Changes in ECMWF model

Evolution of the IFS

The comprehensive Earth system model developed at ECMWF forms the basis for all the data assimilation and forecasting activities. All the main applications required are available through one integrated computer software system (a set of computer programs written in Fortran) called the Integrated Forecasting System or IFS.

The IFS undergoes changes regularly in order to improve the forecast. Changes are listed below with their identifier (Cycle 32r1 for instance) or a specific title when the cycle number did not change.

Implementation date

Summary of changes

ResolutionFull IFS documentation
12-Oct-2021  Cycle 47r3Unchanged  CY47R3
11-May-2021Cycle 47r2ENS (Vertical)as CY47R1
30-Jun-2020Cycle 47r1UnchangedCY47R1
11-Jun-2019Cycle 46r1UnchangedCY46R1
05-Jun-2018Cycle 45r1UnchangedCY45R1
05-Nov-2017Implementation of Seasonal Forecast SEAS5UnchangedDocumentation
11-Jul-17Cycle 43r3 UnchangedCY43R3
22-Nov-16Cycle 43r1Ocean (Horizontal & vertical)CY43R1

Cycle 41r2

HRES/ENS/WAVE (Horizontal)

12-May-15Cycle 41r1UnchangedCY41R1
1-Dec-13Tropical cyclone trajectoryUnchanged 
19-Nov-13Cycle 40r1ENS (Vertical)CY40R1
26-Jun-13Cycle 38r2HRES (Vertical) 
21-Nov-12Ensemble forecast overlapUnchanged 
19-Jun-12Cycle 38r1UnchangedCY38R1
15-Nov-11Cycle 37r3Unchanged 

Seasonal Forecast System 4

SEAS (Horizontal & Vertical) 
18-May-11Cycle 37r2UnchangedCY37R2
8-Mar-11New ENS ClusterUnchanged 
09-Nov-10Cycle 36r4Unchanged 
24-Jun-10Cycle 36r2Unchanged 
26-Jan-10Cycle 36r1HRES/ENS/Ocean (Horizontal)CY36R1
13-Oct-09LAW resolution increaseLAW 
08-Sep-09Cycle 35r3Unchanged 
10-Mar-09Cycle 35r2Unchanged 
30-Sep-08Cycle 35r1/ 33r2Unchanged 
03-Jun-08Cycle 33r1LAWCY33R1
11-Mar-08Cycle 32r3VUnchanged 
06-Nov-07Cycle 32r3Unchanged 
05-Jun-07Cycle 32r2Unchanged 
12-Dec-06Cycle 31r2Unchanged 
12-Sep-06Cycle 31r1UnchangedCY31R1
01-Feb-06Cycle 30r1Changed 

Older Upgrades


IdentifierResolutionIFS Documentation
28-Jun-05Cycle 29r2Unchanged 
05-Apr-05Cycle 29r1Unchanged 
28-Sep-04Cycle 28r3Unchanged 
29-Jun-04Cycle 28r2Unchanged 
09-Mar-04Cycle 28r1UnchangedCY28R1
07-Oct-03Cycle 26r3Unchanged 
29-Apr-03Cycle 26r1Unchanged 
04-Mar-03Cycle 25r5Unchanged 
14-Jan-03Cycle 25r4Unchanged 
09-Apr-02Cycle 25r1UnchangedCY25R1
22-Jan-02Cycle 24r3Unchanged 
12-Jun-01Cycle 23r4Unchanged 
21-Nov-00Cycle 23r3HRES (Horizontal) 
12-Sep-00Cycle 23r1Unchanged 
27-Jun-00Cycle 22r3Unchanged 
11-Apr-00Cycle 22r1Unchanged 
12-Oct-99Cycle 21r4HRES (Vertical) 
13-Jul-99Cycle 21r2Unchanged 
05-May-99Cycle 21r1Unchanged 
09-Mar-99Cycle 19r2HRES (Vertical) 
1998 summary of changesCycles 19r1, 18r6, 18r5, 18r4HRES (Horizontal) 

1997 summary of changes

Cycles 18r3, 18r1,16r4,16r2, 15r8Unchanged 
1996 summary of changesCycles 15r7, 15r5, 14r3Unchanged 
1995 summary of changesCycle 13r4Unchanged 
1994 summary of changesCycles 12r1, 11r7Unchanged 
1993 summary of changesCycles 49, 48, 47, 46Unchanged 
1992 summary of changesCycles 45, 44, 43, 42, 41Unchanged 
1991 summary of changesCycles 40, 39, 38HRES (Horizontal & vertical) 
1991 summary of changesCycles 36 35Unchanged 

1989 summary of changes

Cycles 34, 33, 32Unchanged 
1988 summary of changesCycles 31, 30Unchanged 
1987 summary of changesCycles 29Unchanged 
1986 summary of changesCycles 28, 27, 26HRES (Vertical) 
1985 summary of changesCycles 25, 24, 23, 22HRES (Horizontal)