An overview on progress in Beijing Climate Center Climate System Model—Its development and application to climate change studies

This paper presents an overview on progress in the development of the Beijing Climate Center Climate System Model (BCC_CSM) and its four components: atmosphere, land surface, ocean and sea ice. It focuses on the two recent versions, i.e., BCC_CSM1.1 with a coarse atmospheric resolution (approximately 2.8125°×2.8125°) and BCC_CSM1.1(m) with a medium atmospheric resolution (approximately 1.125°×1.125°). Both versions of BCC_CSM are fully-coupled climate-carbon cycle models involving terrestrial and oceanic carbon cycle and vegetation dynamics. They can well simulate the atmospheric CO2 concentration and its temporal evolution when forced by anthropogenic emissions of CO2. They contribute to the CMIP5 efforts supporting the IPCC AR5. A large amount of simulations from BCC_CSM1.1 and BCC_CSM1.1(m) are available for studies on global climate and future climate projection.This paper also shows a few examples using BCC_CSM. There is an evaluation of BCC_CSM1.1 and BCC_CSM1.1(m) in reproducing present-day climate (especially the spatial pattern and seasonal feature of precipitation and surface air temperature, at global scale and in East Asia), in simulating paleoclimate during the last millennium, and in projecting climate change up to 2100. The results show that both BCC_CSM1.1 and BCC_CSM1.1(m) have good performances compared with the other CMIP5 models. It seems that BCC_CSM1.1(m) with a higher horizontal resolution has a better performance for climate mean state at regional scales than BCC_CSM1.1 does.