(Bill Sacks, 2019-04-25)

Adding years 1980-2018 of the NLDAS2 atmospheric forcings, reformatted
into the datm expected format by Sean Swenson.

Note that we are not putting a creation date on these files, but are
instead using 'v1'. This is because we plan to add more years in the
future, which would have a different creation date; this would violate
the assumption that all forcing files have the same file name pattern.