Page History

The resolution of one-week ensemble prediction model of JMA was upgraded on 21 November 2007.

Major changes are:

• Increase in the resolution from TL159L40 to TL319L60 with a topmost level raised from 0.4hPa to 0.1hPa.
• Use of a new high-resolution analysis of sea surface temperature and sea ice concentration as ocean surface boundary conditions.
• Use of surface snow depth data from the domestic dense observational network in the global snow depth analysis.
• Introduction of a convective triggering scheme into the deep convection parameterization.
• Introduction of a new 2-dimensional aerosol climatology derived from satellite observations for the radiation calculation.
• Increase in the resolution of inner loop model of the four-dimensional variational (4D-Var) data assimilation system from T106L40 to T159L60.
• Introduction of a sigular vector method to make the initial perturbations.

Notes:

• The resolution and parameters of TIGGE data from JMA remains unchanged.
• Orography and Land Sea Mask in TIGGE data are slightly different from the previous data associated with the model change.

UM upgraded to version PS39 from 12UTC cycle on 11 July 2017.

TIGGE global ensemble (the Met Office MOGREPS-G) was upgraded to 20km (from 33km), N640L70, 280x960 lat-long grid, 0.1875 N-S x 0.28125 E-W degrees;  the MOGREPS-G will continue to run four times a day (00, 06, 12 and 18UTC), but the number of ensemble members per run has increased from 12 to 18, with the last two runs being combined to create a 36-member time-lagged ensemble.

Forecast length remains at 7d 6h.

Relevant associated deterministic/data assimilation changes:

• Replace RTTOV9 by RTTOV11
• New ground GPS observation operator
• Improved snow analysis reconfiguration
• Upgrade to UM10.6