Application and evaluation of McICA scheme in BCC-AGCM2.0.1

Abstract

McICA, a new cloud-radiation scheme that can easily define the sub-grid cloud structures, is incorporated into the National Climate Center's Global Climate Model, called BCC-AGCM2.0.1. As random noises is inevitably introduced by the scheme, it's important to evaluate and estimate how the noises behave and whether the modeled climate will be degraded by the noises. Results here showed a minor perturbation of modeled climate within McICA samples, and the modeled climate fields are impacted very little by McICA noises, with global mean biases at the order of 0.01% compared to the reference ICA results. Good agreement between McICA and ICA results is also illustrated from zonal mean, vertical, and domain distributions of variables. So, it's highly reliable to use the McICA cloud-radiation scheme in BCC-AGCM2.0.1 to do climate researches. Because random noises have little impact on the modeling, the modeling ability of BCC-AGCM2.0.1 still depends on its physical parameterization and dynamic framework improvements. Considering that cloud and radiation processes are separately coded in the new scheme, it's now very easy to make improvement and progress in both cloud and radiation codes, which facilitates and allows more space for the further development of the model. © 2013 AIP Publishing LLC.