Efforts have been made in the past to produce consistent sets of
wave data that could be used to establish the wave climatology at
different locations and to obtain assessments of the expected extreme
values and of long-term trends. An important study was made by
NCEP, which produced a large data set of global atmospheric data
resulting from a reanalysis of previous data with a consistent procedure.
This important data set was used as the input forcing for various
other hindcast studies.