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Table of Contents

Below is a list of all agreed upon parameters. Participating Centres are expected to produce output fields in GRIB2 data format and with consistent units. All units are defined by the WMO in the GRIB2 manual. For more information please refer to Guide to the WMO Table Driven Code Form.

For the actual availability of UERRA parameters from each model in MARS refer to the page Parameter availability.

Model level parameters

Output of analyses on (hybrid) model levels are stored up to a height of about 15km every six hours (at 00/06/12/18UTC).

Model level increases with height for MO and decreases for other models.

COSMO: 1..40
HARMONIE: 1..65
MO: 1..63

Name	Abbreviation	Unit
Cloud cover

(model level)

ccl

cc

	%
Pressure	pres	Pa
Specific cloud liquid water content

(model level)

clwc

kg kg

**

^-1
Specific cloud ice water content	ciwc	kg kg

**

^-1

Pressure (model level)presPa

Specific humidity	q	kg kg^-1
Temperature

(model level)

	t	K
U-velocity

(model level)

	u	m s^-1
V-velocity

(model level)

v

m s^-1

Pressure level parameters

Output of forecasts and analyses on pressure levels for defined time steps.

Pressure levels [hPa]:

1000, 975, 950, 925, 900, 875, 850, 825, 800, 750, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 20, 10

...

● Store analysis output in six hourly intervals intervals (at 00 UTC, /06 UTC, 12 UTC, 18 UTC /12/18UTC) for the Unified Model and Harmonie

...

● T+1,2,3,4,5,6 started at 06 UTC and 18 UTC

Name	Abbreviation	Unit
Cloud cover

cc

ccl	%
~~Geopotential height~~	gh	~~gpm~~
Geopotential	z	m² s^-2
Specific cloud liquid water content

(model level)

clwc

kg kg

**

^-1
Specific cloud ice water content	ciwc	kg kg

**

^-1

Pressure (model level)presPa Specific

Relative humidity

q

r

%

kg kg^-1

Temperature

(model level)

	t	K
U-velocity

(model level)

	u	m s^-1
V-velocity

(model level)

v

m s^-1

...

Height level parameters

Output of forecasts and analyses on pressure levels for defined time steps.

Height levels [m]:

15, 30, 50, 75, 100, 150, 200, 250, 300, 400, 500

Time steps:

Analysis:

● Store analysis output in six hourly intervals (at 00/06/12/18UTC) for the Unified Model and Harmonie

● Store analysis output in hourly intervals for COSMO

Forecasts for all models:

● T+1,2,3,4,5,6,9,12,15,18,21,24,27,30 started at 00 UTC and 12 UTC

● T+1,2,3,4,5,6 started at 06 UTC and 18 UTC

...

Name

Abbreviation

Unit

FrequencyPotential vorticitypvK m² kg^-1 s^-1Instantaneous once a day (00Z)

Single-level parameters

The following parameters are available on single levels

NameAbbreviationUnitFrequency10 metre u-velocity10um s^-1Instantaneous once a day (00Z)10 metre v-velocity10vm s^-1Instantaneous once a day (00Z)CAPEcapeJ kg^-1Daily averagedSkin temperaturesktKDaily averagedSnow depth water equivalentsdkg m^-2Daily averaged Snow density
rsnkg m^-3Daily averagedSnow fall water equivalentsfkg m^-2

Accumulated, archived every 24 hours

Snow albedo
asn%Daily averaged Soil moisture top 20cm sm20
kg m^-3 Daily averaged Soil moisture top 100 cm sm100kg m^-3 Daily averaged Soil temperature top 20 cm st20KDaily averaged Soil temperature top 100 cm st100KDaily averagedSurface air maximum temperaturemx2t6K6-hourly
Surface air minimum temperaturemn2t6K6-hourly
Surface air temperature2tKDaily averaged Surface air dewpoint temperature 2d2dDaily averaged Sea surface temperature
wtmpKDaily averaged Sea ice cover ciproportionDaily averagedSurface pressurespPaInstantaneous once a day (00Z)Time-integrated top net thermal radiationttrW m^-2 sAccumulated, archived every 24 hoursTime-integrated surface latent heat fluxslhfW m^-2 sAccumulated, archived every 24 hours


Cloud cover	ccl	%
Pressure	pres	Pa
Specific cloud liquid water content	clwc	kg kg^-1
Specific cloud ice water content	ciwc	kg kg^-1
Relative humidity	r	%
Temperature	t	K
Wind speed	ws	m s^-1
Wind direction	wdir	degree true

Surface level parameters

Time steps:

Analysis:

● Store analysis output in six hourly intervals (at 00/06/12/18UTC) for the Unified Model, Harmonie, MESCAN-SURFEX

● Store precipitation analysis (24 h accumulation from 06 UTC to 06 UTC of next day) output at 06TC for MESCAN-SURFEX

● Store hourly analysis output for COSMO, MESAN

Forecast:

● Store forecast output at T+1,2,3,4,5,6,9,12,15,18,21,24,27,30 started at 00 UTC and 12 UTC for the Unified Model, COSMO

● Store forecast output at T+1,2,3,4,5,6 started at 06 UTC and 18 UTC for the Unified Model, COSMO

● For Harmonie (started at 00/06/12/18UTC):

- - Store sd, sr, al, rsn, slhf, sshf parameters (derived from ALADIN model driving SURFEX) at T+1,2,3,4,5,6 only
  - Store all other parameters at T+1,2,3,4,5,6,9,12,15,18,21,24,27,30

● For MESCAN-SURFEX (started at 00/06/12/18UTC):

- - Store parameters sp,tp,2r,2t,10si,10wdir, tidirswrf from forecast output at T+6 only (fields from ALADIN model driving SURFEX)
  - Store all other parameters from forecast output at T+1,2,3,4,5,6

Info

title	Static fields

Static fields are archived only as of the analysis type. For users' convenience, even they are invariant fields, they should be archived for all analysis output times. In case of ensemble products they should be archived with all ensemble members (again as of the analysis type only).

The surface roughness could be either static or changing parameter depending on model and should be handled accordingly as a static or a prognostic model field.

Precipitation and humidity
Name	Abbreviation	Unit
Percolation	perc	kg m^-2
Surface air relative humidity	2r	%
Surface runoff	sro	kg m^-2
Total column water vapour	tciwv	kg m^-2
Total precipitation	tp	kg m^-2
Accumulated radiation fluxes
Albedo	al	%
Evaporation	eva	kg m^-2
Time-integrated surface latent heat flux	slhf	W m^-2 s
Time-integrated surface sensible heat flux	sshf	W m^-2 s
Time-integrated surface clear-sky solar radiation downwards	adswrf_cs	W m^-2 s
Time-integrated surface clear-sky solar radiation upwards	auswrf_cs	W m^-2 s
Time-integrated surface direct solar radiation	tidirswrf	W m^-2 s
Time-integrated surface net solar radiation	ssr	W m^-2 s

Accumulated, archived every 24 hours

Time-integrated surface

net thermal

solar radiation downwards

str

ssrd

W m^-2 s

Accumulated, archived every 24 hours

Time-integrated surface

sensible heat fluxsshf

clear-sky thermal radiation downwards

adlwrf_cs

W m^-2 s

Accumulated, archived every 24 hours

Time-integrated surface

solar

net thermal radiation

downwards

ssrd

str

W m^-2 s

Accumulated, archived every 24 hours

Temperature and wind speed

Time-integrated surface thermal radiation downwards	strd	W m^-2 s
10 metre wind speed	10si	m s^-1
10 metre wind direction	10wdir	degree true
10 metre wind gust since previous post-processing	10fg	m s

Pressure/Height
^-1
Surface air maximum temperature since previous post-processing	mx2t	K
Surface air minimum temperature since previous post-processing	mn2t	K
Surface air temperature	2t	K
Skin temperature	skt	K
Mean sea level pressure	msl	Pa
Surface pressure	sp	Pa
Cloud properties
High cloud cover	hcc	%
Low cloud cover	lcc	%
Medium cloud cover	mcc	%

Accumulated, archived every 24 hours


Total cloud cover	tcc	%

Daily averaged Total column water tcw

Snow
Snow density	rsn	kg m^-

2Daily averaged Total precipitation

³
Snow depth	sde	m
Snow depth water equivalent	sd

tp

kg m^-2

Accumulated, ~~archived every 24 hours~~ 6-hourly Convective precipitation *
cp

Snow fall water equivalent

sf

kg m^-2

Accumulated, archived every 24 hours Northward turbulent surface stress *
nsssN m^-2 sAccumulated, archived every 24 hours Eastward turbulent surface stress * ewssN m^-2 sAccumulated, archived every 24 hours Mean sea-level pressure mslPaInstantaneous once a day (00Z)Water runoff and drainage *
rokg m^-2 Accumulated, archived every 24 hours Surface water runoff *
srokg m^-2 Accumulated, archived every 24 hoursLand sea masklsmProportion of land

Instantaneous once a day (00Z)

Only control forecast

Orographyoroggpm

Instantaneous once a day (00Z)

Only control forecast

Soil type sltCategorical

Instantaneous once a day (00Z)

Only control forecast

Static fields
Soil
Soil heat flux	sohf	W m^-2
Land-sea mask	lsm	(0-1)
Orography	orog	gpm
Surface roughness	sr	m

Soil level parameters

Time steps: the same as surface level parameters

Soil levels: parameters should be provided on original model levels or layers

COSMO: 8 soil layers
level borders at 0, 0.01, 0.03, 0.09, 0.27, 0.81, 2.43, 7.29, 21.87 m
HARMONIE: 3 soil levels/layers (sot on levels, vsw on layers)
level depths are grid dependent
MESCAN-SURFEX: 14 soil layers (only 6 layers for preliminary shorter re-analysis runs)
level borders at 0, 0.01, 0.04, 0.1, 0.2, 0.4, 0.6 m
MO: 4 soil layers
level borders at 0, 0.1, 0.35, 1 and 3 m

Info

title	Soil depth

The soil depth could be either a constant or a grid dependent parameter depending on given model soil scheme.

If constant, the soil depths should be mentioned only in documentation of given model.

If grid dependent it should be archived the same as other static fields for all analysis output times. In case of ensemble products it should be archived with all ensemble members (again as of the analysis type only).

Soil	Abbreviation	Unit
Liquid non-frozen volumetric soil water	liqvsm	m³ m^-3
Soil temperature	sot	K
Soil depth	sod	m
Volumetric field capacity	voltso	m³ m^-3
Volumetric soil water	vsw	m³ m^-3
Volumetric wilting point	vwiltm	m³ m^-3

Additional information and links

UERRA parameters
UERRA parameters (life document on google drive)
GRIB-API parameter database
how is soil moisture defined for TIGGE
example of soil layers in MARS
description of multi-layer definition in MARS
radiation in MARS
latest WMO documentation on GRIB2 tables (normally it is under 1st link returned by google for "WMO latest")

Attached documents to this page which were used for creation of GRIB2 UERRA definitions (they are linked above too):

radiation_in_mars.pdf (to understand the radiation fluxes)
Parameter_table_20150427.docx (the latest official version of agreed upon UERRA parameters)

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Key

Model level parameters

Pressure level parameters

Height level parameters

Surface level parameters

Precipitation and humidity

Accumulated radiation fluxes

Temperature and wind speed

Pressure/Height

Cloud properties

Snow

Soil

Static fields

Soil level parameters

Soil

Additional information and links