Cycle 33r1 summary of changes

Implementation date

3 June 2008

See Newsletter No.116
IFS Documentation CY33R1  
Key characteristics of our current forecasting system  


  • Atmospheric
    • HRES: TL799
    • ENS: Leg A TL399
  • Wave
    • HRES: 0.25 degrees
    • ENS: 0.5 degrees
    • LAW: 0.1 degrees (was 0.25)

Vertical (unchanged)

  • Atmospheric
    • HRES: L91
    • ENS: L62
Data set affected
  • ENS
  • Limited wave model area
Score card
  • modest but significant positive impact on northern hemisphere and European scores in the troposphere
  • similar results were obtained for three weeks of ENS testing
Meteorological changes
  • Improved moist physics in tangent linear/ adjoint model used in 4D- Var assimilation.
  • Re-tuned entrainment in convection scheme.
  • Bug fix to scaling of freezing term in convection scheme.
  • Additional shear term in diffusion coefficient of vertical diffusion.
  • Increased turbulent orographic form drag.
  • Fix for soil temperature analysis in areas with 100% snow cover.
  • Change in surface roughness for momentum, and change in post-processing of two-metre temperature and specific humidity.
  • Assimilation of AMSR-E and TMI radiances in 1D+4D-Var; assimilation OMI ozone data.
  • Usage of all four wind solutions for QuikSCAT in assimilation, rather than only two previously.
  • Extended coverage and increased resolution for the limited area wave model.
  • Improved shallow water physics and modified advection scheme for ocean wave models.
  • Introduction of two new wave model parameters: maximum wave height and corresponding wave period.
Meteorological impacts  
Technical changes  -
Model ID
  • Atmospheric: 132
  • Ocean wave: 117
  • Limited-area ocean wave: 217
New disseminated model output -  
Discontinued disseminated model output -  
e-suite experiment number 0037