DSS presents the FNL (Final) Global Analyses on a pair of 2.5x2.5 degree hemispheric grids every twelve hours. These were prepared operationally by NCEP, interpolated from their GFS model. When the model is changed, the dataset will not be reprocessed. For example, one consequence of increasing model resolution, can change otherwise constant fields, such as topography. The NCEP documents About the Global Parallel System and EMC Model Documentation describe the model. Model changes are described here.

The analyses are available on the surface, 16 mandatory levels from 1000mb to 10mb, boundary layer and some sigma layers, tropopause, and a few others. Parameters include surface pressure, sea level pressure, geopotential height, temperature, sea surface temperature, soil temperature, water content of soil, ice cover, water equivalent of snow depth, relative humidity, specific humidity, u- and v-wind components, vertical motion, vorticity, precipitable water, minimum temperature, maximum temperature and land-sea mask

This dataset is in GRIB format. This is a popular dataset with MM5, WRF and RAMS users - see this. The dataset is free, through the DS083.0 data page. MORE