Assessment of the Ability of CMIP6 GCMS to Simulate the Boreal Summer Intraseasonal Oscillation Over Southeast Asia
Assessment of the Ability of CMIP6 GCMS to Simulate the Boreal Summer Intraseasonal Oscillation Over Southeast Asia
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DOI：
10.3389/fclim.2021.716129
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
A. A. Abatan-A.;M. Collins;M. Babel;Dibesh Khadka;Yenushi K. De Silva
中科院分区：
文献类型：
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作者：
A. A. Abatan-A.;M. Collins;M. Babel;Dibesh Khadka;Yenushi K. De Silva
北半球夏季季节内振荡（BSISO）在亚洲夏季风系统调制的大范围天气和气候现象的季节内变率中起着重要作用。本研究评估了19个耦合模式相互比较项目第6阶段（CMIP 6）模式的优点和缺点，以重现BSISO的基本特征。模式的降雨和大尺度气候进行了评估GPCP和ERA 5再分析数据集。所有模式都表现出30-60天带通过滤的降水和对流异常的季节内变化，但与观测相比，具有不同的幅度。CMIP 6模型捕捉到了波数1和2处的向东/向北传播的BSISO结构，但与对流信号的强度和位置有关。然而，该模型显示出良好的能力，以模拟的功率谱和相干平方的组合经验正交函数（CEOF）的主成分，并可以捕捉CEOF模式和红噪声之间的区别。另外，一些CMIP 6模式也能捕捉到BSISO季节内相干传播的特征，如Hovmöller图所示。所选模式还模拟了湿静力能对东南亚地区季内降水和湿静力能之间关系的贡献，尽管信号很弱。综合来看，CMIP 6模式中的部分模式能够较好地模拟研究区夏季气候和季节内变化，也能较好地模拟BSISO的传播特征，但仍存在偏差。
The boreal summer intraseasonal oscillation (BSISO) plays an important role in the intraseasonal variability of a wide range of weather and climate phenomena across the region modulated by the Asian summer monsoon system. This study evaluates the strengths and weaknesses of 19 Coupled Model Intercomparison Project Phase 6 (CMIP6) models to reproduce the basic characteristics of BSISO. The models' rainfall and largescale climates are evaluated against GPCP and ERA5 reanalysis datasets. All models exhibit intraseasonal variance of 30–60-day bandpass-filtered rainfall and convection anomalies but with diverse magnitude when compared with observations. The CMIP6 models capture the structure of the eastward/northward propagating BSISO at wavenumbers 1 and 2 but struggle with the intensity and location of the convection signal. Nevertheless, the models show a good ability to simulate the power spectrum and coherence squared of the principal components of the combined empirical orthogonal function (CEOF) and can capture the distinction between the CEOF modes and red noise. Also, the result shows that some CMIP6 models can capture the coherent intraseasonal propagating features of the BSISO as indicated by the Hovmöller diagram. The contribution of latent static energy to the relationship between the moist static energy and intraseasonal rainfall over Southeast Asia is also simulated by the selected models, albeit the signals are weak. Taking together, some of the CMIP6 models can represent the summertime climate and intraseasonal variability over the study region, and can also simulate the propagating features of BSISO, but biases still exist.