The ECMWF Integrated Forecasting System (IFS)

See also:

Summary of the key characteristics of the IFS. Operational configurations of the ECMWF Integrated Forecasting System (IFS)

Implementation of Atmospheric model CY49R1

Documentation Atmospheric model CY48R1

Documentation Ocean model

ERA ERA-Interim, ERA5, ERA5-Land

Model	Function	System Name	Resolution & Levels (follow links to see where the model levels are)	Ensemble Size	Top Level
Atmospheric General Forecast Model	Ensemble Control Forecast	Ensemble Control Forecast	~9km 137 levels (T_Co1279)	1	0.01 hPa
	Medium range	ENS	~9km 137 levels (T_Co1279)	50	0.01 hPa
	Sub-seasonal	Sub-seasonal ENS	~36km 137 levels (T_Co319)	100 + Control	0.01 hPa
	Seasonal (run monthly for months 0-7)	Seasonal ENS	~36km 91 levels (T_Co319)	50 + Control	0.01 hPa
	Seasonal (run quarterly for months 0-13)	Seasonal ENS	~36km 91 levels (T_Co319)	15	0.01 hPa
	Oceanic wave model ensemble (Medium Range)	Ensemble Control (HRES WAM) Medium range ENS WAM	~9km	1 50
	Oceanic wave model ensemble (Sub-seasonal)	Sub-seasonal ENS WAM	~36km	50
	Seasonal wave model ensemble	Seasonal WAM	~1 deg lat x 1 deg long

	Atmospheric model Reanalysis Re-forecast	ERA5 Ensemble Control (ex-HRES) ENS	~9km 137 levels (archived at T_Co1279)	10	0.01 hPa
	Atmospheric model Reanalysis Re-forecast	ERA5 Sub-synoptic ENS	~36km 137 levels (archived at T_Co319)	10	0.01 hPa
	Atmospheric model Ensemble of Data Assimilations (EDA) Reanalysis	ERA5 EDA	~18km 137 levels (archived at T_Co639)	50	0.01 hPa
	Oceanic wave model Reanalysis Re-forecast	ERA5 Wave	0.36° Latitude	1
	Oceanic wave model EDA Reanalysis	ERA5 Wave EDA	1.00° Latitude	10

Parameterised systems for 2-way interaction with Atmospheric Model Resolution same as the calling model... ...unless otherwise shown	Land Surface Model (LDAS)	HTESSEL
	Sea Surface Model (WAM) (See below)	WAM
	Lake Model	FLAKE
	Convection Model	CONV
	Clouds - Large Scale Water Processes	LSWP
	Radiation	RDTT	Ensemble Control Forecast and Medium Range Ensemble ~55km Seasonal Ensemble ~222km
	Turbulence & Gravity Wave Drag	TGWD
	Non-orographic Gravity Wave Drag	NOGW
	Sea Ice Model (see NEMO below)	LIM2
	Representation of uncertainty in parameterisation schemes	SPPT
	Representation of uncertainty in energy transfer... ...from sub-gridscales to resolved scales	SKEB

Table 12.A.2 Main Oceanographic Models and Programmes

Model	Function	System Name	Resolution	Ensemble Size
Wave forecast model	Ocean wave coupled to Ensemble Control	HRES-WAM Ensemble Control	~9km.	1
	Ocean wave coupled to Sub-seasonal	ENS-WAM	~9km.	50 + Control
	Ocean wave coupled to Seasonal	SEAS-WAM	~36km.	50 + Control

Model

Function

System Name

Resolution

Ensemble Size

Ocean General Circulation Model

NEMO

~28km. 0.25° Latitude

75 levels

50

+ control

Sea Ice Model

SI³

~28km. 0.25° Latitude

Table 12.A.3 Data Assimilation Programmes

Assimilation Programmes	System Name	System Name	Resolution & Levels	Ensemble Size	Top Level
Atmospheric Data Assimilation Series of nested loops at increasing resolutions	4D-Var	4D-Var	137 levels	1	0.01 hPa
Ensembles of Data Assimilation Series of nested loops at increasing resolutions	4D-Var	EDA	137 levels	50 + Control	0.01 hPa
Ocean Real Time Analysis	NEMOVAR	ORTS6	~28km 75 levels	1
Ensembles of Data Assimilation for Ocean Model Ensemble.	NEMOVAR	ORAS6	~28km 75 levels	5

Indicators for Resolution:

TL Triangular-linear grid (shortest wave resolution is represented by two grid points).
T_Co Triangular-cubic-octahedral grid (shortest wave resolution is represented by four grid points).
N Native grid, as produced by the model on reduced Gaussian grids or spherical harmonics.

The numbers indicate the spectral truncation.

(FUG Associated with Cy50r1)