fields are monthly means from base times 0000, 0600, 1200 and 1800 UTC and for monthly means of daily means all for forecast step 6 only;
each value at each level is stored as a field of grid point values, or of spherical harmonic coefficients;
spherical harmonic coefficients are stored as defined by code figure 1 in tables 9 and 10 of FM 92-IX Ext GRIB;
data are stored in FM 92 GRIB using sufficient bits to ensure that the values represented can be retrieved to an accuracy consistent with the analysis method used;
Internal data is represented as spherical harmonics with triangular truncation at wave number 159 (TL159) or as Gaussian data on a Quasi-regular N80 Gaussian grid;

Levels available are:

1000, 925, 850, 775, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10, 7, 5, 3, 2 and 1 hPa;

Fields available are:

divergence, geopotential, ozone mass mixing ratio, potential vorticity, relative humidity, specific humidity, temperature, u- and v-components of horizontal wind, vertical velocity and vorticity (relative) at each level;

ozone mass mixing ratio, potential vorticity and specific humidity are archived as gaussian fields with the rest archived as spherical harmonics.

23.06.2011