Sub Group for the Development of a High-Resolution Coupled Ocean-Atmosphere Climate Model

The climate change caused by the increased atmospheric concentration of greenhouse gases and aerosols due to human activity is one of the major concerns of the world. For the assessment of the climate change, climate models have been utilized to project the future climate based on scenarios of future socio-economic development of the world. A coarse spatial resolution of climate models has been one of the sources of uncertainty in such projections. This project aims at reducing the uncertainty of the future climate change projection, using a high-resolution coupled ocean atmosphere climate model running on the fastest super-computer in the world, the Earth Simulator.

The horizontal resolution is about 1º for the atmospheric part and about 1/4º x 1/6º for the oceanic part. With this resolution, precipitation systems such as baiu front and tropical cyclones can be represented and the change in future floods can be discussed more realistically than before. The oceanic part not only permits meso-scale eddies, but also realistically represents complex current system around the sinking region in the northern North Atlantic, which plays an important role in the climate change. The results will contribute with some novel findings on climate change to the IPCC Fourth Assessment Report, which is going to be published in 2007.

This research is conducted as a joint project with the Center for Climate System Research of the University of Tokyo (CCSR) and the National Institute for Environmental Studies (NIES).