84th AMS Annual Meeting

Tuesday, 13 January 2004: 11:30 AM
Global ensemble forecast at NCEPóconfiguration, implementation and plan
Room 6A
Yuejian Zhu, NOAA/NWS/NCEP, Camp Springs, MD; and Z. Toth, R. Wobus, and M. Wei
In April 2003, the amplitude of initial perturbations in the regional rescaling algorithm of the breeding technique used in the generation of global ensemble forecasts at NCEP was updated to better reflect analysis uncertainty. The amplitudes decreased substantially over the SH and Tropics, and slightly over the NH. In August 2003, by adding new ensembles of 10 members each at 06 UTC and 18 UTC, the total numbers of ensemble members for 24-hours cycle is increased to 40. The effect of this change on the performance of the system will be evaluated in terms of different verification measures. Other expected changes, such as an increase in the horizontal resolution, membership will be discussed. The current breeding technique and Ensemble Transform Kalman Filter (ETKF) scheme will be compared.

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