Handling data includes collecting data, decoding data and data quality control. The observation data used in this system contains both GTSPP data (from 1981) and Argo data (from 1998). The real-time GTSPP data are obtained from the data bank of Meteorological Information Center of CMA (China Meteorological administration). Argo data are downloaded from French Research Institute for Exploitation of the Sea(IFREMER). It should be pointed out that we have used the observation data from NOAA and MEDS to retrieve history observation data.
Having been calculated in the observation points, the wind stress data are processed by means of optimal interpolation. The wind data, we accessed, for years from 1982 to 1990 in the tropic Pacific are a bit lack. we will manage to retrieve these data.
The scheme of 3-dimensional variation is adopted in BCC-GODAS. Meanwhile, a time-window, about 4-weeks, is opened in order to obtain as much observation information as possible. In BCC-GODAS, both sea temperature and salinity observation data, if available, are input. The background errors covariance involves a vertical weak correlation and a loose correlation between temperature and salinity.
The dynamic model used in this system is L30T63 OGCM Version 1.0, which is established and developed by LASG/IAP. This model has the same horizontal resolution as T63 atmosphere model, and there are 30 layers in the vertical direction, in which the first 10 layers are from 0 to 250m, the second 10 layers span from 250m to 1000m, and the last 10 layers are located deeper till 5600m. There are two vertical mixing parameterization schemes in this model. One is based on Richardson number applied in the tropic region from 30S to 30N. Another is Isopycnal mixing scheme. While using this model, we have made some improvement on the vertical mixing parameterization scheme: a transition zone to connect two areas mentioned above is designed, and the criterion of gradient of density in Isopycnal mixing scheme is redefined as a spatial function rather than a constant.
Acknowledgment: we wish to thank IFREMER, CDC/NOAA, NODC/NOAA, MEDS(Canada) and China Argo Realtime Data Center for their observation data.