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Operational configurations of the ECMWF Integrated Forecasting System (IFS)

These tables summarise the key characteristics of the ECMWF IFS model, offering links to documentation on data descriptions, graphical products, cycle information, resolution, etc.

In this page Atmospheric general circulation component Ensemble and Seasonal reforecasts Ocean general circulation component models Ocean-wave component Atmospheric and Ocean-wave reanalysis ERA5	See also Forecast User portal (IFS Forecasting Issues, Severe Event Catalogue, ...) ECMWF Forecast User Guide IFS Documentation Data Services Knowledge Base

In this page

Atmospheric general circulation component
Ensemble and Seasonal reforecasts
Ocean general circulation component models
Ocean-wave component
Atmospheric and Ocean-wave reanalysis ERA5

See also

Forecast User portal (IFS Forecasting Issues, Severe Event Catalogue, ...)
ECMWF Forecast User Guide
IFS Documentation
Data Services Knowledge Base

Atmospheric general circulation component

Table 1a: Key characteristics of the atmospheric component of the ECMWF IFS (Based on the latest IFS cycle, 47r3)
	Forecast / Analysis	Number of members	Horizontal resolution	Vertical levels	Pressure at model top (hPa)	Perturbation models
HRES Atmospheric Model high resolution Data Graphical products Documentation	Forecast 0–10 days	1	Native ⁽¹⁾: O1280 ~9km Interpolated ⁽²⁾: 0.1° ~9km	137	0.01 hPa	No
ENS Ensemble - Atmospheric Model Data Graphical products Documentation	Forecast 0–15 days	51	Day 0-15 Native ⁽¹⁾: O640 ~18km Interpolated ⁽²⁾:0.2°	137	0.01 hPa	Yes⁽⁴⁾
ENS Extended Atmospheric Model Extended forecast (monthly) Data Graphical products Documentation	Forecast 16–46 days run twice a week	51	Native (1): O320 ~36km Interpolated ⁽²⁾: 0.4°	137	0.01 hPa	Yes ⁽⁴⁾
4DVAR 4-Dimensional data assimilation Data (See Analysis in HRES) Graphical products Documentation	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 Data	Analysis	51	N191/N191 inner loop minimisations 2 outer loops at O640 resolution	137	0.01 hPa	Yes ⁽⁵⁾
SEAS5 2017 version Cycle 43r1 Seasonal forecast Data Graphical products Documentation	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 Data Graphical products Documentation	0–46 days run twice a week	11	Day 0-15 Native ⁽¹⁾: O640 Interpolated⁽²⁾: 0.25° ~28km Day 16-46 Native ⁽¹⁾: O320 Interpolated (2): 0.5° ~55km		137	0.01 hPa	Yes ⁽⁴⁾	Most recent 20
SEAS5 Cycle 43r1 Seasonal forecast Documentation	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 hPa	Yes ⁽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/Analysis	Domain	Number of members	Horizontal resolution
HRES-WAM Ocean Wave coupled to the atmospheric model Data Graphical products Documentation	Analysis and forecast 0–10 days	Global	1	Native: 0.125° reduced ⁽³⁾ ~14km Interpolated ⁽²⁾: 0.125°~ 14km
ENS-WAM Ensemble wave forecast Data Graphical products Documentation	Forecast 0-46 days	Global	51	0-15 days Native: 0.25° reduced ⁽³⁾ ~28km Interpolated ⁽²⁾: 0.25° ~28km 16-46 days Native: 0.5° reduced ⁽³⁾ ~55km Interpolated ⁽²⁾: 0.5° ~55km
	Forecast 0-46 days	Global	51
SEAS-WAM Seasonal wave forecast Documentation	Forecast run monthly 0–7 months (monthly) run quarterly 0-13 months (annual range)	Global	51	Native: 0.5° reduced ⁽³⁾ ~55km Interpolated ⁽²⁾: 0.5° ~55km

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 HRES Atmospheric high resolution reanalysis Data Documentation	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.	137	0.01	No
ERA5 EDA Atmospheric reduced resolution ensemble Data Documentation	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.	137	0.01	Yes ⁽⁵⁾
ERA5 wave Ocean wave model (WAM) reanalysis Data Documentation	Analysis Forecast	1	0.36 degrees	1	-	No
ERA5 wave EDA Ocean wave reduced resolution ensemble Data Documentation	Analysis Forecast	10	1.0 degrees	1	-	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