Atmospheric general circulation component

Table 1a: Key characteristics  of the atmospheric component of the IFS based on Cycle 49r1

 

Forecast / Analysis

Number of members

Horizontal resolution

Vertical levels

Pressure at model top (hPa)

Perturbation models

CTRL (former HRES)

Atmospheric Model control forecast

Forecast

  • 0–15 days

1

  •  Native  (1):   O1280  ~9km
  •  Interpolated  (2):  0.1°  ~9km

137

0.01 hPa

No

ENS

Ensemble - Atmospheric Model

Forecast

  • 0–15 days
51
  • Native  (1):  O1280 ~9km
  • Interpolated  (2):0.1°
1370.01 hPa

Yes  (4)

ENS Sub-seasonal

Atmospheric Model Sub-seasonal forecast

Forecast

  • 0–46 days
  • once a day at 00 UTC
51
  • Native (1):   O320  ~36km
  • Interpolated  (2):  0.4°


137

0.01 hPaYes  (4)

4DVAR

4-Dimensional data assimilation

Analysis

1

  •   N255/N319/N399/N399  inner loop minimisations
  • 4 outer loops at  O1280  resolution


137


0.01 hPa

No

EDA

Ensemble of data assimilations

Analysis

51

  •  N191/N191  inner loop  minimisations
  • 2 outer loops at  O1280  resolution 

137

0.01 hPa

Yes  (5)

SEAS5  2017 version   Cycle 43r1

Seasonal forecast

Forecast

  • long-range forecast run monthly from 0 to 7 months
  • annual range forecast run quarterly from  0 to 13 months

51


15

  • Native  (1):O320 ~36km
  • Interpolated  (2): 0.4°

91

0.01 hPa

Yes  (4)

Ensemble and seasonal re-forecasts

Table 1b: Key characteristics of the ENS and SEAS re-forecasts of the ECMWF IFS

 

Forecast/Analysis

Number of members

Horizontal resolution

Vertical levels

Pressure at model top (hPa)

Perturbation models

Number of years

ENS medium range

  • 0–15 days
  • runs of 1/5/9/13/17/21/25/29 of the month 
    (excluding 29 February)
11
  • Native  (1):  O640
  • Interpolated  (2): 0.25° ~28km
1370.01 hPaYes  (4)Most recent 20

ENS sub-seasonal range

  • 0–46 days
  • runs of  1/3/5/7/9/11/13/15/17/19/21/23/25/27/29/31
    of the month (excluding 29 February)
11
  • Native (1):   O320  ~36km
  • Interpolated  (2):  0.4°

 

1370.01 hPaYes  (4)Most recent 20

SEAS5    Cycle 43r1

Seasonal forecast

Forecast

  • run monthly
  • 0–7 months (monthly)


  • run quarterly 0-13 months (annual range)


25


15

  • Native  (1):O320 ~36km
  • Interpolated  (2): 0.4°

91


0.01 hPaYes  (4)36 (1981-2016)

Ocean general and sea ice

Table 1c: Key characteristics of the ocean component general circulation models of the ECMWF IFS

 

Forecast/Analysis

Number of members

Horizontal resolution

ORCA grid

Vertical levels

NEMO (LIM-2)

Forecast

  • daily (HRES and ENS)
  • run monthly
  • 0–7 months (monthly)
  • run quarterly 0-13 months (annual range)

51

0.25°

75

Oceans

  • OCEANS-BRT (Behind Real-Time)
  • OCEANS-RT (Real-Time)

Analysis

Reanalysis

5

0.25°

75

Ocean-wave component

Table 1d: Key characteristics of the ocean-wave component of the ECMWF IFS


Forecast/AnalysisDomainNumber of membersHorizontal resolution

CTRL-WAM

Ocean Wave  coupled  to the atmospheric model

Analysis and forecast

  • 0–15 days
Global1
  • Native  (1):   O1280  ~9km
  • Interpolated  (2):  0.1°  ~9km

ENS-WAM medium range

Ensemble wave medium range forecast

Forecast

  • 0-15 days
Global51
  • Native  (1):  O1280 ~9km
  • Interpolated  (2): 0.1°

ENS-WAM sub-seasonal range

Ensemble wave sub-seasonal forecast

Forecast

  • 0-46 days
Global51
  • Native (1):   O320  ~36km
  • Interpolated (2):  0.4°

SEAS-WAM

Seasonal wave forecast

Forecast

  • run monthly
  • 0–7 months (monthly)
  • run quarterly 0-13 months (annual range)
Global51
  • Native (1):   O320  ~36km
  • Interpolated (2):  0.4°

Atmospheric and Ocean-wave reanalysis  ERA5

ERA5, based on  IFS Cycle 41r2, is used to initialise ensemble reforecasts. 


Forecast/Analysis

Number of members

Horizontal resolution

Vertical levels

Pressure at model top (hPa)

Perturbation models

ERA5

Atmospheric high resolution reanalysis

  • Analysis
  • Forecast


1
  • ~ 31km, 0.28125 degrees (at the equator)
  • Depending on the parameter, the data are archived either as spectral coefficients with a triangular truncation of T639 or on a reduced Gaussian grid with a resolution of N320.
1370.01No

ERA5  EDA

Atmospheric reduced resolution ensemble

  • Analysis
  • Forecast
10
  • ~ 63km, 0.5625 degrees (at the equator)
  • Depending on the parameter, the data are archived either as spectral coefficients with a triangular truncation of T319 or as N160 reduced Gaussian grid.
1370.01Yes  (5)

ERA5  wave

Ocean wave model (WAM) reanalysis

  • Analysis
  • Forecast
1

0.36 degrees

1-No

ERA5 wave  EDA

Ocean wave reduced resolution ensemble

  • Analysis
  • Forecast
101.0 degrees1-Yes  (5)

 4D-Var data available for all the 4 entries.
 

(1)  Native: as produced by the model on reduced Gaussian grids or spherical harmonics.

(2)  Interpolated to lat/lon

(3)  Native: as produced by the model on reduced lat/lon grids.

(4)  in analysis and model physics

(5)  in observations and model physics

1 Comment

  1. Kathy Maskell

    This page of information was previously on the website under the 'About our forecasts' section.  Working with Tim Hewson, Helen Setchell, David Armstrong and Hilda Carr, the 'About our forecasts' web content was updated in March 2023 and this page of information about forecast configurations was felt to fit better on confluence, within the Forecast User space.