Parameters

S2S parameters are encoded in the WMO compliant GRIB2 format.

for full information about GRIB2 format refer to Guide to the WMO Table Driven Code Form
for full details of TIGGE GRIB2 encoding refer to Instructions
for list of parameters provided by each centre refer to Provided parameters

List of parameters

The following parameters are available on ten pressure levels (1000, 925, 850, 700, 500, 300, 200, 100, 50 and 10 hPa)

Name	Abbreviation	Unit	Frequency
Geopotential height	gh	gpm	Once a day at 0Z (with control forecast only)
Temperature	t	K	Once a day at 0Z (with control forecast only)
U-component of wind	u	m s^-1	Once a day at 0Z (with control forecast only)
V-component of wind	v	m s^-1	Once a day at 0Z (with control forecast only)
Vertical velocity	w	pa s^-1	Once a day at 0Z (with control forecast only)

The following parameters are available on seven pressure levels (1000, 925, 850, 700, 500, 300 and 200 hPa)

Name	Abbreviation	Unit	Frequency
Specific humidity	q	kg kg^-1	Once a day at 0Z (with control forecast only)

Potential temperature level parameters

The following parameters are available on one potential temperature level (320 K)

Name	Abbreviation	Unit	Frequency
Potential vorticity	pv	K m² kg^-1 s^-1	Once a day at 0Z (with control forecast only)

The following parameters are available on single level.

Computation of daily average depends on the model:
- either direct model output
- or computed from instantaneous values at 0, 6, 12 and 18Z

	Name	Abbreviation	Unit	Frequency
1	2 m temperature	2t	K	Daily averaged
2	2 m dewpoint temperature	2d	2d	Daily averaged
3	10 m u-component of wind	10u	m s^-1	6-hourly
4	10 m v-component of wind	10v	m s^-1	6-hourly
5	Convective available potential energy (CAPE)	cape	J kg^-1	Daily averaged
6	Maximum 2 m temperature in the last 6 hours	mx2t6	K	6-hourly
7	Minimum 2 m temperature in the last 6 hours	mn2t6	K	6-hourly
8	Skin temperature	skt	K	Daily averaged
9	Snow depth water equivalent	sd	kg m^-2	Daily averaged
10	Snow density	rsn	kg m^-3	Daily averaged
11	Snow albedo	asn	%	Daily averaged
12	Soil moisture top 20 cm	sm20	kg m^-3	Daily averaged
13	Soil moisture top 100 cm	sm100	kg m^-3	Daily averaged
14	Soil temperature top 20 cm	st20	K	Daily averaged
15	Soil temperature top 100 cm	st100	K	Daily averaged
16	Sea ice area fraction	ci	proportion	Daily averaged
17	Sea surface temperature	wtmp	K	Daily averaged
18	Total cloud cover	tcc	%	Daily averaged
19	Total column water	tcw	kg m^_-2	Daily averaged

	Name	Abbreviation	Unit	Frequency
1	Mean sea-level pressure	msl	Pa	Once a day
2	Land-sea mask	lsm	Proportion of land	Once a day
3	Orography	orog	gpm	Once a day
4	Soil type	slt	Categorical	Once a day
5	Surface pressure	sp	Pa	Once a day

	Name	Abbreviation	Unit	Frequency
1	Surface sensible heat flux	sshf	W m^-2 s	24-hourly
2	Surface latent heat flux	slhf	W m^-2 s	24-hourly
3	Surface net solar radiation	ssr	W m^-2 s	24-hourly
4	Surface solar radiation downwards	ssrd	W m^-2 s	24-hourly
5	Top net thermal radiation	ttr	W m^-2 s	24-hourly
6	Surface net thermal radiation	str	W m^-2 s	24-hourly
7	Surface thermal radiation downwards	strd	W m^-2 s	24-hourly
8	Total precipitation	tp	kg m^-2	6-hourly
9	Convective precipitation	cp	kg m^-2	24-hourly
10	Snow fall water equivalent	sf	kg m^-2	24-hourly
11	Eastward turbulent surface stress	ewss	N m^-2 s	24-hourly
12	Northward turbulent surface stress	nsss	N m^-2 s	24-hourly
13	Water runoff and drainage	ro	kg m^-2	24-hourly
14	Surface water runoff	sro	kg m^-2	24-hourly

The following parameters coming from ocean part of modelling system are available on single level.

Computation of daily average depends on the model:
- either direct model output
- or computed from instantaneous values at 0, 6, 12 and 18Z

	Name	Abbreviation	Unit	Frequency
1	Depth of 20 C isotherm	t20d	m	Daily averaged
2	Mean sea water practical salinity in the upper 300 m	sav300	psu (numeric)	Daily averaged
3	Mean sea water potential temperature in the upper 300 m	mswpt300	K	Daily averaged
4	Ocean mixed layer thickness defined by sigma theta 0.01 kg/m3	mlotst010	m	Daily averaged
5	U-component of surface current	ocu	m s^-1	Daily averaged
6	V-component of surface current	ocv	m s^-1	Daily averaged
7	Sea ice thickness	sithick	m	Daily averaged
8	Sea surface height	zos	m	Daily averaged
9	Sea surface practical salinity	sos	psu (numeric)	Daily averaged

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