BCC_CSM1.1气候模式年代际试验对北极涛动季节回报能力的初步评估

本文基于国家气候中心气候系统模式BCC_CSM1.1自1960—2004年每年起报的年代际预测试验结果,初步评估了该模式对北极涛动（AO）的预报技巧。同时,把该模式年代际预测结果与历史试验模拟比较,分析了气候模式初始化对年代际试验预测季节尺度AO及其年际变化的贡献。结果表明,年代际试验和历史试验均能反映出AO模态是北半球中高纬大气变率第一模态的特征,其中年代际预测试验回报的AO模态与观测的空间相关系数高于历史试验。两组试验基本能再现AO指数冬季最强、夏季最弱的特征。与历史试验相比,年代际预测试验回报月和冬季AO指数与观测的相关系数更高,特别是年代际试验与观测的月AO指数相关系数达到了0.1的显著性水平。年代际试验回报月、春季AO指数的变化周期更接近观测结果。因此,年代际试验中初始状态使用海温资料进行初始化,在一定程度上可以提高AO的回报能力。

Preliminary assessment on the seasonal hindcast skill of the Arctic Oscillation with decadal experiment by BCC_CSM1.1 climate model

This study assesses projection skill of Arctic Oscillation (AO) in initialized decadal experiment with the Beijing Climate Center Climate System Model (BCC_CSM1.1). As compared with the observations and uninitialized historical experiment, the contribution of climate model initialization to predict the seasonal scale AO and its interannual variations is estimated. Results show that the spatial correlation coefficient of AO mode, which depicts the dominant mode of the extra-tropical atmospheric variability, simulated by the decadal experiment is higher than that in the historical experiment. The two groups of experiments can basically reproduce the characteristics of the strongest winter AO index and the weakest summer index. Compared with historical experiment, the correlation coefficient of the monthly and winter AO index is higher in the decadal experiment. In particular, the correlation coefficient of the monthly AO index between the decadal simulations and the observation reached 0.1 significant level. Furthermore, the periodicity of the monthly and spring AO index are achieved only in the decadal experiment. Hence, the hindcast skill of AO is robust when the initial state is initialized by sea surface temperature data.