Description of the upgrade

ECMWF introduced an extra set of product fields in order to address an issue that occurs at day 10 in accumulated fields of the ensemble forecast (ENS). The additional products are available through dissemination under the name Ensemble Forecast Overlap (EFOV).

The issue was caused by the change in ENS horizontal resolution from higher resolution in leg 1 (0 to 240 hours) to lower resolution in leg 2 (246 to 360 hours). The change in resolution creates incorrect values for accumulations that run across day 10, i.e. those that span forecast time steps 240-246 hours.

Implemented: 21 November 2012  

The full list of ensemble forecast overlap fields available

Surface runoff (variable resolution)srovarm230008
Sub-surface runoff (variable resolution)ssrovarm230009
Total sky direct solar radiation at surface (variable resolution)fdirvarJ m**-2230021
Clear-sky direct solar radiation at surface (variable resolution)cdirvarJ m**-2230022
Stratiform precipitation (Large-scale precipitation) (variable resolution)lspvarm230142
Convective precipitation (variable resolution)cpvarm230143
Snowfall (convective + stratiform) (variable resolution)sfvarm of water equivalent230144
Boundary layer dissipation (variable resolution)bldvarJ m**-2230145
Surface sensible heat flux (variable resolution)sshfvarJ m**-2230146
Surface latent heat flux (variable resolution)slhfvarJ m**-2230147
Surface solar radiation downwards (variable resolution)ssrdvarJ m**-2230169
Surface thermal radiation downwards (variable resolution)strdvarJ m**-2230175
Surface net solar radiation (variable resolution)ssrvarJ m**-2230176
Surface net thermal radiation (variable resolution)strvarJ m**-2230177
Top net solar radiation (variable resolution)tsrvarJ m**-2230178
Top net thermal radiation (variable resolution)


J m**-2230179
East-West surface stress (variable resolution)ewssvarN m**-2 s230180
North-South surface stress (variable resolution)nsssvarN m**-2 s230181
Evaporation (variable resolution)evarkg m**-2230182
Sunshine duration (variable resolution)sundvars230189
Longitudinal component of gravity wave stress (variable resolution)lgwsvarN m**-2 s230195
Meridional component of gravity wave stress (variable resolution)mgwsvarN m**-2 s230196
Gravity wave dissipation (variable resolution)gwdvarJ m**-2230197
Skin reservoir content (variable resolution)srcvarkg m**-2230198
Runoff (variable resolution)rovarm230205
Total precipitation (variable resolution)tpvarm230228

Further reading

  • A comprehensive description of the Ensemble system and its variable resolution (leg 1 and leg 2) can be found in Newsletter 108 (pp 14-20).

Changes in GRIB API

Support for two following parameters was added to GRIB API.
  • fdirvar = Total sky direct solar radiation at surface (variable resolution)
  • cdirvar = Clear-sky direct solar radiation at surface (variable resolution)