The monthly means of NCEP/NCAR Reanalysis (R1) products, archived in ds090.0 dataset, are extracted and reorganized into 10 subgroups in this dataset. The 10 subgroups are: dgn, presA, presB, theta, xprod, 00Z, 06Z, 12Z, 18Z and rest subgroups. The monthly means of diagnostic terms, (such as various heating terms, convective moistening rate, etc.) are in the dgn subgroup. The presA subgroup contains most commonly used parameters, like geopotential height, temperature, U and V winds, relative humidity, at all 17 pressure levels. The presB subgroup has the remaining variables on pressure levels. The theta subgroup includes all variables on isentropic levels. The xprod contains cross products of variables at pressure levels. The 00Z, 06Z, 12Z and 18Z subgroups have monthly means computed from those individual hours only. Monthly means of flux terms (like wind at 10m, temperature at 2m, etc) and accumulative variables (like precipitation rate, precipitable water, etc.) are in the rest subgroup.

The data files are in WMO GRIB format. Both the monthly means and their variances are in the same file but in different GRIB records. Examples of separating monthly means from variances are shown in how2use_grads.txt.

All subgroups will be available on line under data. The ones that are not on line yet will be moved over upon request.