ENSO representation in climate models: from CMIP3 to CMIP5
ENSO representation in climate models: from CMIP3 to CMIP5
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DOI：
10.1007/s00382-013-1783-z
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发表时间：
2014-04-01
期刊：
影响因子：
4.6
通讯作者：
Vialard, J.
中科院分区：
文献类型：
--
作者：
Bellenger, H.;Guilyardi, E.;Vialard, J.
分析了CMIP 3和CMIP 5耦合模式对热带太平洋平均状态和厄尔尼诺-南方涛动（ENSO）的模拟能力。CMIP 5多模式集合显示了令人鼓舞的30%的减少普遍的冷偏差在西太平洋，但没有量子飞跃ENSO性能相比CMIP 3。因此，CMIP 3和CMIP 5可以被认为是一个大的集合（CMIP 3 + CMIP 5）的多模式ENSO分析。然而，CMIP 3 ENSO振幅的太大差异在CMIP 5中减少了两倍，ENSO生命周期（表面温度异常的位置，季节性相位锁定）略有改善。但是，厄尔尼诺/南方涛动的其他基本特征，如中太平洋降水异常，仍然没有得到充分的说明。在CMIP 5集合中，海表面温度（SST）-潜热通量反馈略有改善，但风-SST反馈仍然被低估了20- 50%，短波-SST反馈仍然被低估了2倍。因此，ENSO振幅的改善可能是误差补偿的结果。CMIP模式的能力，以模拟SST短波反馈，错误的ENSO在CGCM的一个主要来源，进一步详细说明。在观测中，这种反馈是强非线性的，因为在季节和年际变化的影响下，真实的大气从沉降（正反馈）状态切换到对流（负反馈）状态。只有三分之一的CMIP 3 + CMIP 5模型再现了这种状态转变，其他模型仍然锁定在两个状态之一。模拟的短波反馈非线性随ENSO振幅的增加而增加，弹簧中的这种反馈的振幅与模型模拟ENSO锁相的能力密切相关。在最后阶段，提出了一个指标子集，以综合每个CMIP 3和CMIP 5模型模拟ENSO主要特征和关键大气反馈的能力。
We analyse the ability of CMIP3 and CMIP5 coupled ocean-atmosphere general circulation models (CGCMs) to simulate the tropical Pacific mean state and El Nio-Southern Oscillation (ENSO). The CMIP5 multi-model ensemble displays an encouraging 30 % reduction of the pervasive cold bias in the western Pacific, but no quantum leap in ENSO performance compared to CMIP3. CMIP3 and CMIP5 can thus be considered as one large ensemble (CMIP3 + CMIP5) for multi-model ENSO analysis. The too large diversity in CMIP3 ENSO amplitude is however reduced by a factor of two in CMIP5 and the ENSO life cycle (location of surface temperature anomalies, seasonal phase locking) is modestly improved. Other fundamental ENSO characteristics such as central Pacific precipitation anomalies however remain poorly represented. The sea surface temperature (SST)-latent heat flux feedback is slightly improved in the CMIP5 ensemble but the wind-SST feedback is still underestimated by 20-50 % and the shortwave-SST feedbacks remain underestimated by a factor of two. The improvement in ENSO amplitudes might therefore result from error compensations. The ability of CMIP models to simulate the SST-shortwave feedback, a major source of erroneous ENSO in CGCMs, is further detailed. In observations, this feedback is strongly nonlinear because the real atmosphere switches from subsident (positive feedback) to convective (negative feedback) regimes under the effect of seasonal and interannual variations. Only one-third of CMIP3 + CMIP5 models reproduce this regime shift, with the other models remaining locked in one of the two regimes. The modelled shortwave feedback nonlinearity increases with ENSO amplitude and the amplitude of this feedback in the spring strongly relates with the models ability to simulate ENSO phase locking. In a final stage, a subset of metrics is proposed in order to synthesize the ability of each CMIP3 and CMIP5 models to simulate ENSO main characteristics and key atmospheric feedbacks.