period supported - 18 July 2000 to current date;
each parameter at each level is stored as a field either 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;
More information about isentropic levels

The changes to this data set are as follows:

18 July 2000

Internal data is represented as spherical harmonics with triangular truncation at wave number 511 (T511);

Data consists of daily 10 day forecasts from base times 0000 and 1200 UTC;

Forecast steps available are 3 hourly to HH+72 and then 6 hourly to HH+240;

9 isentropic surfaces, 300, 315, 330, 350, 370, 395, 475, 600, 850 K;

Fields available are divergence, potential vorticity, pressure, u- and v-components of horizontal wind and relative vorticity;

Potential vorticity is archived on a Gaussian grid at N256 resolution.

1 February 2006

Internal data representation is in spherical harmonics with triangular truncation at wave number 799 (TL799). Gaussian fields are represented on an N400 Quasi-regular Gaussian grid (400 lines between the pole and the equator, with varying number of points along each row)

Order forms :

If you wish to make an order from this data set please download the following two Acrobat (PDF) files :

1. Instructions and Standard Order forms (common for all data sets):

24 KB

2. Data Set Order form (to select data from this specific data set only) :

8 KB

26.01.2006