm/.

Solar irradiance input control is similar.  The model uses F107 and 
F107A if specified in the namelist inputs, and otherwise gets them from 
the GPI file.  It is possible to mix solar and auroral inputs between 
namelist and file-based, for instance, you could run with time-dependent 
KP from the GPI file but constant F10.7 and F10.7 from namelist inputs.

So, if you're trying to do a "Heelis/GPI" run, or a "Weimer/IMF" run (in 
our vernacular), don't set namelist inputs because they will override 
the file-based inputs.  For more details, see chapter 5 of the user 
guide, and the extensive comment in subroutine inp_solar in file input.F.

Stan


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...a user writes...

> 1) I ran the job for "tiegcm_dec2006_weimer_imf.inp" with only the Kp=
> 4 and F10.7 = 180 and average F10.7=180.
> 2) Also another run with Kp = 8 and F10.7 = 180 and average F10.7=180.
> In both runs GPI and IMF files were NOT commented out.
> Density maps for original (default), Kp=4 and Kp=8 all looked the same
> for all 30 days.
>
> Is it because the model reverts immediately back to realistic
> conditions?  or because I used the static KP and not KP_TIME?