Integrated Forecasting System - IFS

The ECMWF Integrated Forecasting System (IFS) consists of several components coupled together in various different ways:

These are outlined in Fig2-1, Fig 2-2 and Fig2-3.  The models and programs run co-operatively to produce forecasts from analysis time out to days, weeks or months ahead.


Fig2-1:  ECMWF Integrated Forecasting System (IFS) Illustrates interactions between components of the IFS (observation assimilation and post-processing not shown)


Fig2-2: Exchange of physical quantities between the atmospheric, ocean wave and ocean models.  All the models exchange information and additionally the Wave model gains from the Ice model information on ice cover.


Exchange of physical quantities between the atmospheric, ocean wave and ocean models. 

The Atmospheric models give:

The Wave model gives:

The Ocean model gives:

The Ice Model gives:


Fig2-3:  ECMWF Coupling sequence and exchange of physical quantities between the atmospheric, ocean wave and ocean models.


Atmospheric Models are coupled with the Wave Model (ECWAM) and the Ocean Model (NEMO) because:

Atmospheric Models are coupled with HTESSEL and FLake because:

The coupled model configuration is used with:

More information is given within the Users Guide on the structures of the Global Atmospheric Model, the Ocean Wave Model, and the Dynamic Ocean Model and regarding the resolution of the models currently used within the IFS.

Real-time forecasts are initialized from the operational analysis using 4D-Var.  Re-forecasts are initialized from ERA5, except for soil initial conditions (soil temperature, soil moisture, snow initial conditions) which are provided by an offline soil reanalysis.  Oceanic models are initialized from the real-time suite, NEMOVAR.