Predictability and prediction of persistent cool states of the Tropical Pacific Ocean
Predictability and prediction of persistent cool states of the Tropical Pacific Ocean
复制标题
热带太平洋持续凉爽状态的可预测性和预报
DOI：
10.1007/s00382-016-3446-3
复制
发表时间：
2017
期刊：
影响因子：
4.6
通讯作者：
Dong Eun Lee
中科院分区：
文献类型：
--
作者：
N. Ramesh;M. Cane;R. Seager;Dong Eun Lee
热带太平洋表现出持续冷却的海表面温度(SST)异常，持续几年到十年，要么没有厄尔尼诺事件，要么有少量弱厄尔尼诺事件。它们在温带地区造成了大规模干旱，包括20世纪30年代的沙尘暴等北美主要干旱，还调节了全球平均地表温度。在这里，我们展示了两个不同复杂程度的模型--Zebiak-Cane中间模型和地球物理流体动力学实验室耦合模型2.1版--能够以现实的方式产生这样的周期。然后，我们在Zebiak-Cane模型中使用一系列带有扰动初始态的实验来测试这些周期的可预测性。我们的结果表明，在大多数情况下，冷平均状态是可预测的。然后，我们应用该方法对年代际平均状态的变化进行了追溯预测，并对未来十年热带太平洋的平均状态进行了预测。我们的研究结果表明，在2015-2016年厄尔尼诺现象之后，太平洋将经历一次变暖的平均状态。这可能意味着自1997-1998年厄尔尼诺现象以来北美西南部普遍遭受的比正常情况更干燥的天气的停止，以及21世纪全球变暖的暂停。讨论了对我们理解这种持续凉爽状态的起源的意义，以及改进大规模干旱预测的可能性。
The Tropical Pacific Ocean displays persistently cool sea surface temperature (SST) anomalies that last several years to a decade, with either no El Niño events or a few weak El Niño events. These cause large-scale droughts in the extratropics, including major North American droughts such as the 1930s Dust Bowl, and also modulate the global mean surface temperature. Here we show that two models with different levels of complexity—the Zebiak–Cane intermediate model and the Geophysical Fluid Dynamics Laboratory Coupled Model version 2.1—are able to produce such periods in a realistic manner. We then test the predictability of these periods in the Zebiak–Cane model using an ensemble of experiments with perturbed initial states. Our results show that in most cases the cool mean state is predictable. We then apply this method to make retrospective forecasts of shifts in the decadal mean state and to forecast the mean state of the Tropical Pacific Ocean for the upcoming decade. Our results suggest that the Pacific will undergo a shift to a warmer mean state after the 2015–2016 El Niño. This could imply the cessation of the drier than normal conditions that have generally afflicted southwest North America since the 1997–1998 El Niño, as well as the twenty-first-century pause in global warming. Implications for our understanding of the origins of such persistent cool states and the possibility of improving predictions of large-scale droughts are discussed.