Through the key project of short-term climate prediction in the national "Ninth Five-Year Plan" and its enhancement project, a global ocean-atmosphere coupled model with mediate resolution has been established in Beijing Climate Center, which is named as BCC_CM1.0.
The global ocean-atmosphere coupled model is established in open oceanic surface based on global atmospheric circulation model T63L30 AGCM_1.0 and global ocean circulation model L30T63 OGCM_1.0 through Daily Flux Anomaly coupling scheme exchange. It includes a simple land process and a thermodynamic ice model.
A 200-year (1900-2100) control integration experiment of the global ocean-land-atmosphere coupled model indicates that the global coupled model could well reflect mean climatological state. At present, the model is being applied to the short-term climate prediction and modeling research on long-range climate change in the National Climate Center, harvesting several research outcomes.
In the BCC_CM1.0, the T63L16 AGCM_1.0 is coupled with the T63L30 OGCM_1.0 through the coupling scheme of Daily Flux Anomaly (DFA). Ocean and atmosphere exchange momentum, heat, and fresh water through their interface.
The time step length of DFA coupling scheme is 1 day. The integrations of atmospheric model and oceanic model are nearly synchronous. In the global coupled model, the atmospheric model is integrated one day in advance, transmitting the daily averaged surface heat and momentum anomaly to the oceanic model, and then the oceanic model is integrated for one day, transmitting the daily average sea surface temperature (SST) anomaly to the atmospheric model. The coupling process is circulated in such a way. The fresh water flux exchanges between oceanic model and atmospheric model is neglected in the coupled model (Yu et al, 2000).
Since 2002, climate change research has been conducted by using BCC CM1.0. which further deepen our understanding of the climate change and climate variability in China and the world as a whole. Major research efforts include：
² Accomplishing the control experimental integration for 200 years (1900-2100), which satisfactorily reflects the climate status;
² Successfully carrying out climate integration for 150 years and calculating the current climate status and the climate scenarios based on the emission scenarios of three kinds of greenhouse gases emission scenarios and aerosols defined by IPCC, studying the model results of the scenarios of climate change in the world and China for the past and future centuries. Part of the research results was quoted by IPCC Third Assessment Report and appreciated by the experts in the world.
² Participating in the modelling experiment of sulphate aerosol and having accomplished the integration for 130 years;
² Supplying the initial boundary conditions to Regional Climate Model by the CGCM, improving the radiation scheme in the Regional Climate Model, and carrying out integral experiment of the climate change as result of anthropogenic factors during a 30-year period;
² Studing the impact of greenhouse effects and vegetation change on the regional climate change in China by nesting the regional model into global model;
² Taking part into the Atmospheric Model Inter-comparison Project (AMIPⅡ) and having accomplished the control experiment with the forces of observed sea ice and sea surface temperatures in 17 years (1979-1996). Results indicates that this model is highly capable of describing major atmospheric circulation systems influencing China’s climate and this sets a basis for climate research using BCC_CM1.0.
² Participate in IPCC AR4. (bcc.cma.gov.cn/Website/index.php)
[Operational forecast performance]
The operational dynamical modeling system is composed of BCC_CM1.0, BCC_RegCM, and the Monthly Dynamical Extended-Range Forecasting System. BCC_CM1.0 is used to produce seasonal prediction for global and East Asian regions. Regional Climate Model (BCC_RegCM) is nested into BCC_CM1.0 and presents higher resolution climate forecast outcome in China. The Monthly Dynamical Extended-Range Forecasting System is developed based on BCC_AGCM1.0 to produce monthly scales forecast. These three models along with the pre-processing data assimilation system and the post-processing sub-system constitute the first-generation of operational system of dynamic climate prediction models in China and provide useful tools for climate change research. It has been used to produce short-term climate prediction on seasonal, monthly and inter-annual scales for the first time in China. Generally speaking, it has good performance in the historical hindcasts from 1983 to 2001 and trial operational forecasts from 2002 to 2005.
(Seasonal Prediction by BCC-CM1.0: bcc.cma.gov.cn/Website/index.php)