Cycle 35r2 summary of change

Implementation date 10 Mars 2009 See Newsletter No.121
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
  • Revised snow scheme including a diagnostic liquid water storage and a new density formulation
  • Revised ozone chemistry
  • Active assimilation of IASI humidity channels and consistent use of AIRS and IASI humidity channels.
  • Activate all-sky 4D-VAR assimilation of microwave imagers
  • Increase of the weight to GPS radio occultation data above 26 km, and use of the data up to 50 km
  • Various satellite-related modifications, including activation of version 9 of the radiative transfer software package RTTOV-9 (developed by NWP-SAF) and revised HIRS cloud detection
  • TL/AD longwave radiation (removal of the neural network), optimization of the non-linear code for simplified longwave radiation and optimization (NL, TL, AD) of the shortwave radiation scheme
  • Extend the domain of the wave model from 81 º to 90 º North
  • Use of ERA-interim analyses for the EFI reforecasts
Meteorological impacts

Overall the new cycle is neutral in terms of verification scores for both hemispheres and the tropics.

  • Improvements to 2m temperature bias and slightly better performance for recent tropical cyclones in both position and intensity.
  • Synoptic performance is generally similar to current operations.
  • Impact on EFI from the change to using ERA-interim analyses for its reforecasts is not substantial.
Technical changes  -
Model ID
  • Atmospheric: 134
  • Ocean wave: 119
  • Limited-area ocean wave: 219
New disseminated model output -  
Discontinued disseminated model output 0042