IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA 52242
IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA 52242.
Proc Natl Acad Sci U S A. 2018 Jan 30;115(5):891-896. doi: 10.1073/pnas.1717883115. Epub 2018 Jan 16.
Atmospheric rivers (ARs) exert major socioeconomic repercussions along the US West Coast by inducing heavy rainfall, flooding, strong winds, and storm surge. Despite the significant societal and economic repercussions of these storms, our understanding of the physical drivers responsible for their interannual variability is limited, with different climate modes identified as possible mechanisms. Here we show that the Pacific-Japan (PJ) teleconnections/patterns and the East Asian subtropical jet (EASJ) exhibit a strong linkage with the total frequency of ARs making landfall over the western United States, much stronger than the other potential climate modes previously considered. While our findings indicate that the PJ pattern and EASJ are the most relevant climate modes driving the overall AR activity, we also uncover heterogeneities in AR tracks. Specifically, we show that not all ARs making landfall along the West Coast come from a single population, but rather that it is possible to stratify these storms into three clusters. While the PJ pattern and EASJ are major drivers of AR activity for two clusters, the cluster that primarily affects the US Southwest is largely driven by other climate modes [El Niño Southern Oscillation (ENSO), the Atlantic meridional mode (AMM), the Pacific-North America (PNA) teleconnection pattern, and the North Pacific Gyre Oscillation (NPGO)]. Therefore, important regional differences exist and this information can substantially enhance our ability to predict and prepare for these storms and their impacts.
大气河流（AR）通过引发强降雨、洪水、强风和风暴潮，对美国西海岸产生重大的社会经济影响。尽管这些风暴对社会和经济产生了重大影响，但我们对导致其年际变化的物理驱动因素的理解有限，不同的气候模式被确定为可能的机制。在这里，我们表明，太平洋-日本（PJ）遥相关/模式和东亚副热带急流（EASJ）与美国西部登陆的大气河流总频率之间存在很强的联系，这比以前考虑的其他潜在气候模式要强得多。虽然我们的研究结果表明，PJ 模式和 EASJ 是驱动大气河流活动的最相关气候模式，但我们也发现了大气河流轨迹的异质性。具体来说，我们表明，并非所有登陆西海岸的大气河流都来自单一群体，而是可以将这些风暴分为三个集群。虽然 PJ 模式和 EASJ 是两个集群大气河流活动的主要驱动因素，但主要影响美国西南部的集群在很大程度上是由其他气候模式驱动的[厄尔尼诺南方涛动（ENSO）、大西洋经向模态（AMM）、太平洋-北美（PNA）遥相关模式和北太平洋环流振荡（NPGO）]。因此，存在重要的区域差异，这些信息可以大大提高我们预测和准备这些风暴及其影响的能力。
