Monthly Northern Hemisphere Tropospheric Analyses

Monthly mean grids are available separately for 00Z and 12Z (or 03Z and 15Z in the earlier years). Parameters include temperature, geopotential height, and u- and v- wind components at various tropospheric levels, and sea-level pressure and surface temperature.

The data are presented on a 47-by-51 north polar stereographic grid with a 381 kilometer resolution (at 60N). We continue to update this dataset mainly for users who have used it in the past and wish to continue receiving the same format. Particularly from April 1997 on, the grids in this dataset are derived from NCEP operational outputs that have a better resolution that what is offered here, so please consider those other more-recent datasets especially if your needs are for data from the late 1990s onward.