Cycle 35r1/33r2 summary of changes

Implementation date

30 September 2008

See Newsletter No.120
Key characteristics of our current forecasting system  

Horizontal (unchanged)

  • Atmospheric
    • HRES: TL799
    • ENS: Leg A TL399
  • Wave
    • HRES: 0.25 degrees
    • ENS: 0.5 degrees

Vertical (unchanged)

  • Atmospheric
    • HRES: L91
    • ENS: L62
Data set affected
  • HRES
  • ENS
Meteorological changes
  • The OSTIA (Operational Sea Surface Temperature and Sea Ice Analysis) high-resolution sea surface temperature, produced by the Met Office, and corresponding sea ice analysis (from EUMETSAT Ocean and Sea Ice SAF)
  • Conserving interpolation scheme for trajectory fields in 4D- Var
  • New variational bias correction ( VARBC) bias predictors to allow the correction of infrared shortwave channels affected by solar effects
  • Cleaner cold-start of AMSUA channel 14 bias corrections
  • Changes to physics for melting of falling snow, albedo of permanent snow cover (e.g. over Antarctica), diurnal variation of sea surface temperature, and linear parametrization schemes
  • Convective contribution added to wind gusts in post-processing
  • Monitoring of MERIS total-column water vapour data
  • Neutral scores for the extra-tropics, and improved scores for upper tropospheric winds in the tropics.
  • Improvement in both hemispheres for the late medium range.
Meteorological impacts
  • Improvements to the handling of melting snow as it falls
  • New sea-surface temperature analysis product
    • higher-resolution
    • more frequently updated information, in particular in cloudy situations, based on a range of satellite and in-situ observations.
    • significant ice differences  in the areas with broken ice
    • largest SST differences in the Polar Regions and meanders of the major currents such as the Gulf Stream
Technical changes  -
Model ID
  • Atmospheric: 133
  • Ocean wave: 118
  • Limited-area ocean wave: 218
New disseminated model output -  
Discontinued disseminated model output -  
e-suite experiment number 0040