The dissemination of EPS field products is controlled in a similar manner to the dissemination of data from ECMWF's medium-range forecasting system. Dissemination requirements for EPS field products are added to the general set of dissemination requirements for each Member State - it is not necessary to update and maintain separate sets of requirements for products required from the EPS.

The rules for requesting dissemination products from ECMWF apply also to EPS field products. Member States can maintain their own dissemination requirements using web facility (https://msaccess.ecmwf.int:9443/do/product/requirements/); Also Member States may request ECMWF to make changes on their behalf. Requests for ECMWF to make changes to requirements should be addressed in writing or by computer mail from the Member State's TAC representative to the Head of Operations at ECMWF, or to the Head of the "Data and Services Section", who is authorised by the Head of Operations to act on his behalf with respect to such changes.

Dissemination requirements are presented by means of the command language. This language has been designed to conform, where possible, to the MARS command language.

The following command language parameters are common for all EPS requirements:

Identification parameters

STREAM

ENSEMBLE FORECAST

[EF]

Target parameters

TARGET

"destination:dissemination_stream_name"

- destination is a three character destination name;

- dissemination_stream_name is a two character dissemination stream name

(the list of destinations/streams is published on:

https://msaccess.ecmwf.int:9443/do/product/requirements/)

PRIORITY

1 - 99

Indicates the transmission priority of a `dissemination stream'.

(value 1 being the highest and value 99 being the lowest transmission priority);

Date and time parameters

TIME

12/00

Gives products base time.

Meteorological parameters

PARAM

Field name abbreviation

NB ALL is not permitted.

Available parameters are listed in each products sub-set table.

Data processing parameters

RESOL

[AV]

(default 639 for leg 1)

(default 319 for leg 2)

* Positive integer giving the spectral triangular truncation.

(e.g. 10 indicates T10 filtered products required. May only be used with multi-level (i.e. upper air) parameters. May also be used if spectral products are required.)

REDUCED GAUSSIAN 160

Will result in converting original model field into reduced Gaussian grid

N160 before interpolating into requested latitude-longitude grid. Valid only when requesting latitude-longitude grids.

OFF

FORMAT

GRIB

[GB]

GAUSSIAN

REGULAR

REDUCED

OFF

Indicating Gaussian grid type. Gaussian grid resolution is given by the GRID parameter.

GRID

*/*

AUTOMATIC [AUTO]

If the form a/b is used, a latitude-longitude grid is defined, where:

a= grid resolution (deg.) along a latitude line (i.e. East/West)

b= grid resolution (deg.) along a longitude line (i.e. North/South)

0.25/0.25 (leg1) or multiples thereof; (TYPE=CF/PF/CV/EP only);

0.5/0.5 (leg2) or multiples thereof (TYPE=CF/PF/CV/EP only);

Note that it is possible to specify different values for a and b to generate a quasi-regular grid system with a different resolution in the West-East direction from that in the North-South direction. This feature is only valid for latitude-longitude grid.

If a single positive integer is coded, it is interpreted as Gaussian grid number for grids defined as GAUSSIAN=REDUCED or REGULAR. The following Gaussian grid numbers are supported: 320, 200, 160, 128, 80, 48 and 32.

AUTOMATIC - values for the parameter GRID will be defined automatically based on STREAM/DOMAIN as well as RESOL/ GAUSSIAN parameter values;

AREA

*/*/*/*

Output area definition. Four values (3 decimal places allowed) to provide a user- defined sub-area as North/West/South/East;

Negative values indicate western longitudes and southern latitudes.

ROTATION

OFF to switch off rotation (default)

a/b

a = is the latitude of the southern pole of rotation

b = is the longitude of the southern pole of rotation

FRAME

OFF to switch off the frame option

n is the number of points inward from each edge of defined area required to form a boundary product. The resulting FM 92 GRIB code will contain bits set within the appropriate ate flag to indicate that sections 2 and 3 are both present.

BITMAP

OFF to switch off the bitmap option

"filename"

"filename" is the name of a file containing a valid user-defined bitmap specification to build a product by selecting data from points of a latitude-

longitude or a Gaussian grid.

ACCURACY

NORMAL

ARCHIVED VALUE

[N]

[AV]

(default) - GRIB only

n is the number of bits per packed value. n must not be less than half of default value nor greater then 24.

[N] - Default values are listed in the Table 4.2

[AV] - Resulting field will have accuracy of the originally generated and archived field.

PACKING

ARCHIVED VALUE

SIMPLE

SECOND ORDER

COMPLEX

[AV]

[SIM]

[SO]

[CO]

(default)

AV - GRIB packing as currently in use, at the moment SIMPLE for grid point data and COMPLEX for spherical harmonics data.

SIM - simple packing (both grid point and spherical harmonics data);

SO - grid point data only (substantiality reduces the size of GRIB messages);

CO - spherical harmonics data only;

PADDING

AUTOMATIC

NONE

[AUTO]

[N]

as currently in use (default);

no padding;

n is the number of bytes to which multiple the binary message is padded to with NULL bytes;

The meaning of AUTO is at the moment 120 bytes for GRIB data and 8 bytes for BUFR data. Also, these are the only values supported for n at the moment.

OPTIONS

NORMAL

DELAY

[NORM] (default)

[DELA]

Note:

DELAY causes products to be generated, but not transmitted;

DELAY products can be obtained using the repeat facility.

18-01-2011