Study on sensitivity of CCAM model to the sea surface temperature boundary conditions

Abstract

The ability of simulation on large-scale global circulation, as well as temperature and rainfall over Vietnam area with different sea surface temperature (SST) boundary conditions by the Conformal-Cubic Atmospheric Model (CCAM) is presented in this paper. CCAM is a global circulation model, which may be used in the variable resolution mode to function as a regional climate model. That is, the model may be integrated with high horizontal resolution over the area of interest, with the resolution gradually decreasing as one moved away from the area of interest. The results show that model has well predicted large global circulation all over the global compared to Climate Forecast System (CFS) analysis data, two experiment of CCAM model were not too different with CFS model. For detailed forecasts in Vietnam region, the CCAM model will capture surface temperature compared to observed data with correlation coefficient above 0.85. Forecast temperature of CCAM tends to be lower than observed data, but the magnitude of error is not so much. Comparing the two experiments, forecast skill of CCAM_IRI is slightly better than CCAM_CFS. For rainfall, CCAM generally tends to forecast rainfall higher than observation data in summer and lower in winter. The predictive skill of rainfall in short lead times is better than others and skill of CCAM_CFS is significantly better than CCAM_IRI.

Keywords

• CCAM
• forecast SST
• global model
• region Vietnam
• seasonal forecasting