EPS forecasts are ran at TL639 resolution at 62 levels up to day 10 and with grid point data being generated on reduced Gaussian grid N320. EPS forecasts are ran at TL319 resolution at 62 levels from time step 246 to day 15 with grid point data being on reduced Gaussian grid N160s. In addition, two calibration/validation forecasts are ran, one at T639 L62 (forecast NUMBER=1) and the other at T319 L62 (forecast NUMBER=2). Data is post-processed every 3 hours to time step 144 and 6 or 12 hourly to day 15 (depending on a parameter). Step 0 is included. Parameters available in dissemination are listed in the Table 5.1 below.

Flux fields are quantities accumulated since the beginning of the forecast, e.g. all precipitation and snowfall parameters. Reducing the resolution of the model at step T+240 requires interpolation between Gaussian grids used in leg 1 (N320) and leg 2 (N160). As a consequence, noise will appear in flux fields when taking differences in time for timestep intervals starting from T+240 or spanning T+240, e.g. precipitation for the interval T+(252-240) or T+(246-234).

To limit unnecessary impact from interpolation on the consistency of the fields, users wishing to extend their applications to day 15 are advised as follows:

1. Applications requiring products starting from or spanning step T+240 users should specify the keyword GAUSSIAN = REDUCED, GRID = 160 in the dissemination request. This will provide the user with all fields on the original model grid of VarEPS leg 2.

2. For applications requiring products starting from or spanning step T+240 users wishing to obtain products interpolated to regular lat/lon grids are advised to have the products from leg 1 truncated to the N160 grid prior to interpolation to their choice of lat/lon grid. This can be achieved by specifying an additional key word, e.g. RESOL = REDUCED GAUSSIAN 128, GRID = 0.5/0.5 in the dissemination requests. This new feature of requesting the truncation of Gaussian grids prior to further interpolation to regular grids will also become available in MARS.

3. New applications only using data starting from step T+246 will not be affected by interpolation problems described above.

Model levels, pressure levels and surface products

Horizontal resolution

- 0.25 x 0.25 degrees latitude-longitude grid, or multiples thereof (leg 1)

- 0.5 x 0.5 degrees latitude-longitude grid, or multiples thereof (leg 2)

- spectral truncation appropriate to the forecast model in use.

- the Gaussian grid appropriate to the forecast model in use. The following Gaussian grid numbers are supported: 320, 200, 160, 128, 80, 48 and 32 (200 and 160 only for leg 1 data).

- any sub-area

Vertical resolution

- pressure levels (depending on the specific parameter and the forecast time step): 1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10,7,5,3,2,1 hPa;

- model levels: currently 62 hybrid coordinate level.

Verifying times

-T+0 to T+144 at 3 hour intervals and T+150 to T+360 at 6 hour intervals;

- Upper air parameters on model levels as well as parameters on `potential temperature' level for perturbed forecast, T+0 to T+144 at 3 hour intervals and T+150 to T+168 (inclusive) at 6 hour intervals;

* Orography field is defined as parameter Z on model level 1 + Control forecast only
Table 5.1 Control and Perturbed forecast products

FIELD CODE	MARS ABBREV.	FIELD NAME	UNITS	NO. OF BITS/VAL.
3	PT	Potential Temperature	K	16
33	RSN	Snow Density	kg m**-3	16
39	SWVL1	Volumetric Soil Water layer 1	m3m-3	12
40	SWVL2	Volumetric Soil Water layer 2	m3m-3	12
41	SWVL3	Volumetric Soil Water layer 3	m3m-3	12
42	SWVL4	Volumetric Soil Water layer 4	m3m-3	12
49	10FG	Wind gust at 10 meters	m/s	16
54	PRES	Pressure	Pa	16
59	CAPE	Convective available potential energy	JKg-1	16
60	PV	Potential Vorticity +	m2s-1Kkg-1	16
121	MX2T6	Max. temp. at 2m in the past 6hours	K	12
122	MN2T6	Min. temp. at 2m in the past 6hours	K	12
123	10FG6	Wind gust at 10m in the past 6hours	m/s	16
129	Z	Geopotential*	m2s-2	16
130	T	Temperature	K	12
131	U	U-velocity	m/s	12
132	V	V-velocity	m/s	12
133	Q	Specific humidity	kg/kg	12
135	W	Vertical velocity	Pa/s	16
138	VO	Vorticity	s-1	16
139	STL1	Soil Temperature Level 1	K	12
141	SD	Snow depth	m	12
142	LSP	Large scale precipitation	m	16
143	CP	Convective precipitation	m	16
144	SF	Snow fall	m	16
145	BLD	Boundary Layer Dissipation
146	SSHF	Surface sensible heat flux ++	Wm-2s	12
147	SLHF	Surface latent heat flux	Wm-2s	12
151	MSL	Mean sea level pressure	Pa	12
152	LNSP	Log surface pressure	-	12
155	D	Divergence	s-1	16
157	R	Relative humidity	-	8
159	BLH	Boundary Layer Height	m	16
164	TCC	Total cloud cover	(0-1)	8
165	10U	10 metre U	m/s	12
166	10V	10 metre V	m/s	12
167	2T	2 metre temperature	K	12
168	2D	2 metre dewpoint temperature	K	12
169	SSRD	Surface solar radiation downwards	W m**-2 s	16
170	STL2	Soil Temperature Level 2	K	12
172	LSM	Land/sea mask +	(0,1)	8
176	SSR	Surface Solar Radiation	W m**-2 s	16
177	STR	Surface Thermal Radiation	W m**-2 s	16
178	TSR	Top Solar Radiation	W m**-2 s	16
179	TTR	Top Thermal Radiation	W m**-2 s	16
180	EWSS	U-stress*	Nm**-2	12
181	NSSS	V-stress*	Nm**-2	12
182	E	Evaporation	m of water	16
183	STL3	Soil Temperature Level 3	K	12
189	SUND	Sunshine duration	s	16
197	GWD	Gravity Wave Dissipation	W m**-2 s	16
198	SRC	Skin reservoir content	m (ofwater)	12
201	MX2T	Max. temp. at 2m since prev. post-processing	K	12
202	MN2T	Min. temp. at 2m since prev. post-processing	K	12
228	TP	Total precipitation	m	16
235	SKT	Skin temperature	K	12
236	STL4	Soil Temperature Level 4	K	12
238	TSN	Temperature of snow layer	K	16
246	CLWC	Cloud liquid water content	Kg/Kg	12
247	CIWC	Cloud ice water content	Kg/Kg	12
246.228	100U	100 metre U wind component	m/s	16
247.228	100V	100 metre V wind component	m/s	16

Potential temperature and potential vorticity levels

Potential Vorticity level products (Table 5.1) are available on 3 hour intervals 0-144 and 6 hour intervals 150 to 360 and on the level 2000 as:

- control, perturbed and calibration/validation forecast products, parameters PT,

PRES, Z, U, V and Q;

Potential Temperature (Isentropic) level products (Table 5.1) are available on 3 hour intervals 0-144 and 6 hour intervals 150 to 168 as:

- control, perturbed and calibration/validation forecast products, parameters PV,

PRES, VO and D, levels 300, 315, 330, 350,370, 395, 475, 600 and 850;

Control, Perturbed and Calibration/Validation forecast requirements

The following command language parameters are specific for the control and perturbed forecast requirements. Other DIS parameters are listed under the general EPS requirements above.

TYPE

CONTROL FORECAST

PERTURBED FORECAST

CALIBRATION VALIDATION

[CF]

[PF]

[CV]

DOMAIN

GLOBAL

[G]

(default)

NUMBER

n-ENSEMBLE NUMBER

[1-50]

off

[1-2]

(for TYPE=PF)

(for TYPE=CF)

(for TYPE=CV)

LEVTYPE

PRESSURE LEVEL

POTENTIAL VORTICITY

POTENTIAL TEMPERATURE ]

[PL]

[PV]

[PT]

LEVELIST

* (value of pressure)

1000/850/700/500/200

NB ALL is not permitted

(See 5.4.2 for LEVTYPE=PT/PV products);

(1 - 62 for LEVTYPE=ML)

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 or multiples thereof (leg 1);

0.5/0.5 or multiples thereof (leg 2);

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 (320 and 200 only for leg 1 data);

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

STEP

* (hours)

l gives forecast time step(s);

00/TO/144/BY/3

150/TO/360/by/6

(Dissemination requirements validation tool provides detailed log on the

availability of each specific product)

NB ALL, is not permitted.

PARAM

Field name abbreviation

NB ALL is not permitted.

Available parameters are listed in the Table 5.1.

GRIB section 1 definition for Control, Perturbed and Calibration/Validation forecast products

By convention, ECMWF always uses octet 41 to define which set of local definitions follow. The set of local definitions for EPS Control and Perturbed forecast fields:

Table 5.2 GRIB section 1 definition for Control and Perturbed forecast products

Octet

Ksec1 element

Contents

ECMWF local GRIB use definition identifier.

30 = Ensemble forecast data.

Class:

1 = Operations

Type:

10 = Control forecast

11 = Perturbed forecast

44-45

46-49

Stream:

1035 = Ensemble forecasts

Version number or experiment identifier.

(4 ASCII characters, right justified)

Number:

Set to 0 for MARS labelling (simple labelling)

When element 40 = 1035, this is the ensemble forecast number.

When element 39 = 10, this is the control forecast number and is set to 0.

The total number of forecasts in an ensemble; the

number includes the control forecast.

Ocean Atmosphere Coupling

Reserved . Set to 0.

54-55

56-59

60-61

Padding

Leg base Date (in format YYYYMMDD)

Leg base Time (in format hhmm)

63-66

Leg Number

Reserved . Set to 0.

67-70

71-74

75-106

Climate date - from (YYYYMMDD)

Climate date - to (YYYYMMDD)

Reserved . Set to 0.

18-01-2011