Detailed model description

Page containing details for all model configurations available in S2S since the project start =>ECMWF model description

Overview of the model changes

 Model version

Implementation

Date in S2S

Time range
Atmosphere
Resolution
Ens. Size
Frequency
Rfc type
Rfc length

Rfc frequency

Rfc size

Ocean

Resolution

Active Sea IceRemarks
CY50R113/05/2026d 0-46

Tco319L137 (about 32 km) 

101

daily

on the flypast 20 years

1/3/5/7/9/11/13/15/17/
19/21/23/25/27/29/31 of each month (excluding 29 February)

111/4 degreeYesNew ocean and sea ice models based on NEMO4-SI 3
CY49R112/11/2024d 0-46

Tco319L137 (about 32 km) 

101

daily

on the flypast 20 years

1/3/5/7/9/11/13/15/17/
19/21/23/25/27/29/31 of each month (excluding 29 February)

111/4 degreeYesCAPE replaced by  MUCAPE
CY48R127/06/2023d 0-46

Tco319L137 (about 32 km) 

101

daily

on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY47R313/10/2021d 0-46

Tco639 L137 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)		on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY47R211/05/2021d 0-46

Tco639 L137 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)		on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY47R130/06/2020d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15 day 15 L91

51

2/week

(Mon/Thu)		on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes

6-hourly 10u/v added since  

CY46R111/06/2019d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)

on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes

additional ocean parameters  added since 2020/01/02

CY45R106/06/2018d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)

on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY43R3

11/07/2017

d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)

on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY43R122/11/2016d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)

on the flypast 20 years

2/week

(Mon/Thu)

111/4 degreeYes
CY41R208/03/2016d 0-46

Tco639 L91 (about 16 km) up to day 15 and Tco319 (about 32 km) after day 15

51

2/week

(Mon/Thu)

on the flypast 20 years

2/week

(Mon/Thu)

111 degreeNo
CY41R114/05/2015d 0-46

TL639 L91 (about 32 km) up to day 10 and TL319 (about 64 km) after day 10 

51

2/week

Mon/Thu		on the flypast 20 years

2/week

(Mon/Thu)

111 degreeNo
CY40R101/01/2015d 0-32TL639 L91 (about 32 km) up to day 10 and TL319 (about 64 km) after day 10 51

2/week

(Mon/Thu)

on the flypast 20 years

once a week

(Thu)

5 1 degreeNo

Description of the main changes

For the full details refer to the official IFS documentation

information about planned changes to the IFS forecasting system and documentation describing previous changes can be found in Changes to the forecasting system

CY50r1

The ECMWF model has been upgraded to the version 50r1 with major changes among many others:

  • New ocean and sea ice models based on NEMO4-SI 3
  • Updates of the wave model including: new wave interaction with sea ice and ocean currents and revised wave model bathymetry
  • Modified Stochastically Perturbed Parametrisation (SPP) configuration to reduce 10-metre wind spread in the ensemble
  • New ocean and sea ice ensemble analysis system & outer loop coupling of ocean/sea-ice
  • Reintroduction of stratospheric humidity assimilation from radiosondes up to 60 hPa
  • Weak constraint formulation extended to the boundary layer allowing the increased use of T2m observations 

The are no changes to S2S contribution from ECMWF.
The first realtime forecasts and on-the-fly reforecasts runs with the new cycle were on 13/05/2026
More details can be found in ECMWF Model and Implementation of IFS Cycle 50r1 

CY49r1

The IFS Cycle 49r1, will bring major changes to the IFS model and data assimilation system, including among many others:

  • assimilation of 2m temperature observations, 
  • Land-surface model updates,
  • increased resolution and soft-recentering of the ensemble of data assimilations (EDA)  and
  • activation of the stochastically perturbed parameterisations (SPP) model uncertainty scheme in all ensemble configurations. 

Extended-range forecast will change name to sub-seasonal range forecast. This name change will be gradually implemented in the documentation.

The re-forecasts for medium and sub-seasonal forecast systems will see a change in frequency; whilst both will span the past 20 years, as before, they will now be run for fixed days of the month: 

  • medium range every four days: 1/5/9/13/17/21/25/29 (excluding 29 February)
  • sub-seasonal range every two days: 1/3/5/7/9/11/13/15/17/19/21/23/25/27/29/31 (excluding 29 February)

The parameters CAPE (59) and  CIN (228001) are discontinued and replaced by MUCAPE (228235) and MUCIN (228236).

CY48R1

  • increased eps size to 101 for the real-time forecasts
  • the frequency changed to daily for the real-time forecasts since 28/06/2023
  • the same horizontal resolution for the atmosphere Tco319L137 (about 32 km) and the whole forecast range
  • the first reforecasts run with the new cycle on 29/06/2023

2020/01/02  Addition of ocean parameters 

CY43R1

  • changes include increased ocean model resolution to 1/4 degree and active sea-ice
  • operational since  22/11/2016 (included)

CY41R2

  • operational from  8/03/2016 (included) to 22/11/2016 (excluded)

CY41R1

  • changes include extension of re-forecast ensemble size to 11 twice-weekly and forecast length to 46 days
  • operational from 14/05/2015 (included) to 8/03/2016 (excluded)

CY40R1

  • operational before 14/05/2015  (excluded)