Simple stochastic dynamical models capturing the statistical diversity of El Niño Southern Oscillation
Simple stochastic dynamical models capturing the statistical diversity of El Niño Southern Oscillation
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DOI：
10.1073/pnas.1620766114
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
N. Chen;A. Majda
中科院分区：
文献类型：
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作者：
N. Chen;A. Majda
厄尔尼诺南方涛动（ENSO）对全球气候和季节预测有重要影响。一个简单的建模框架，自动捕捉统计多样性的ENSO。除了模拟具有真实特征的不同类型的厄尔尼诺和拉尼娜现象外，该模型还成功地捕捉了太平洋不同厄尔尼诺区域的方差和非高斯统计特性。特别是，在20世纪90年代观察到的情节，其中5年的中央太平洋厄尔尼诺，其次是超级厄尔尼诺，然后拉尼娜，是由模式再现。该模型的主要特点是状态依赖的随机风突发和非线性平流的海面温度，允许不同的ENSO状态之间的有效转换。厄尔尼诺南方涛动（ENSO）对全球气候和季节预报有重要影响。一个简单的建模框架，自动捕捉统计多样性的ENSO。首先，包括西风和东风的风突发的随机参数化耦合到一个简单的海洋-大气模型，否则是确定性的，线性的，稳定的。第二，一个简单的非线性纬向平流没有特设的背景海表面温度（SST）梯度和平均东风信风异常表示的几十年的贸易风加速参数化都纳入耦合模式，使异常温暖的SST在太平洋中部。然后，一个三态随机马尔可夫跳过程被用来驱动的风突发活动，这取决于西太平洋暖池的强度在一个简单而有效的方式。它使耦合模式能够模拟准规则的中度传统厄尔尼诺、超级厄尔尼诺和中太平洋厄尔尼诺以及具有真实特征的拉尼娜。除了SST的异常外，ENSO各位相的步行者环流异常都与自然界相似。特别是，耦合模式成功地再现了在1990年代观察到的事件，其中一系列的5年CP厄尔尼诺现象之后是超级厄尔尼诺现象，然后是拉尼娜现象。重要的是，从西太平洋到东太平洋的不同厄尔尼诺区域的方差和非高斯统计特征都被耦合模式捕获。
Significance The El Niño Southern Oscillation (ENSO) has significant impact on global climate and seasonal prediction. A simple modeling framework is developed here that automatically captures the statistical diversity of ENSO. In addition to simulating different types of El Niño and La Niña with realistic features, the model succeeds in capturing both the variance and the non-Gaussian statistical properties in different Niño regions spanning the Pacific. Particularly, the observed episode during the 1990s, where a 5-y central Pacific El Niño is followed by a super El Niño and then a La Niña, is reproduced by the model. Key features of the model are state-dependent stochastic wind bursts and nonlinear advection of sea-surface temperature that allow effective transitions between different ENSO states. The El Niño Southern Oscillation (ENSO) has significant impact on global climate and seasonal prediction. A simple modeling framework is developed here that automatically captures the statistical diversity of ENSO. First, a stochastic parameterization of the wind bursts including both westerly and easterly winds is coupled to a simple ocean–atmosphere model that is otherwise deterministic, linear, and stable. Second, a simple nonlinear zonal advection with no ad hoc parameterization of the background sea-surface temperature (SST) gradient and a mean easterly trade wind anomaly representing the multidecadal acceleration of the trade wind are both incorporated into the coupled model that enables anomalous warm SST in the central Pacific. Then a three-state stochastic Markov jump process is used to drive the wind burst activity that depends on the strength of the western Pacific warm pool in a simple and effective fashion. It allows the coupled model to simulate the quasi-regular moderate traditional El Niño, the super El Niño, and the central Pacific (CP) El Niño as well as the La Niña with realistic features. In addition to the anomalous SST, the Walker circulation anomalies at different ENSO phases all resemble those in nature. In particular, the coupled model succeeds in reproducing the observed episode during the 1990s, where a series of 5-y CP El Niños is followed by a super El Niño and then a La Niña. Importantly, both the variance and the non-Gaussian statistical features in different Niño regions spanning from the western to the eastern Pacific are captured by the coupled model.