The Beijing Climate Center atmospheric general circulation model: description and its performance for the present-day climate

Abstract

The Beijing Climate Center atmospheric general circulation model version 2.0.1 (BCC_AGCM2.0.1) is described and its performance in simulating the present-day climate is assessed. BCC_AGCM2.0.1 originates from the community atmospheric model version 3 (CAM3) developed by the National Center for Atmospheric Research (NCAR). The dynamics in BCC_AGCM2.0.1 is, however, substantially different from the Eulerian spectral formulation of the dynamical equations in CAM3, and several new physical parameterizations have replaced the corresponding original ones. The major modification of the model physics in BCC_AGCM2.0.1 includes a new convection scheme, a dry adiabatic adjustment scheme in which potential temperature is conserved, a modified scheme to calculate the sensible heat and moisture fluxes over the open ocean which takes into account the effect of ocean waves on the latent and sensible heat fluxes, and an empirical equation to compute the snow cover fraction. Specially, the new convection scheme in BCC_AGCM2.0.1, which is generated from the Zhang and McFarlane's scheme but modified, is tested to have significant improvement in tropical maximum but also the subtropical minimum precipitation, and the modified scheme for turbulent fluxes are validated using EPIC2001 in situ observations and show a large improvement than its original scheme in CAM3. BCC_AGCM2.0.1 is forced by observed monthly varying sea surface temperatures and sea ice concentrations during 1949-2000. The model climatology is compiled for the period 1971-2000 and compared with the ERA-40 reanalysis products. The model performance is evaluated in terms of energy budgets, precipitation, sea level pressure, air temperature, geopotential height, and atmospheric circulation, as well as their seasonal variations. Results show that BCC_AGCM2.0.1 reproduces fairly well the present-day climate. The combined effect of the new dynamical core and the updated physical parameterizations in BCC_AGCM2.0.1 leads to an overall improvement, compared to the original CAM3.

An evaluation of boreal summer intra-seasonal oscillation simulated by BCC_AGCM2.2

“…The model provides overall improvements to climate simulations in comparison to CAM3, especially for simulating the tropical maxima/subtropical minima of precipitation, wind stress, and sensible and latent heat fluxes at the ocean surface Kan et al 2015). A detailed description of BCC_AGCM can be found in Wu et al (2010) and Wu (2012).…”

Application and evaluation of a new radiation code under McICA scheme in BCC_AGCM2.0.1

“…5, we conclude with a brief summary. (Wu et al, 2010). The model runs at T42 spectral resolution (approximately 2.8 • × 2.8 • ) horizontally, and it uses vertical hybrid δ-pressure coordinates including 26 layers with the top located at about 2.9 hPa.…”

“…These include new reference atmosphere and surface pressures; a revised convection scheme (Zhang and Mu, 2005) that significantly improves the tropical rainfall simulation; a different function for calculating the snow-cover fraction that influences the resulting surface albedo, especially in polar and plateau regions (Wu and Wu, 2004); a new adiabatic adjustment originated by Yan (1987); and new methods for calculating turbulent fluxes over ocean surface that remove the systematic biases in the wind stress and sensible and latent heat fluxes in CAM3. A more detailed description of BCC_AGCM2.0.1 can be found in Wu et al (2010). In the present research, the interactive Canadian Aerosol Module (CAM) (Gong et al, 2003) with updated aerosol emission sources (Zhou et al, 2012) is used to predict atmospheric aerosol burdens .…”

Effects of climate change on heating and cooling degree days and potential energy demand in the household sector of China

“…The model simulations are conducted with the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model v.4, RegCM4 , driven by the global model BCC_CSM1.1 (Beijing Climate Center Climate System Model v.1.1; Wu et al 2010, Xin et al 2013. The RegCM4 domain covers continental China and surrounding areas with a grid spacing of 50 km, and the simulation covers the period 1951−2005 for the present day (with observed GHG concentrations) and 2006−2099 for the future under the mid-level RCP4.5 and high-level RCP8.5 scenarios, respectively (Moss et al 2010).…”