ABSTRACT

With a westerly wind burst (WWB) parameterization scheme introduced into a hybrid coupled model (HCM), we investigated in Part 1 of this study the impact of WWBs on El Nino – Southern Oscillation (ENSO) simulation features, including asymmetry, phase locking, and diversity. In the second part, we investigate the impact of WWBs on ENSO prediction skills. To achieve this, two ensemble experiments, one with WWBs and one without WWBs, are performed to evaluate the predictions of sea surface temperature (SST) anomalies.

The results show that both experiments can predict the SST anomalies in the equatorial central and eastern Pacific up to lead times of 12 months. The correlation coefficient between the model and observations shows that the WWB experiment produces better prediction skills than the experiment without WWBs, especially at lead times longer than four months during El Niño events. This result is consistent with the expectation that the WWB parameterization scheme plays an important role in describing physical processes, which is indicated in Part 1. We also presented a predictability analysis for Central Pacific (CP) and Eastern Pacific (EP) El Niño events. The prediction of both types of El Niño events is also improved by the WWB parameterization scheme at long lead times.

摘要

通过将西风爆发 (WWB) 参数化方案引入混合耦合模型 (HCM)，我们在本研究的第 1 部分中研究了 WWB 对厄尔尼诺 - 南方涛动 (ENSO) 模拟特征的影响，包括不对称性、锁相、和多样性。在第二部分中，我们研究了 WWB 对 ENSO 预测技能的影响。为了实现这一目标，进行了两项集合实验，一项有 WWB，另一项没有 WWB，以评估海面温度 (SST) 异常的预测。

结果表明，两项实验均可提前12个月预测赤道中、东太平洋海温异常。模型与观测值之间的相关系数表明，WWB 实验比没有 WWB 的实验产生更好的预测能力，特别是在厄尔尼诺事件期间的提前期超过四个月的情况下。这一结果与第 1 部分中指出的 WWB 参数化方案在描述物理过程中发挥重要作用的预期一致。我们还提出了中太平洋 (CP) 和东太平洋 (EP) 厄尔尼诺事件的可预测性分析。WWB 参数化方案在较长的交付时间内也改进了对两种类型厄尔尼诺事件的预测。