Cycle 32r3 summary of changes

Implementation date

6 November 2007

 
Key characteristics of our current forecasting system  
Resolution

Horizontal  (unchanged)

  • Atmospheric
    • HRES: TL799
    • ENS: Leg A TL399
  • Wave
    • HRES: 0.36 degrees
    • ENS: 0.5 degrees
    • LAW: 0.1 degrees

Vertical (unchanged)

  • Atmospheric
    • HRES: L91
    • ENS: L62
Data set affected
  • HRES
  • ENS
Meteorological changes
  • New formulation of convective entrainment and relaxation timescale
  • Reduction in free atmosphere vertical diffusion
  • New soil hydrology scheme
  • New radiosonde temperature and humidity bias correction
  • Increase in number of radio occultation data from COSMIC
  • Assimilation of AMSR-E, TMI, SSMIS window channels (clear sky)
  • Assimilation of SBUV ( NOAA-17, NOAA-18) and monitoring of OMI ozone data
  • Corrections to the radiation post-processing in the IFS will correct/improve the following parameters:
    • 57 (UVB) Downward UV radiation at the surface
    • 58 (PAR) Photosynthetically active radiation at the surface
    •  59 (CAPE) Convective available potential energy

ENS

  • initial perturbation amplitude reduced by 30%
  • singular vectors targeted on tropical cyclones are computed with the new moist physics package in the tangent-linear and adjoint models (as used in the operational in 4D- Var since cycle 32r2).

 

Meteorological impacts
  • improved scores for the extra-tropical southern hemisphere throughout the forecast range, and for the northern hemisphere in the first half of the forecast
  • substantial improvement to the lower tropospheric winds in the tropics compared to observations
  • reduction in the biases of 2m temperature mainly over the Americas
  • improved precipitation forecasts over Europe

ENS

  • reduction of the initial perturbation amplitude resulted in a good match of spread and ensemble mean error
  • probabilistic skill is generally improved at mid-latitudes
  • improved reliability of the tropical cyclone strike probability forecasts
  • neutral impact in the extra-tropics
  • beneficial impact on probabilistic precipitation forecasts over Europe.
Technical changes  
Model ID
  • Atmospheric: 130
  • Ocean wave: 116
  • Limited-area ocean wave: 216
 
New disseminated model output Four new pressure levels in the analyses and HRES forecast runs: 600, 800, 900 and 950 hPa.  
Discontinued disseminated model output -  
e-suite experiment number 0035