This directory points to datasets needed to test transient crops at f10
resolution.

Eventually, this testmods directory can be removed. However, it is needed for
now because we do not have an 1850 surface dataset for crops - see comment 3 in
<http://bugs.cgd.ucar.edu/show_bug.cgi?id=2010>. So, for now, we are pointing to
a year-2000 surface dataset for the transient run. This is a perfectly
acceptable thing to do, but making it work out-of-the-box would require
introducing some ugly one-off logic that I wanted to avoid.
