EPS operation for
long-range forecasting
JMA's long-range
forecasting model is a coupled ocean-atmosphere general circulation model (CGCM)
type with atmospheric and oceanic initial conditions obtained from the JMA
Climate Data Assimilation System (JCDAS) and MOVE/MRI.COM-G, respectively. Land
surface climatological conditions are used as the initial conditions for the
CGCM, and a land surface model coupled to the AGCM is used for the prediction
of land surface conditions. The climatological distribution of sea ice is used
as the lower boundary condition.
The EPS for
long-range forecasting is run every five days with nine members. Initial
perturbations are estimated for both the atmosphere and the ocean, and
atmospheric initial perturbations are obtained using the Breeding of Growing
Modes (BGM) method. Oceanic initial perturbations are estimated through
MOVE/MRI.COM-G forced with the surface heat and momentum fluxes of the
atmospheric initial perturbation fields.
The EPS with the
CGCM for long-range forecasting, as well as for El Niño prediction, adopts a
combination of the initial perturbation method and the Lagged Average
Forecasting (LAF) method. Nine members are run every five days, and the EPS
consists of 51 members for the latest six initial dates. The 51-member ensemble
is used for the three-month forecast issued every month and for a warm/cold
season forecast issued five times a year (in February, March, April, September
and October). GPV products of the EPS for long-range forecasting are made
available on the TCC website by the 22nd of each month.
Schema
of aggregation for the ensemble members in t the
EPS for long-range forecasting
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updated : Feb.8, 2010 |
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