The MSLP climatology used is based on the NCEP2 (National Centers for Environmental Prediction) re-analyses for the period 1979-2000.

The reanalysis is done at NCEP (formerly NMC) using T62 (209 km) global spectral model of 28 vertical levels. This is the same model used in the assimilation system, as implemented in the NCEP operational system in December 1994. The model has 5 levels in the boundary layer and about 7 levels above 100 hPa. The lowest model level is about 5 hPa from the surface, and the top level is at about 3 hPa.

For more information about NCEP see http://www.ncep.noaa.gov/

Last Modified March 2008