A gridded climatological monthly-mean data base of Arctic water vapor characteristics has been assembled by combining fixed station data with data from soundings taken over the Arctic Ocean from ships and Russian drifting stations. Variables provided include temperature, specific humidity, zonal vapor flux, meridional vapor flux, zonal wind speed, and meridional wind speed, available for 15 pressure levels extending from the surface (1,000 mb) to 300 mb. Sea level pressure and geopotential height are provided for the 850 mb, 700 mb, 500 mb and 300 mb levels. Precipitable water, vertically integrated zonal vapor flux and vertically integrated meridional vapor flux are available for five layers: surface to 850 mb, 850 to 700 mb, 700 to 500 mb, 500 to 400 mb and 400 to 300 mb. Coverage of the rawinsonde archives extends from 1954 through 1990 for data from the Russian North Pole series of drifting ice stations over the Arctic Ocean; from 1976 through 1991 for fixed-station data obtained from the National Center for Atmospheric Research; and from about 1958 through 1991 for fixed-station data obtained from the Historical Arctic Rawinsonde Archive. All variables were obtained through interpolation of the raw sounding data, with the exception of sea level pressure and geopotential height. The files are structured in monthly data arrays over a subsection of the National Meteorological Center grid (octagonal grid format) centered over the pole, extending to approximately 65 degrees North on each side and about 55 degrees North at the corners.