The assimilated observational data for ocean in the experiment are monthly
mean temperature and salinity field derived from the World Ocean Database
2001 (WOD2001), 10daily averaged Reynolds SST field and the
TOPEX/Poseidon 10daily mean sea surface height anomaly. The continuous
fields yielded as “Kyousei K7”ocean data assimilation product are also used as
quasiobservation to fill the gaps of very sparse observation. The atmospheric
data are the PREP BUFR dataset taken from the National Centers for Environmental
Prediction (NCEP) for air temperature, specific humidity and wind
vector after some processing to obtain 10daily mean and to perform appropriate
quality checks. 10daily mean 10m scalar wind from SSM/I observation are multipled
by ECMWF wind direction data to obtain wind vector quasiobservation
over the ocean.
The optimization problem to minimize the cost is solved by the iteration with
conjugate gradient method using the gradient calculated by the atmosphereocean
coupled adjoint code.
6 Ensemble
Because weather mode in the shorter period than 10days is not controlled
in the optimization with the observational data, we performed coupled model
integrations under 11 different atmospheric initial conditions using optimized
ocean initial condition and adjustment factor. The ensemble of atmospheric
initial conditions are taken, at 1day intervals, from the first 5 days of the first
month of the assimilation window and from the last 5 day of the month perior to
the first month of the assimilation window. An ensemble member which seems
to express the reality the best is selected for each window, and they are pieced
together as a continuous data for three years .
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