A study of biases in simulation of the Indian Ocean basin mode and its capacitor effect in CMIP3/CMIP5 models
A study of biases in simulation of the Indian Ocean basin mode and its capacitor effect in CMIP3/CMIP5 models
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DOI：
10.1007/s00382-015-2579-0
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发表时间：
2016-11
期刊：
影响因子：
4.6
通讯作者：
W. Tao;G. Huang;Kaiming Hu;H. Gong;G. Wen;Lin Liu
中科院分区：
文献类型：
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作者：
W. Tao;G. Huang;Kaiming Hu;H. Gong;G. Wen;Lin Liu
基于15个耦合模式比对计划（CMIP）第3阶段（CMIP 3）和32个CMIP第5阶段（CMIP 5）模式，对印度洋海盆模式（IOBM）模拟偏差及其电容效应进行了详细诊断。云-辐射-SST（CRS）反馈和风-蒸发-SST（WES）反馈是SST变化的两个主要大气过程。大多数CMIP模型模拟较强的CRS反馈和较弱的WES反馈。在厄尔尼诺/南方涛动发展年的北半球秋季和次年春季，海洋大陆上的降水异常和南印度洋上的反气旋异常都有较弱的偏差。大多数CMIP模式模拟合理的短波辐射（SWR）和较弱的潜热通量（LHF）异常。这导致大气过程的弱偏差。冬季降水异常偏西，异常反气旋与观测值相当。因此，大多数模式模拟更强的SWR和合理的LHF异常，导致大气过程的强烈偏差。在大多数模式中，温跃层反馈更强。尽管气候学温跃层存在深偏差，但大多数模式都能捕捉到合理的海平面高度引起的SST异常。因此，在春季，海洋过程的影响抵消了大气过程的弱偏差，热带印度洋变暖持续到夏季。但由于电容效应的弱偏西，使得西北太平洋反气旋异常偏弱。模式中不真实的西太平洋海温异常有利于太平洋Rossby波的向西伸，削弱了印度洋Kelvin波的影响。此外，西太平洋变暖迫使NWP反气旋比观测更北，这表明来自太平洋的主要强迫。与CMIP 3相比，CMIP 5模型更真实地模拟反馈，显示出更少的多样性。因此，CMIP 5模型的整体性能优于CMIP 3模型。
Based on 15 Coupled Model Intercomparison Project (CMIP) phase 3 (CMIP3) and 32 CMIP phase 5 (CMIP5) models, a detailed diagnosis was carried out to understand what compose the biases in simulation of the Indian Ocean basin mode (IOBM) and its capacitor effect. Cloud-radiation-SST (CRS) feedback and wind-evaporation-SST (WES) feedback are the two major atmospheric processes for SST changes. Most CMIP models simulate a stronger CRS feedback and a weaker WES feedback. During boreal fall of the El Niño/Southern Oscillation developing year and the following spring, there are weak biases of suppressed rainfall anomalies over the Maritime Continent and anomalous anticyclone over South Indian Ocean. Most CMIP models simulate reasonable short wave radiation (SWR) and weaker latent heat flux (LHF) anomalies. This leads to a weak bias of atmospheric processes. During winter, however, the rainfall anomalies are stronger due to west bias, and the anomalous anticyclone is comparable to observations. As such, most models simulate stronger SWR and reasonable LHF anomalies, leading to a strong bias of atmospheric processes. The thermocline feedback is stronger in most models. Though there is a deep bias of climatology thermocline, most models capture reasonable sea surface height-induced SST anomalies. Therefore, the effect of oceanic processes offset the weak bias of atmospheric processes in spring, and the tropical Indian Ocean warming persists into summer. However, anomalous northwest Pacific (NWP) anticyclone is weaker due to weak and west bias of the capacitor effect. The unrealistic western Pacific SST anomalies in models favor the westward extension of Rossby wave from the Pacific, weakening the effect of Kelvin wave from the Indian Ocean. Moreover, the western Pacific warming forces the NWP anticyclone move farther north than observations, suggesting a major forcing from the Pacific. Compared to CMIP3, CMIP5 models simulate the feedbacks more realistically and display less diversity. Thus, the overall performance of CMIP5 models is better than that of CMIP3 models.