========================================================================
Notes about how the
UGRID_1km-merge-10min_HYDRO1K-merge-nomask_c130402.nc file was
created, and how mapping files were created from it

Bill Sacks
April 3, 2013
========================================================================

------------------------------------------------------------------------
Creating the ugrid file
------------------------------------------------------------------------

Sean Swenson first created a scrip grid file:
SCRIPgrid_1km-merge-10min_HYDRO1K-merge-nomask_c130402.nc

(Note that this is an unstructured grid file which merges grids from
two sources: (1) 1km HYDRO1K data, and (2) 10min USGS data that has no
mask.)

I then ran two utilities provided by Peggy Li (on the ESMF team):
Scrip2ESMF and esmf2ugrid. (See </glade/p/work/sacks/scrip2ugrid>;
much of what is there was copied from </glade/u/home/peggyl/bin>.)
(Scrip2ESMF takes about 3 hours to run; esmf2ugrid is very fast.)

This created the ugrid file:
UGRID_1km-merge-10min_HYDRO1K-merge-nomask_c130402.nc

------------------------------------------------------------------------
Creating mapping files
------------------------------------------------------------------------

NOTE: I will soon be introducing functionality into mkmapdata.sh to be
able to create mapping files from this high-resolution UGRID
file. However, here I document the procedure I needed to use before
this functionality was in place.


To create mapping files from the above grid file, a recent beta
version of the ESMF mapping utility is needed, which supports
"--netcdf4". In addition, other differences are required compared to
the standard options in mkmapdata.sh. Thus, I performed this
regridding using my own scripts: master_script_regional.sh and
master_script_global.sh (and its variations) in
/glade/p/work/sacks/cesm_misc/make_mapping_files/land1km_ugrid (also
here:
https://svn-user-sacks.cgd.ucar.edu/cesm_misc/make_mapping_files/trunk/land1km_ugrid).

The command used in these scripts was:

mpirun.lsf /glade/u/home/peggyl/bin/ESMF_RegridWeightGen -s $source_gridfile -d $dest_gridfile -w $mapname -m conserve --src_type UGRID --src_meshname landmesh -i --netcdf4

To obtain the resolutions and destination grid files, I used the
namelist defaults from clm4_0_68.