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Introduction

Here we document the ERA5 dataset, which, eventually, will cover the period January 1950 to near real time (NRT). ERA5 data released so far covers the period from 1979 to 2-3 months before the present.

ERA5 was produced using 4D-Var data assimilation in CY41R2 of ECMWF’s Integrated Forecast System (IFS), with 137 hybrid sigma/pressure (model) levels in the vertical, with the top level at 0.01 hPa. Atmospheric data are available on these levels and they are also interpolated to 37 pressure, 16 potential temperature and 1 potential vorticity level(s). "Surface or single level" data are also available, containing 2D parameters such as precipitation, 2m temperature, top of atmosphere radiation and vertical integrals over the entire atmosphere. The IFS is coupled to a soil model, the parameters of which are also designated as surface parameters, and an ocean wave model.

The ERA5 dataset contains one (31 km) high resolution realisation (HRES) and a reduced resolution ten member ensemble (EDA). Generally, the data are available at a sub-daily and monthly frequency and consist of analyses and short (18 hour) forecasts, initialised twice daily from analyses at 06 and 18 UTC. Most analysed parameters are also available from the forecasts. There are a number of forecast parameters, e.g. mean rates and accumulations, that are not available from the analyses.

How to download ERA5

The data are archived in the ECMWF data archive (MARS) and a pertinent sub-set of the data, interpolated to a regular latitude/longitude grid, has been copied to the Climate Data Store (CDS) disks.

Documentation is available on how to download ERA5 data. (Member State users can access the data directly from MARS, in the usual manner.) Data can be downloaded either from the relevant CDS download page or, for larger data volumes, using the CDS API.

The IFS and data assimilation

The model documentation for CY41R2 is at https://www.ecmwf.int/en/publications/search/?solrsort=sort_label%20asc&secondary_title=%22IFS%20Documentation%20CY41R2%22

The 4D-Var data assimilation uses 12 hour windows from 09 UTC to 21 UTC and 21 UTC to 09 UTC (the following day).

The model time step is 12 minutes for the HRES and 20 minutes for the EDA, though occasionally these numbers are adjusted to cope with instabilities.

Data organisation

The data can be accessed from MARS using the keywords class=ea and expver=0001. Subdivisions of the data are labelled using stream, type and levtype.

Stream:

  • oper: HRES sub-daily
  • wave: HRES waves sub-daily
  • mnth: HRES synoptic monthly means
  • moda: HRES monthly means of daily means
  • wamo: HRES waves synoptic monthly means
  • wamd: HRES waves monthly means of daily means
  • enda: EDA sub-daily
  • ewda: EDA waves sub-daily
  • edmm: EDA synoptic monthly means
  • edmo: EDA monthly means of daily means
  • ewmm: EDA waves synoptic monthly means
  • ewmo: EDA waves monthly means of daily means

Type:

  • an: analyses
  • fc: forecasts
  • em: ensemble mean
  • es: ensemble standard deviation

Levtype:

  • sfc: surface or single level
  • pl: pressure levels
  • pt: potential temperature levels
  • pv: potential vorticity level
  • ml: model levels


In MARS: the date and time of the data is specified with three MARS keywords, date, time and step. For analyses, step=0 hours so that date and time specify the analysis time. For forecasts, date and time specify the forecast start time and step specifies the number of hours since that start time. The combination of date, time and forecast step defines the validity time. For analyses, the validity time is equal to the analysis time.

In the CDS: analyses are provided rather than forecasts, unless the parameter is only available from the forecasts. The date and time of the data is specified using the validity date/time, so step does not need to be specified. For forecasts, steps between 1 and 12 hours have been used to provide data for all the validity times in 24 hours, see Table 0 below.


Table 0: the mapping, for forecasts, between MARS date, time and step and the CDS date and time

CDS

date  time

MARS

date      time  step


CDS

date  time

MARS

date   time  step

date  00

date-1  18        06


date  12

date   06      06

date  01

date-1  18        07


date  13

date   06      07

date  02

date-1  18        08


date  14

date   06      08

date  03

date-1  18        09


date  15

date   06      09

date  04

date-1  18        10


date  16

date   06      10

date  05

date-1  18        11


date  17

date   06      11

date  06

date-1  18        12


date  18

date   06      12

date  07

date      06        01


date  19

date   18      01

date  08

date      06        02


date  20

date   18      02

date  09

date      06        03


date  21

date   18      03

date  10

date      06        04


date  22

date   18      04

date  11

date      06        05


date  23

date   18      05


Spatial grid

The ERA5 HRES atmospheric data has a resolution of 31km, 0.28125 degrees, and the EDA has a resolution of 62km, 0.5625 degrees. (Depending on the parameter, the data are archived either as spectral coefficients with a triangular truncation of T639 (HRES) and T319 (EDA) or on a reduced Gaussian grid with a resolution of N320 (HRES) and N160 (EDA). These grids are so called "linear grids", sometimes referred to as TL639 (HRES) and TL319 (EDA).)

The wave data are produced and archived on a different grid to that of the atmospheric model, namely a reduced latitude/longitude grid with a resolution of 0.36 degrees (HRES) and 1.0 degrees (EDA).

ERA5 data available from the CDS disks has been pre-interpolated to a regular latitude/longitude grid appropriate for that data.

The article Model grid box and time step might be useful.

Temporal frequency

For sub-daily data for the HRES (stream=oper/wave) the analyses (type=an) are available hourly. The short forecasts, run from 06 and 18 UTC, have hourly steps from 0 to 18 hours. For the EDA, the sub-daily non-wave data (stream=enda) are available every 3 hours but the sub-daily wave data (stream=ewda) are available hourly.

Wave spectra

The ERA5 wave model uses wave spectra with 24 directions and 30 frequencies (see "2D wave spectra (single)", Table 7), for more information see the article About ERA wave spectra.

Mean rates and accumulations

The accumulations in the short forecasts (from 06 and 18 UTC) of ERA5 are treated differently compared with those in ERA-Interim (where they are from the beginning of the forecast to the forecast step). In the short forecasts of ERA5 the accumulations are since the previous post processing (archiving), so for:

  • HRES: accumulations are over the hour ending at the forecast step
  • EDA: accumulations are over the 3 hours ending at the forecast step
  • Monthly means of daily means (stream=moda/edmo): accumulations have been scaled to have units that include "per day", see section Monthly means

Mean rate parameters in ERA5 are similar to accumulations except that the accumulations have been divided by the length of the processing period in seconds to produce temporally averaged rates, so the units include "per second". For "surface or single level" parameters, the mean rates (Table 4) provide similar information to the accumulations (Table 3), but with the different units.

Note that:

  • For the CDS time, or validity time, of 00 UTC, the mean rates and accumulations are over the hour (3 hours for the EDA) ending at 00 UTC i.e. the mean or accumulation is during the previous day.
  • Mean rates and accumulations are not available from the analyses.
  • Mean rates and accumulations at step=0 have values of zero because the length of the processing period is zero.

Minimum/maximum since the previous post processing

The short forecasts of ERA5 contain some surface and single level parameters that are the minimum or maximum value since the previous post processing (archiving), see Table 5 below. So, for:

  • HRES: the minimum or maximum values are in the hour ending at the forecast step
  • EDA: the minimum or maximum values are in the 3 hours ending at the forecast step

Monthly means

In addition to the sub-daily data, most parameters are also available as monthly means. For the surface and single level parameters, there are some exceptions which are listed in Table 8.

Monthly means are available in two forms:

  • Synoptic monthly means, for each particular time and forecast step (stream=mnth/wamo/edmm/ewmm) - in the CDS, referred to as "monthly averaged by hour of day".
  • Monthly means of daily means, for the month as a whole (stream=moda/wamd/edmo/ewmo) - in the CDS, referred to as "monthly averaged". These monthly means are created from the hourly data for the reanalysis (HRES) and 3 hourly data for the ensemble members (EDA).

Monthly means for:

  • forecast parameters are created using the first 12 hours of the twice daily short forecasts (beginning at 06 and 18 UTC).
  • analysis and instantaneous forecast parameters are created from data with a valid time in the month, between 00 and 23 UTC, which excludes the time 00 UTC on the first day of the following month.
  • accumulation and mean rate forecast parameters are created from data with a forecast period falling within the month. Therefore, monthly means of daily means for accumulations and mean rates are created from contiguous data with forecast periods spanning from 00 UTC on the first day of the month to 00 UTC on the first day of the following month.

The accumulations in monthly means of daily means (stream=moda/edmo) have been scaled to have units that include "per day", so for accumulations in these streams:

  • The hydrological parameters are in units of "m of water per day" and so they should be multiplied by 1000 to convert to kgm-2day-1 or mmday-1.
  • The energy (turbulent and radiative) and momentum fluxes should be divided by 86400 seconds (24 hours) to convert to the commonly used units of Wm-2 and Nm-2, respectively.

Ensemble means and standard deviations

For the EDA sub-daily data (stream=enda/ewda), compared with HRES sub-daily data (stream=oper/wave), there are also ensemble means and standard deviations (type=em/es).

Ensemble standard deviation is often referred to as ensemble spread and is calculated as the standard deviation of the 10-members in the ensemble (i.e., including the control). It is not the sample stdv, so we divide by 10 rather than 9 (N-1). 

Ensemble means and standard deviations contain analysed parameters when step=0, otherwise they contain forecast parameters. However, only surface and pressure level data (levtype=sfc/pl) contain forecast steps beyond 3 hours. There are no monthly means for ensemble means and standard deviations.

Data format

Model level fields are in GRIB2 format. All other fields are in GRIB1, unless otherwise indicated.

Level listings

Pressure levels: 1000/975/950/925/900/875/850/825/800/775/750/700/650/600/550/500/450/400/350/300/250/225/200/175/150/125/100/70/50/30/20/10/7/5/3/2/1

Potential temperature levels: 265/275/285/300/315/320/330/350/370/395/430/475/530/600/700/850

Potential vorticity level: 2000

Model levels: 1/to/137, which are described at https://www.ecmwf.int/en/forecasts/documentation-and-support/137-model-levels.

Parameter listings

Tables 1-6 below describe the surface and single level parameters (levtype=sfc), Table 7 describes wave parameters, Table 8 describes the monthly mean exceptions for surface and single level and wave parameters and Tables 9-13 describe upper air parameters on various levtypes. Information on all ECMWF parameters is available from the ECMWF parameter database.

Parameters described as "instantaneous"  below, are valid at the specified time.


Table 1: stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc: surface and single level parameters: invariants

count

name

units

shortName

paramId

an

fc

1

Lake cover

(0 - 1)

cl

26

x

x

2

Lake depth

m

dl

228007

x

x

3

Low vegetation cover

(0 - 1)

cvl

27

x


4

High vegetation cover

(0 - 1)

cvh

28

x


5

Type of low vegetation

~

tvl

29

x


6

Type of high vegetation

~

tvh

30

x


7

Soil type

~

slt

43

x


8

Standard deviation of filtered subgrid orography

m

sdfor

74

x


9

Geopotential

m**2 s**-2

z

129

x

x

10

Standard deviation of orography

~

sdor

160

x


11

Anisotropy of sub-gridscale orography

~

isor

161

x


12

Angle of sub-gridscale orography

radians

anor

162

x


13

Slope of sub-gridscale orography

~

slor

163

x


14

Land-sea mask

(0 - 1)

lsm

172

x

x



Table 2: stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc: surface and single level parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Convective inhibition

J kg**-1

cin

228001


x

2

Friction velocity

m s**-1

zust

228003


x

3

Lake mix-layer temperature

K

lmlt

228008

x

x

4

Lake mix-layer depth

m

lmld

228009

x

x

5

Lake bottom temperature

K

lblt

228010

x

x

6

Lake total layer temperature

K

ltlt

228011

x

x

7

Lake shape factor

dimensionless

lshf

228012

x

x

8

Lake ice temperature

K

lict

228013

x

x

9

Lake ice depth

m

licd

228014

x

x

10

UV visible albedo for direct radiation

(0 - 1)

aluvp

15

x

x

11

Minimum vertical gradient of refractivity inside trapping layer

m**-1

dndzn

228015


x

12

UV visible albedo for diffuse radiation

(0 - 1)

aluvd

16

x

x

13

Mean vertical gradient of refractivity inside trapping layer

m**-1

dndza

228016


x

14

Near IR albedo for direct radiation

(0 - 1)

alnip

17

x

x

15

Duct base height

m

dctb

228017


x

16

Near IR albedo for diffuse radiation

(0 - 1)

alnid

18

x

x

17

Trapping layer base height

m

tplb

228018


x

18

Trapping layer top height

m

tplt

228019


x

19

Cloud base height

m

cbh

228023


x

20

Zero degree level

m

deg0l

228024


x

21

Instantaneous 10 metre wind gust

m s**-1

i10fg

228029


x

22

Sea ice area fraction

(0 - 1)

ci

31

x

x

23

Snow albedo

(0 - 1)

asn

32

x

x

24

Snow density

kg m**-3

rsn

33

x

x

25

Sea surface temperature

K

sst

34

x

x

26

Ice temperature layer 1

K

istl1

35

x

x

27

Ice temperature layer 2

K

istl2

36

x

x

28

Ice temperature layer 3

K

istl3

37

x

x

29

Ice temperature layer 4

K

istl4

38

x

x

30

Volumetric soil water layer 1

m**3 m**-3

swvl1

39

x

x

31

Volumetric soil water layer 2

m**3 m**-3

swvl2

40

x

x

32

Volumetric soil water layer 3

m**3 m**-3

swvl3

41

x

x

33

Volumetric soil water layer 4

m**3 m**-3

swvl4

42

x

x

34

Convective available potential energy

J kg**-1

cape

59

x

x

35

Leaf area index, low vegetation

m**2 m**-2

lai_lv

66

x

x

36

Leaf area index, high vegetation

m**2 m**-2

lai_hv

67

x

x

37

Neutral wind at 10 m u-component

m s**-1

u10n

228131

x

x

38

Neutral wind at 10 m v-component

m s**-1

v10n

228132

x

x

39

Surface pressure

Pa

sp

134

x

x

40

Soil temperature level 1

K

stl1

139

x

x

41

Snow depth

m of water equivalent

sd

141

x

x

42

Charnock

~

chnk

148

x

x

43

Mean sea level pressure

Pa

msl

151

x

x

44

Boundary layer height

m

blh

159

x

x

45

Total cloud cover

(0 - 1)

tcc

164

x

x

46

10 metre U wind component

m s**-1

10u

165

x

x

47

10 metre V wind component

m s**-1

10v

166

x

x

48

2 metre temperature

K

2t

167

x

x

49

2 metre dewpoint temperature

K

2d

168

x

x

50

Soil temperature level 2

K

stl2

170

x

x

51

Soil temperature level 3

K

stl3

183

x

x

52

Low cloud cover

(0 - 1)

lcc

186

x

x

53

Medium cloud cover

(0 - 1)

mcc

187

x

x

54

High cloud cover

(0 - 1)

hcc

188

x

x

55

Skin reservoir content

m of water equivalent

src

198

x

x

56

Instantaneous large-scale surface precipitation fraction

(0 - 1)

ilspf

228217


x

57

Convective rain rate

kg m**-2 s**-1

crr

228218


x

58

Large scale rain rate

kg m**-2 s**-1

lsrr

228219


x

59

Convective snowfall rate water equivalent

kg m**-2 s**-1

csfr

228220


x

60

Large scale snowfall rate water equivalent

kg m**-2 s**-1

lssfr

228221


x

61

Instantaneous eastward turbulent surface stress

N m**-2

iews

229

x

x

62

Instantaneous northward turbulent surface stress

N m**-2

inss

230

x

x

63

Instantaneous surface sensible heat flux

W m**-2

ishf

231

x

x

64

Instantaneous moisture flux

kg m**-2 s**-1

ie

232

x

x

65

Skin temperature

K

skt

235

x

x

66

Soil temperature level 4

K

stl4

236

x

x

67

Temperature of snow layer

K

tsn

238

x

x

68

Forecast albedo

(0 - 1)

fal

243

x

x

69

Forecast surface roughness

m

fsr

244

x

x

70

Forecast logarithm of surface roughness for heat

~

flsr

245

x

x

71

100 metre U wind component

m s**-1

100u

228246

x

x

72

100 metre V wind component

m s**-1

100v

228247

x

x

73

Precipitation type

code table (4.201)

ptype

260015*


x

74

K index

K

kx

260121*


x

75

Total totals index

K

totalx

260123*


x

*GRIB2 format



Table 3: stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc: surface and single level parameters: accumulations

count

name

units

shortName

paramId

an

fc

1

Large-scale precipitation fraction

s

lspf

50


x

2

Downward UV radiation at the surface

J m**-2

uvb

57


x

3

Boundary layer dissipation

J m**-2

bld

145


x

4

Surface sensible heat flux

J m**-2

sshf

146


x

5

Surface latent heat flux

J m**-2

slhf

147


x

6

Surface solar radiation downwards

J m**-2

ssrd

169


x

7

Surface thermal radiation downwards

J m**-2

strd

175


x

8

Surface net solar radiation

J m**-2

ssr

176


x

9

Surface net thermal radiation

J m**-2

str

177


x

10

Top net solar radiation

J m**-2

tsr

178


x

11

Top net thermal radiation

J m**-2

ttr

179


x

12

Eastward turbulent surface stress

N m**-2 s

ewss

180


x

13

Northward turbulent surface stress

N m**-2 s

nsss

181


x

14

Eastward gravity wave surface stress

N m**-2 s

lgws

195


x

15

Northward gravity wave surface stress

N m**-2 s

mgws

196


x

16

Gravity wave dissipation

J m**-2

gwd

197


x

17

Top net solar radiation, clear sky

J m**-2

tsrc

208


x

18

Top net thermal radiation, clear sky

J m**-2

ttrc

209


x

19

Surface net solar radiation, clear sky

J m**-2

ssrc

210


x

20

Surface net thermal radiation, clear sky

J m**-2

strc

211


x

21

TOA incident solar radiation

J m**-2

tisr

212


x

22

Vertically integrated moisture divergence

kg m**-2

vimd

213


x

23

Total sky direct solar radiation at surface

J m**-2

fdir

228021


x

24

Clear-sky direct solar radiation at surface

J m**-2

cdir

228022


x

25

Surface solar radiation downward clear-sky

J m**-2

ssrdc

228129


x

26

Surface thermal radiation downward clear-sky

J m**-2

strdc

228130


x

27

Surface runoff

m

sro

8


x

28

Sub-surface runoff

m

ssro

9


x

29

Snow evaporation

m of water equivalent

es

44


x

30

Snowmelt

m of water equivalent

smlt

45


x

31

Large-scale precipitation

m

lsp

142


x

32

Convective precipitation

m

cp

143


x

33

Snowfall

m of water equivalent

sf

144


x

34

Evaporation

m of water equivalent

e

182


x

35

Runoff

m

ro

205


x

36

Total precipitation

m

tp

228


x

37

Convective snowfall

m of water equivalent

csf

239


x

38

Large-scale snowfall

m of water equivalent

lsf

240


x

39

Potential evaporation

m

pev

228251


x

Accumulations are described in section Mean rates and accumulations. The accumulations in monthly means of daily means (stream=moda/edmo) have been scaled to have units that include "per day", so for accumulations in these streams:

  • The hydrological parameters are in units of "m of water per day" and so they should be multiplied by 1000 to convert to kg m-2 day-1 or mm day-1.
  • Energy (turbulent and radiative) and momentum fluxes should be divided by 86400 seconds (24 hours) to convert to the commonly used units of W m-2 and N m-2, respectively.


 Table 4: stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc: surface and single level parameters: mean rates

countnameunitsshortNameparamIdanfc
1

Mean surface runoff rate

kg m**-2 s**-1

msror

235020


x
2

Mean sub-surface runoff rate

kg m**-2 s**-1

mssror

235021


x
3

Mean snow evaporation rate

kg m**-2 s**-1

mser

235023


x
4

Mean snowmelt rate

kg m**-2 s**-1

msmr

235024


x
5

Mean large-scale precipitation fraction

Proportion

mlspf

235026


x
6

Mean surface downward UV radiation flux

W m**-2

msdwuvrf

235027


x
7

Mean large-scale precipitation rate

kg m**-2 s**-1

mlspr

235029


x
8

Mean convective precipitation rate

kg m**-2 s**-1

mcpr

235030


x
9

Mean snowfall rate

kg m**-2 s**-1

msr

235031


x
10

Mean boundary layer dissipation

W m**-2

mbld

235032


x
11

Mean surface sensible heat flux

W m**-2

msshf

235033


x
12

Mean surface latent heat flux

W m**-2

mslhf

235034


x
13

Mean surface downward short-wave radiation flux

W m**-2

msdwswrf

235035


x
14

Mean surface downward long-wave radiation flux

W m**-2

msdwlwrf

235036


x
15

Mean surface net short-wave radiation flux

W m**-2

msnswrf

235037


x
16

Mean surface net long-wave radiation flux

W m**-2

msnlwrf

235038


x
17

Mean top net short-wave radiation flux

W m**-2

mtnswrf

235039


x
18

Mean top net long-wave radiation flux

W m**-2

mtnlwrf

235040


x
19

Mean eastward turbulent surface stress

N m**-2

metss

235041


x
20

Mean northward turbulent surface stress

N m**-2

mntss

235042


x
21

Mean evaporation rate

kg m**-2 s**-1

mer

235043


x
22

Mean eastward gravity wave surface stress

N m**-2

megwss

235045


x
23

Mean northward gravity wave surface stress

N m**-2

mngwss

235046


x
24

Mean gravity wave dissipation

W m**-2

mgwd

235047


x
25

Mean runoff rate

kg m**-2 s**-1

mror

235048


x
26

Mean top net short-wave radiation flux, clear sky

W m**-2

mtnswrfcs

235049


x
27

Mean top net long-wave radiation flux, clear sky

W m**-2

mtnlwrfcs

235050


x
28

Mean surface net short-wave radiation flux, clear sky

W m**-2

msnswrfcs

235051


x
29

Mean surface net long-wave radiation flux, clear sky

W m**-2

msnlwrfcs

235052


x
30

Mean top downward short-wave radiation flux

W m**-2

mtdwswrf

235053


x
31

Mean vertically integrated moisture divergence

kg m**-2 s**-1

mvimd

235054


x
32

Mean total precipitation rate

kg m**-2 s**-1

mtpr

235055


x
33

Mean convective snowfall rate

kg m**-2 s**-1

mcsr

235056


x
34

Mean large-scale snowfall rate

kg m**-2 s**-1

mlssr

235057


x
35

Mean surface direct short-wave radiation flux

W m**-2

msdrswrf

235058


x
36

Mean surface direct short-wave radiation flux, clear sky

W m**-2

msdrswrfcs

235059


x
37

Mean surface downward short-wave radiation flux, clear sky

W m**-2

msdwswrfcs

235068


x
38

Mean surface downward long-wave radiation flux, clear sky

W m**-2

msdwlwrfcs

235069


x
39

Mean potential evaporation rate

kg m**-2 s**-1

mper

235070


x

The mean rates in Table 4 provide similar information to the accumulations in Table 3, except that they are expressed as temporal averages instead of accumulations, and so have units of "per second". The hydrological parameters are in units of "kg m-2 s-1" and so they can be multiplied by 86400 seconds (24 hours) to convert to kg m-2 day-1 or mm day-1.


Table 5: stream=oper/enda, levtype=sfc: surface and single level parameters: minimum/maximum

count

name

units

shortName

paramId

an

fc

1

10 metre wind gust since previous post-processing

m s**-1

10fg

49


x

2

Maximum temperature at 2 metres since previous post-processing

K

mx2t

201


x

3

Minimum temperature at 2 metres since previous post-processing

K

mn2t

202


x

4

Maximum total precipitation rate since previous post-processing

kg m**-2 s**-1

mxtpr

228226


x

5

Minimum total precipitation rate since previous post-processing

kg m**-2 s**-1

mntpr

228227


x



Table 6: stream=oper/enda/mnth/moda/edmm/edmo, levtype=sfc: surface and single level parameters: vertical integrals (not available for type=em/es) and total column: instantaneous

count

name

units

shortName

paramId

an

fc

1

Vertical integral of mass of atmosphere

kg m**-2

vima

162053

x

x

2

Vertical integral of temperature

K kg m**-2

vit

162054

x

x

3

Vertical integral of kinetic energy

J m**-2

vike

162059

x

x

4

Vertical integral of thermal energy

J m**-2

vithe

162060

x

x

5

Vertical integral of potential+internal energy

J m**-2

vipie

162061

x

x

6

Vertical integral of potential+internal+latent energy

J m**-2

vipile

162062

x

x

7

Vertical integral of total energy

J m**-2

vitoe

162063

x

x

8

Vertical integral of energy conversion

W m**-2

viec

162064

x

x

9

Vertical integral of eastward mass flux

kg m**-1 s**-1

vimae

162065

x

x

10

Vertical integral of northward mass flux

kg m**-1 s**-1

viman

162066

x

x

11

Vertical integral of eastward kinetic energy flux

W m**-1

vikee

162067

x

x

12

Vertical integral of northward kinetic energy flux

W m**-1

viken

162068

x

x

13

Vertical integral of eastward heat flux

W m**-1

vithee

162069

x

x

14

Vertical integral of northward heat flux

W m**-1

vithen

162070

x

x

15

Vertical integral of eastward water vapour flux

kg m**-1 s**-1

viwve

162071

x

x

16

Vertical integral of northward water vapour flux

kg m**-1 s**-1

viwvn

162072

x

x

17

Vertical integral of eastward geopotential flux

W m**-1

vige

162073

x

x

18

Vertical integral of northward geopotential flux

W m**-1

vign

162074

x

x

19

Vertical integral of eastward total energy flux

W m**-1

vitoee

162075

x

x

20

Vertical integral of northward total energy flux

W m**-1

vitoen

162076

x

x

21

Vertical integral of eastward ozone flux

kg m**-1 s**-1

vioze

162077

x

x

22

Vertical integral of northward ozone flux

kg m**-1 s**-1

viozn

162078

x

x

23

Vertical integral of divergence of cloud liquid water flux

kg m**-2 s**-1

vilwd

162079

x

x

24

Vertical integral of divergence of cloud frozen water flux

kg m**-2 s**-1

viiwd

162080

x

x

25

Vertical integral of divergence of mass flux

kg m**-2 s**-1

vimad

162081

x

x

26

Vertical integral of divergence of kinetic energy flux

W m**-2

viked

162082

x

x

27

Vertical integral of divergence of thermal energy flux

W m**-2

vithed

162083

x

x

28

Vertical integral of divergence of moisture flux

kg m**-2 s**-1

viwvd

162084

x

x

29

Vertical integral of divergence of geopotential flux

W m**-2

vigd

162085

x

x

30

Vertical integral of divergence of total energy flux

W m**-2

vitoed

162086

x

x

31

Vertical integral of divergence of ozone flux

kg m**-2 s**-1

viozd

162087

x

x

32

Vertical integral of eastward cloud liquid water flux

kg m**-1 s**-1

vilwe

162088

x

x

33

Vertical integral of northward cloud liquid water flux

kg m**-1 s**-1

vilwn

162089

x

x

34

Vertical integral of eastward cloud frozen water flux

kg m**-1 s**-1

viiwe

162090

x

x

35

Vertical integral of northward cloud frozen water flux

kg m**-1 s**-1

viiwn

162091

x

x

36

Vertical integral of mass tendency

kg m**-2 s**-1

vimat

162092

x


37

Total column cloud liquid water

kg m**-2

tclw

78

x

x

38

Total column cloud ice water

kg m**-2

tciw

79

x

x

39

Total column supercooled liquid water

kg m**-2

tcslw

228088


x

40

Total column rain water

kg m**-2

tcrw

228089

x

x

41

Total column snow water

kg m**-2

tcsw

228090

x

x

42

Total column water

kg m**-2

tcw

136

x

x

43

Total column water vapour

kg m**-2

tcwv

137

x

x

44

Total column ozone

kg m**-2

tco3

206

x

x



Table 7: stream=wave/ewda/wamo/wamd/ewmm/ewmo: wave parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Significant wave height of first swell partition

m

swh1

140121

x

x

2

Mean wave direction of first swell partition

degrees

mwd1

140122

x

x

3

Mean wave period of first swell partition

s

mwp1

140123

x

x

4

Significant wave height of second swell partition

m

swh2

140124

x

x

5

Mean wave direction of second swell partition

degrees

mwd2

140125

x

x

6

Mean wave period of second swell partition

s

mwp2

140126

x

x

7

Significant wave height of third swell partition

m

swh3

140127

x

x

8

Mean wave direction of third swell partition

degrees

mwd3

140128

x

x

9

Mean wave period of third swell partition

s

mwp3

140129

x

x

10

Wave Spectral Skewness

dimensionless

wss

140207

x

x

11

Free convective velocity over the oceans

m s**-1

wstar

140208

x

x

12

Air density over the oceans

kg m**-3

rhoao

140209

x

x

13

Normalized energy flux into waves

dimensionless

phiaw

140211

x

x

14

Normalized energy flux into ocean

dimensionless

phioc

140212

x

x

15

Normalized stress into ocean

dimensionless

tauoc

140214

x

x

16

U-component stokes drift

m s**-1

ust

140215

x

x

17

V-component stokes drift

m s**-1

vst

140216

x

x

18

Period corresponding to maximum individual wave height

s

tmax

140217

x

x

19

Maximum individual wave height

m

hmax

140218

x

x

20

Model bathymetry

m

wmb

140219

x

x

21

Mean wave period based on first moment

s

mp1

140220

x

x

22

Mean wave period based on second moment

s

mp2

140221

x

x

23

Wave spectral directional width

dimensionless

wdw

140222

x

x

24

Mean wave period based on first moment for wind waves

s

p1ww

140223

x

x

25

Mean wave period based on second moment for wind waves

s

p2ww

140224

x

x

26

Wave spectral directional width for wind waves

dimensionless

dwww

140225

x

x

27

Mean wave period based on first moment for swell

s

p1ps

140226

x

x

28

Mean wave period based on second moment for swell

s

p2ps

140227

x

x

29

Wave spectral directional width for swell

dimensionless

dwps

140228

x

x

30

Significant height of combined wind waves and swell

m

swh

140229

x

x

31

Mean wave direction

degrees

mwd

140230

x

x

32

Peak wave period

s

pp1d

140231

x

x

33

Mean wave period

s

mwp

140232

x

x

34

Coefficient of drag with waves

dimensionless

cdww

140233

x

x

35

Significant height of wind waves

m

shww

140234

x

x

36

Mean direction of wind waves

degrees

mdww

140235

x

x

37

Mean period of wind waves

s

mpww

140236

x

x

38

Significant height of total swell

m

shts

140237

x

x

39

Mean direction of total swell

degrees

mdts

140238

x

x

40

Mean period of total swell

s

mpts

140239

x

x

41

Mean square slope of waves

dimensionless

msqs

140244

x

x

42

10 metre wind speed

m s**-1

wind

140245

x

x

43

Altimeter wave height

m

awh

140246

x


44

Altimeter corrected wave height

m

acwh

140247

x


45

Altimeter range relative correction

~

arrc

140248

x


46

10 metre wind direction

degrees

dwi

140249

x

x

47

Wave spectral kurtosis

dimensionless

wsk

140252

x

x

48

Benjamin-Feir index

dimensionless

bfi

140253

x

x

49

Wave spectral peakedness

dimensionless

wsp

140254

x

x

50

2D wave spectra (single)

m**2 s radian**-1

2dfd

140251*

x


*for 30 frequencies and 24 directions


Table 8: stream=mnth/moda/edmm/edmo, levtype=sfc or wamo/wamd/ewmm/ewmo: monthly mean surface and single level and wave parameters: exceptions from Tables 1-7

count

name

units

shortName

paramId

an

fc

1

UV visible albedo for direct radiation

(0 - 1)

aluvp

15

x

no mean

2

UV visible albedo for diffuse radiation

(0 - 1)

aluvd

16

x

no mean

3

Near IR albedo for direct radiation

(0 - 1)

alnip

17

x

no mean

4

Near IR albedo for diffuse radiation

(0 - 1)

alnid

18

x

no mean

5

Magnitude of turbulent surface stress

N m**-2 s

magss

48


x

6Mean magnitude of turbulent surface stressN m**-2mmtss235025
x

7

10 metre wind gust since previous post-processing

m s**-1

10fg

49


no mean

8

Maximum temperature at 2 metres since previous post-processing

K

mx2t

201


no mean

9

Minimum temperature at 2 metres since previous post-processing

K

mn2t

202


no mean

10

10 metre wind speed

m s**-1

10si

207

x

x

11

Maximum total precipitation rate since previous post-processing

kg m**-2 s**-1

mxtpr

228226


no mean

12

Minimum total precipitation rate since previous post-processing

kg m**-2 s**-1

mntpr

228227


no mean

13

Altimeter wave height

m

awh

140246

no mean


14

Altimeter corrected wave height

m

acwh

140247

no mean


15

Altimeter range relative correction

~

arrc

140248

no mean


16

2D wave spectra (single)

m**2 s radian**-1

2dfd

140251

no mean



Table 9: stream=oper/enda/mnth/moda/edmm/edmo, levtype=pl: pressure level parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Potential vorticity

K m**2 kg**-1 s**-1

pv

60

x

x

2

Specific rain water content

kg kg**-1

crwc

75

x

x

3

Specific snow water content

kg kg**-1

cswc

76

x

x

4

Geopotential

m**2 s**-2

z

129

x

x

5

Temperature

K

t

130

x

x

6

U component of wind

m s**-1

u

131

x

x

7

V component of wind

m s**-1

v

132

x

x

8

Specific humidity

kg kg**-1

q

133

x

x

9

Vertical velocity

Pa s**-1

w

135

x

x

10

Vorticity (relative)

s**-1

vo

138

x

x

11

Divergence

s**-1

d

155

x

x

12

Relative humidity

%

r

157

x

x

13

Ozone mass mixing ratio

kg kg**-1

o3

203

x

x

14

Specific cloud liquid water content

kg kg**-1

clwc

246

x

x

15

Specific cloud ice water content

kg kg**-1

ciwc

247

x

x

16

Fraction of cloud cover

(0 - 1)

cc

248

x

x



Table 10: stream=oper/enda/mnth/moda/edmm/edmo, levtype=pt: potential temperature level parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Montgomery potential

m**2 s**-2

mont

53

x


2

Pressure

Pa

pres

54

x


3

Potential vorticity

K m**2 kg**-1 s**-1

pv

60

x


4

U component of wind

m s**-1

u

131

x


5

V component of wind

m s**-1

v

132

x


6

Specific humidity

kg kg**-1

q

133

x


7

Vorticity (relative)

s**-1

vo

138

x


8

Divergence

s**-1

d

155

x


9

Ozone mass mixing ratio

kg kg**-1

o3

203

x




Table 11: stream=oper/enda/mnth/moda/edmm/edmo, levtype=pv: potential vorticity level parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Potential temperature

K

pt

3

x


2

Pressure

Pa

pres

54

x


3

Geopotential

m**2 s**-2

z

129

x


4

U component of wind

m s**-1

u

131

x


5

V component of wind

m s**-1

v

132

x


6

Specific humidity

kg kg**-1

q

133

x


7

Ozone mass mixing ratio

kg kg**-1

o3

203

x




Table 12: stream=oper/enda/mnth/moda/edmm/edmo, levtype=ml: model level parameters: instantaneous

count

name

units

shortName

paramId

an

fc

1

Specific rain water content

kg kg**-1

crwc

75

x

x

2

Specific snow water content

kg kg**-1

cswc

76

x

x

3

Eta-coordinate vertical velocity

s**-1

etadot

77

x

x

4

Geopotential*

m**2 s**-2

z

129

x

x

5

Temperature

K

t

130

x

x

6

U component of wind

m s**-1

u

131

x

x

7

V component of wind

m s**-1

v

132

x

x

8

Specific humidity

kg kg**-1

q

133

x

x

9

Vertical velocity

Pa s**-1

w

135

x

x

10

Vorticity (relative)

s**-1

vo

138

x

x

11

Logarithm of surface pressure*

~

lnsp

152

x

x

12

Divergence

s**-1

d

155

x

x

13

Ozone mass mixing ratio

kg kg**-1

o3

203

x

x

14

Specific cloud liquid water content

kg kg**-1

clwc

246

x

x

15

Specific cloud ice water content

kg kg**-1

ciwc

247

x

x

16

Fraction of cloud cover

(0 - 1)

cc

248

x

x

*Only archived on level=1.


Table 13: stream=oper/enda/mnth/moda/edmm/edmo, levtype=ml: model level parameters: mean rates

countnameunitsshortNameparamIdanfc
1Mean temperature tendency due to short-wave radiationK s**-1mttswr235001
x
2Mean temperature tendency due to long-wave radiationK s**-1mttlwr235002
x
3Mean temperature tendency due to short-wave radiation, clear skyK s**-1mttswrcs235003
x
4Mean temperature tendency due to long-wave radiation, clear skyK s**-1mttlwrcs235004
x
5Mean temperature tendency due to parametrisationsK s**-1mttpm235005
x
6Mean specific humidity tendency due to parametrisationskg kg**-1 s**-1mqtpm235006
x
7Mean eastward wind tendency due to parametrisationsm s**-2mutpm235007
x
8Mean northward wind tendency due to parametrisationsm s**-2mvtpm235008
x
9Mean updraught mass flux*kg m**-2 s**-1mumf235009
x
10Mean downdraught mass flux*kg m**-2 s**-1mdmf235010
x
11Mean updraught detrainment ratekg m**-3 s**-1mudr235011
x
12Mean downdraught detrainment ratekg m**-3 s**-1mddr235012
x
13Mean total precipitation flux*kg m**-2 s**-1mtpf235013
x
14Mean turbulent diffusion coefficient for heat*m**2 s**-1mtdch235014
x

*These parameters provide data for the model half levels, at the interfaces of the model layers.

Observations

The observations (satellite and in-situ) used as input into ERA5 are listed below.

Satellite Data

SensorSatelliteSatellite agencyData provider+

Measurement

(sensitivities exploited in ERA5 / variables analysed)

Satellite radiances (infrared and microwave)



AIRSAQUANASANOAABT (T, humidity and ozone)
AMSR-2GCOM-W1*JAXA

BT  (column water vapour, cloud liquid water,

precipitation and ocean surface wind speed)

AMSREAQUA*JAXA

BT  (column water vapour, cloud liquid water,

precipitation and ocean surface wind speed)

AMSUANOAA-15/16/17/18/19, AQUA, METOP-A/BNOAA,ESA,EUMETSAT
BT (T)
AMSUBNOAA-15/16/17NOAA
BT (humidity)
ATMSNPPNOAA
BT (T and humidity)
CRISNPPNOAA
BT (T, humidity and ozone)
HIRSTIROS-N, NOAA-6 /7/8/9/11/14NOAA
BT (T, humidity and ozone)
IASIMETOP-A/BEUMETSAT/ESAEUMETSATBT (T, humidity and ozone)
GMIGPMNASA/JAXA

BT (humidity, column water vapour,

cloud liquid water, precipitation,

ocean surface wind speed)

MHSNOAA-18/19, METOP-A/BNOAA, EUMETSAT/ESA
BT (humidity and precipitation)
MSUTIROS-N, NOAA-6 to 12, NOAA-14

BT (T)
MWHSFY-3-A/BNRSCC
BT (humidity)
MWHS2FY-3-CCMA
BT (T, humidity and precipitation)
MWTSFY-3A/BNRSCC
BT (T)
MWTS2FY-3CCMA
BT (T)
SSM/IDMSP-11*/13*/14*/15*US NavyNOAA,CMSAF*

BT (column water vapour, cloud liquid water,

precipitation and ocean surface wind speed)

SSMISDMSP-16/17/18US NavyNOAA

BT (T,  humidity,  column water vapour,

cloud liquid water, precipitation and ocean surface wind speed)

SSUTIROS-N, NOAA-6/7/8/9/11/14NOAA
BT (T)
TMITRMMNASA/JAXA
BT (column water vapour, cloud liquid water,

precipitation, ocean surface wind speed)

MVIRIMETEOSAT 5/7EUMETSAT/ESAEUMETSATBT (water vapour, surface/cloud top T)
SEVIRIMETEOSAT-8*/9*/10EUMETSAT/ESAEUMETSATBT (water vapour, surface/cloud top T)
GOES IMAGERGOES-8/9/10/11/12/13/15NOAACIMMS,NESDISBT (water vapour, surface/cloud top T)
MTSAT IMAGERMTSAT-1R/MTSAT-2JMA
BT (water vapour, surface/cloud top T)
AHIHimawari-8JMA
BT (water vapour, surface/cloud top T)
Satellite retrievals from radiance data



MVIRIMETEOSAT-2*/3*/4*/5*/7*EUMETSAT/ESAEUMETSATwind vector
SEVIRIMETEOSAT-8*/9*/10EUMETSAT/ESAEUMETSATwind vector
GOES IMAGERGOES-4-6/8*/9*/10*/11*/12*/13*/15*NOAACIMMS*,NESDISwind vector
GMS IMAGERGMS-1*/2/3*/4*/5*JMA
wind vector
MTSAT IMAGERMTSAT-1R*/MTSAT2JMA
wind vector
AHIHimawari-8JMAJMAwind vector
AVHRRNOAA-7 /9/10/11/12/14 to 18, METOP-ANOAACIMMS,EUMETSATwind vector
MODISAQUA/TERRANASANESDIS,CIMMSwind vector
GOMEERS-2*ESA
Ozone
GOME-2METOP*-A/BESA/EUMETSAT
Ozone
MIPASENVISAT*ESA
Ozone
MLSEOS-AURA*NASA
Ozone
OMIEOS-AURA*NASA
Ozone
SBUV,SBUV-2NIMBUS-7*,NOAA*9/11/14/16/17/18/19NOAANASAOzone
SCIAMACHYENVISAT*ESA
Ozone
TOMSNIMBUS-7*,METEOR-3-5,ADEOS-1*,EARTH PROBENASA
Ozone
Satellite GPS-Radio Occultation data



BlackJackCHAMP,GRACE*-A/B,SAC-C*DLR,NASA/DLR,NASA/COMAEGFZ,UCAR*Bending angle
GRASMETOP-A/BEUMETSAT/ESAEUMETSATBending angle
IGORTerraSAR-X*, TanDEM-X, COSMIC*-1 to 6NSPO/NOAAGFZ,UCAR*Bending angle
Satellite scatterometer data



AMIERS-1,ERS-2ESA
Backscatter sigma0, soil moisture
ASCATMETOP-A/B*EUMETSAT/ESAEUMETSAT/TU WienBackscatter sigma0, soil moisture
OSCATOCEANSAT-2ISROKNMIBackscatter sigma0
SEAWINDSQUIKSCATNASANASABackscatter sigma0
Satellite Altimeter data



RAERS-1*/2*ESA
Wave Height
RA-2ENVISAT*ESA
Wave Height
Poseidon-2JASON-1*CNES/NASACNESWave Height
Poseidon-3JASON-2CNES/NOAA/NASA/EUMETSATNOAA/EUMETSATWave Height
SIRALCRYOSAT-2ESA
Wave Height
AltiKaSARALCNES/ISROEUMETSATWave Height

* reprocessed dataset
+ when different than the satellite agency

In-situ data, provided by WMO WIS

Dataset nameObservation typeMeasurement
SYNOPLand stationSurface Pressure, Temperature, wind, humidity
METARLand stationSurface Pressure, Temperature, wind,humidity
DRIBU/DRIBU-BATHY/DRIBU-TESAC/BUFR Drifting BuoyDrifting buoys10m-wind, Surface Pressure
BUFR Moored BuoyMoored buoys10m-wind, Surface Pressure
SHIPship stationSurface Pressure, Temperature, wind, humidity
Land/ship PILOTRadiosondeswind profiles
American Wind ProfilerRadarwind profiles
European Wind ProfilerRadarwind profiles
Japanese Wind ProfilerRadarwind profiles
TEMP SHIPRadiosondesTemperature, wind, humidity profiles
DROP SondeAircraft-sondesTemperature, wind profiles
Land/Mobile TEMPRadiosondesTemperature, wind, humidity profiles
AIREPAircraft dataTemperature, wind profiles
AMDARAircraft dataTemperature, wind profiles
ACARSAircraft dataTemperature, wind profiles, humidity
WIGOS AMDARAircraft dataTemperature, wind profiles
Ground based radarRadar precipitation compositesRain rates

Snow data

Dataset nameObservation typeMeasurement
SYNOPLand stationSnow depth
Additional national reportsLand stationSnow depth
NOAA/NESDIS IMSMerged satelliteSnow cover (NH only)

Guidelines

The following advice is intended to help users understand particular features of the ERA5 data:

  • Sea surface temperature and sea-ice cover (see Table 2 above) are available at the usual times, eg hourly for the HRES, but their content is only updated once daily.
  • Mean rates and accumulations at step=0 have values of zero because the length of the processing period is zero.

Known issues

Currently, we are aware of these issues with ERA5:

  • ERA5 suffers from an overly strong equatorial mesospheric jet, particularly in the transition seasons.

  • From 2000 to 2005, ERA5 has a poor fit to radiosonde temperatures in the stratosphere, with a cold bias in the lower stratosphere and a warm bias higher up.

  • ERA5 uncertainty: although small values of ensemble spread correctly mark more confident estimates than large values, numerical values are over confident. The spread does give an indication of the relative uncertainty in space and time.

  • Discontinuities in ERA5: ERA5 is produced by several parallel experiments, each for a different period, which are then appended together to create the final product. This can create discontinuities at the transition points.
  • The Potential Evaporation field (pev, parameter Id 228251) is largely underestimated over deserts and high-forested areas. This is due to a bug in the code that does not allow transpiration in case no low vegetation type is present.
  • The hourly data reveals a mismatch in the analysed near surface wind speed between the end of one assimilation cycle and the beginning of the next (which occurs at 9:00 and 21:00 UTC). This problem mostly occurs in low latitude oceanic regions, though it can also be seen over Europe and the USA. The forecast near surface winds show much better agreement between the assimilation cycles, at least on average, so our advice would be to use the forecast winds. We cannot rectify the problem in the analyses.
  • Wind values are far too low on pressure levels at the poles in the Climate Data Store (CDS)
  • Prior to 2014, the SST was not used over the Great Lakes to nudge the lake model. Consequently, the 2 metre temperature  has an annual cycle that is too strong, with temperatures being too cold in winter and too warm in summer.
  • ERA5 large 10m winds: a few times per year, the analysed low level winds, eg 10m winds, become very large in a particular location, which varies amongst a few apparently preferred locations. The largest values seen so far are about 300 ms-1.

Resolved issues

How to cite ERA5

Please acknowledge the use of ERA5 as stated in the Copernicus C3S/CAMS License agreement:

  • "5.1.2 Where the Licensee communicates or distributes Copernicus Products to the public, the Licensee shall inform the recipients of the source by using the following or any similar notice:

    'Generated using Copernicus Climate Change Service Information [Year]'.

  • 5.1.3 Where the Licensee makes or contributes to a publication or distribution containing adapted or modified Copernicus Products, the Licensee shall provide the following or any similar notice:

    'Contains modified Copernicus Climate Change Service Information [Year]';

5.1.3 Any such publication or distribution covered by clauses 5.1.1 and 5.1.2 shall state that neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus Information or Data it contains."

You may also cite the ERA5 dataset as follows:

Dataset citable as: Copernicus Climate Change Service (C3S) (2017): ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate . Copernicus Climate Change Service Climate Data Store (CDS), date of access. https://cds.climate.copernicus.eu/cdsapp#!/home

References

Operational global reanalysis: progress, future directions and synergies with NWP

Further ERA5 references are available from the ECMWF e-Library.