Cycle 40r1 summary of changes

Implementation date 19 Nov 2013 See Newsletter No.138 p3
IFS Documentation CY40R1  
Detailed description of changes  
Key characteristics of our current forecasting system  

Horizontal (unchanged)

  • Atmospheric
    • HRES: T1279
    • ENS: Leg A T639, Leg B T319, Leg C T255
  • Wave
    • HRES: 0.25 degrees
    • ENS: 0.5 degrees


  • Atmospheric
    • HRES: L137
    • ENS: L91 (prev L62)


Data set affected

  • HRES
  • ENS
Score card Comparison of scores of model cycle 40r1 and cycle 38r2
Meteorological changes
  • Convection
  • Vertical diffusion in stable conditions
  • Turbulent orographic drag
  • Orographic gravity
  • Increase in the surface - atmosphere coupling for forest areas
  • ENS
    • Vertical resolution (from 62 to 91)
    • Atmosphere-ocean coupling now active from initial forecasts time
    • Perturbation of land surface initial conditions
    • Perturbation of land surface temperature
  • Waves
    • Changes to shallow water calculation and surface air density
  • Dynamic estimation of background error covariances for 4DVAR with enhanced 25-members EDA
  • SSMIS 183 GHz channels activated in all-sky microwave radiance assimilation
  • Enhanced use of AMSU-A, AMSU-B and MHS data over sea ice
  • Situation-dependent observation errors and revised quality-control for AMVs
  • Use of calibrated EDA spread in radiance space as background error estimate for the FG-check for ATOVS
Meteorological impacts
  • Upper air
  • Weather parameters
  • Monthly forecast
  • Synoptic aspects
Technical changes
Model ID
  • Atmospheric: 144
  • Ocean wave: 110
  • Limited-area ocean wave: 210
New disseminated model output


Discontinued disseminated model output None
e-suite experiment number 0063 (from 20/08/2013)