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

Resolution Full IFS documentation
22-Nov-16 Cycle 43r1 (Latest) Ocean (Horizontal & vertical) CY43R1 (in progress)
08-Mar-16

Cycle 41r2

HRES/ENS/WAVE (Horizontal)

CY41R2
12-May-15 Cycle 41r1 Unchanged CY41R1
1-Dec-13 Tropical cyclone trajectory Unchanged  
19-Nov-13 Cycle 40r1 ENS (Vertical) CY40R1
26-Jun-13 Cycle 38r2 HRES (Vertical)  
21-Nov-12 Ensemble forecast overlap Unchanged  
19-Jun-12 Cycle 38r1 Unchanged CY38R1
15-Nov-11 Cycle 37r3 Unchanged  
1-Nov-11

Seasonal Forecast System 4

SEAS (Horizontal & Vertical)  
18-May-11 Cycle 37r2 Unchanged CY37R2
8-Mar-11 New ENS Cluster Unchanged  
09-Nov-10 Cycle 36r4 Unchanged  
24-Jun-10 Cycle 36r2 Unchanged  
26-Jan-10 Cycle 36r1 HRES/ENS/Ocean (Horizontal) CY36R1
13-Oct-09 LAW resolution increase LAW  
08-Sep-09 Cycle 35r3 Unchanged  
10-Mar-09 Cycle 35r2 Unchanged  
30-Sep-08 Cycle 35r1/ 33r2 Unchanged  
03-Jun-08 Cycle 33r1 LAW CY33R1
11-Mar-08 Cycle 32r3V Unchanged  
06-Nov-07 Cycle 32r3 Unchanged  
05-Jun-07 Cycle 32r2 Unchanged  
12-Dec-06 Cycle 31r2 Unchanged  
12-Sep-06 Cycle 31r1 Unchanged CY31R1
01-Feb-06 Cycle 30r1 HRES (Horizontal & Vertical)  

Older Upgrades

Date

Identifier Resolution IFS Documentation
28-Jun-05 Cycle 29r2 Unchanged  
05-Apr-05 Cycle 29r1 Unchanged  
28-Sep-04 Cycle 28r3 Unchanged  
29-Jun-04 Cycle 28r2 Unchanged  
09-Mar-04 Cycle 28r1 Unchanged CY28R1
07-Oct-03 Cycle 26r3 Unchanged  
29-Apr-03 Cycle 26r1 Unchanged  
04-Mar-03 Cycle 25r5 Unchanged  
14-Jan-03 Cycle 25r4 Unchanged  
09-Apr-02 Cycle 25r1 Unchanged CY25R1
22-Jan-02 Cycle 24r3 Unchanged  
12-Jun-01 Cycle 23r4 Unchanged  
21-Nov-00 Cycle 23r3 HRES (Horizontal)  
12-Sep-00 Cycle 23r1 Unchanged CY23R3
27-Jun-00 Cycle 22r3 Unchanged  
11-Apr-00 Cycle 22r1 Unchanged  
12-Oct-99 Cycle 21r4 HRES (Vertical)  
13-Jul-99 Cycle 21r2 Unchanged  
05-May-99 Cycle 21r1 Unchanged  
09-Mar-99 Cycle 19r2 HRES (Vertical)  
1998 summary of changes Cycles 19r1, 18r6, 18r5, 18r4 HRES (Horizontal)  

1997 summary of changes

Cycles 18r3, 18r1,16r4,16r2, 15r8 Unchanged  
1996 summary of changes Cycles 15r7, 15r5, 14r3 Unchanged  
1995 summary of changes Cycle 13r4 Unchanged  
1994 summary of changes Cycles 12r1, 11r7 Unchanged  
1993 summary of changes Cycles 49, 48, 47, 46 Unchanged  
1992 summary of changes Cycles 45, 44, 43, 42, 41 Unchanged  
1991 summary of changes Cycles 40, 39, 38 HRES (Horizontal & vertical)  
1991 summary of changes Cycles 36 35 Unchanged  

1989 summary of changes

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