An ENSO stability analysis. Part II: results from the twentieth and twenty-first century simulations of the CMIP3 models
An ENSO stability analysis. Part II: results from the twentieth and twenty-first century simulations of the CMIP3 models
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DOI：
10.1007/s00382-010-0872-5
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发表时间：
2011-04
期刊：
影响因子：
4.6
通讯作者：
Seon Tae Kim;F. Jin
中科院分区：
文献类型：
--
作者：
Seon Tae Kim;F. Jin
本文采用Jin等人（2006）提出的Bjerknes稳定性指数（BJ），在现有的耦合模式中对厄尔尼诺和南方涛动（ENSO）的总体稳定性进行了评估。对政府间气候变化专门委员会第四次评估报告中使用的耦合模式比较项目第三阶段中的12个耦合模式进行的20世纪和21世纪世纪模拟表明，用BJ指数衡量的ENSO振幅与ENSO稳定性之间存在显著的正相关关系。模拟结果还显示了耦合模式之间ENSO稳定性行为的多样性，这可以归因于不同的平均状态和敏感性的海洋和大气响应风和SST强迫模式。当从耦合模式获得的BJ指数的各个组件与观测相比，它显示，大多数耦合模式低估了热力阻尼效应和纬向平流和温跃层反馈的积极作用。在CO2增加引起的温暖气候下，相对于20世纪世纪的模拟，由BJ指数测量的ENSO稳定性的阻尼和反馈项的变化可以与平均状态变化和相关的大气和海洋响应敏感性变化联系起来。在温室气体增加的情况下，阻尼项和正的纬向平流反馈、温跃层反馈和Ekman反馈项有明显的多模式趋势。然而，在BJ指数公式的正反馈和负阻尼项之间的竞争耦合模式之间的各种行为，防止形成一个明确的结论，未来的预测ENSO稳定性使用当前的耦合模式。
In this study, a Bjerknes stability (BJ) index, proposed by Jin et al. (2006), is adopted to assess the overall stability of El Niño and Southern Oscillation (ENSO) in state-of-the-art coupled models. The twentieth and twenty-first century simulations of 12 coupled models among the coupled model intercomparison project phase 3 models used in the intergovernmental panel on climate change forth assessment report demonstrate a significant positive correlation between ENSO amplitude and ENSO stability as measured by the BJ index. The simulations also show a diversity of behavior regarding the ENSO stability among the coupled models, which can be attributed to different mean state and sensitivity of an oceanic and atmospheric response to wind and SST forcing from model to model. When respective components of the BJ index obtained from the coupled models are compared with those from observations, it is revealed that most coupled models underestimate the thermodynamic damping effect and the positive effect of the zonal advective and thermocline feedback. Under increased CO2induced warm climate, changes, relative to the twentieth century simulations, in the damping and feedback terms responsible for the ENSO stability measured by the BJ index can be linked to mean state changes and associated atmospheric and oceanic response sensitivity changes. There is a clear multi-model trend in the damping terms and positive zonal advective feedback, thermocline feedback, and Ekman feedback terms under enhanced greenhouse gas conditions. However, the various behavior among the coupled models in competition between the positive feedback and negative damping terms in the BJ index formula prevent the formation of a definitive conclusion regarding future projections of ENSO stability using the current coupled models.