Description of the upgrade

The new cycle includes a collection of improvements to the forecast model and the data assimilation system, affecting the high-resolution forecasts and analyses, the ensemble of data assimilations (EDA) and the ensemble prediction system including its monthly extension.

Implemented: 19 June 2012  


Unchanged from previous IFS cycle.


Atmospheric (unchanged)

  • HRES: T1279
  • ENS: Leg A T639, Leg B T319, Leg C T255
Wave (unchanged)
  • HRES: 0.25 degrees
  • ENS: 0.5 degrees
Atmospheric (unchanged)
  • HRES: L91
  • ENS: L62
  • SEAS: L91

Meteorological content

  • Updated background-error covariance statistics (for Jb) based on the cycle 37r2 EDA
  • Improved statistical filtering of EDA sampled background errors.
  • Assimilation of MHS channel 5 over land and the all-sky radiance product from SEVIRI on board Meteosat-9 (the OSCAT scatterometer data on board the Indian Oceansat-2 satellite will be monitored)
  • Modified convective downdraught entrainment
  • Changes to cloud ice fall speed, ice supersaturation, melting of ice to rain and freezing timescale of rain
  • Improved de-aliasing of the pressure gradient term, reducing numerical noise, allowing a reduction of the horizontal diffusion in the forecast
  • Improved description of swell
  • Use of a new surface reanalysis to initialize the surface fields in the EPS hindcasts
  • Extension of the EPS hindcast years from 18 to 20, all based on ERA-interim initial data
  • EDA perturbations redefined using the EDA ensemble mean instead of the EDA control as the reference

Meteorological impact

  • High-resolution forecast performance
  • EPS forecast performance
  • Impact on the model climate
  • Impact of the new soil reanalysis


Scorecard ENS

New and changed parameters

New parameters


Changes to existing parameters


Technical content

  • Changes to GRIB headers
  • The Extreme Forecast Index (EFI)
  • New model output parameters

Model ID and experiment number

Model ID = 38r1

E-suite experiment number = 0058


ECMWF Newsletter: See Newsletter 132