Description of the upgrade

The new cycle includes important changes to the data assimilation system and a new short-wave radiation scheme.

Implemented: 05 June 2007  

Datasets affected

  • HRES
  • ENS




Atmospheric (unchanged)
  • HRES: TL799
  • ENS: TL399
Wave (unchanged)
  • HRES: 0.36 degrees
  • ENS: 0.5 degrees
  • LAW: 0.1 degrees

Atmospheric (unchanged)
  • HRES: L91
  • ENS: L62

Meteorological content

  • Three-minimization version of 4D- Var assimilation scheme (T95/T159/T255) with improved moist linear physics (cloud and convection)
  • Improved parametrization of the heterogeneous ozone chemistry
  • New short-wave radiation scheme ( RRTM-SW), plus McICA cloud-radiation interaction   and   MODIS albedo
  • Retuned ice particle
  • Revised subgrid-orography scheme
  • Explicit numerical treatment of convection in the moist tangent linear model used in the calculation of tropical singular vectors

Meteorological impact

  • tropical troposphere shows significant improvements at all forecast ranges
  • moderate but statistically significant improvements in the extra-tropical troposphere, particularly in the first four days
  • at 500 hPa the ensemble-mean error is reduced
  • in the tropics the spread at 850 hPa is increased, moving closer to the ensemble-mean error.

Technical content

Model ID and experiment number

  • Atmospheric: 129
  • Ocean wave: 116
  • Limited-area ocean wave: 216

E-suite experiment number = 0034


ECMWF Newsletter: See Newsletter 112