Assessing the climate-scale variability of atmospheric rivers affecting western North America
Assessing the climate-scale variability of atmospheric rivers affecting western North America
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DOI：
10.1002/2017gl074175
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发表时间：
2017-08-16
影响因子：
5.2
通讯作者：
Rutz, Jonathan J.
中科院分区：
文献类型：
--
作者：
Gershunov, Alexander;Shulgina, Tamara;Rutz, Jonathan J.
一种新的方法自动检测大气河流（ARs）的开发和应用到大气再分析，产生了广泛的目录ARs降落沿沿着北美西海岸在1948-2017年。该目录提供了大量的变量，可用于详细检查AR案例及其气候尺度变化。AR活动的新记录，提出，验证和检查这里，提供了一个视角的季节性周期和年际-年代际变化的AR活动影响北美西部的水文气候。重要的是，AR强度并不完全遵循AR频率的气候模式。使用高分辨率降水数据集证明了与水文气候的密切联系。我们描述了AR活动的季节性进展，并诊断与太平洋海面温度中表达的气候变率的联系，揭示了与太平洋年代际变率，最近的区域异常以及陆地下降AR活动的普遍上升趋势的联系。后一种趋势与从变暖的北太平洋到北美大陆的蒸汽输送的长期增加是一致的。新的目录提供了前所未有的机会，研究气候尺度的行为和影响北美西部的AR的可预测性。简单的语言摘要我们已经创建了一个新的七十年的大气河流行为的目录降落在北美西海岸。该目录已验证独立的降水观测，以确保其中所代表的大气河流与极端地形降水。我们的研究结果清楚地描绘了大气河流在加州的水文气候的突出作用。在最近的加州干旱及其最近的失误中，大气河流的变化特别重要。我们还检测到一个长期增加的趋势，在水蒸气输送冲击与大气河流和整体冬季水蒸气输送与气候变暖相关的北美西海岸。此外，我们的研究结果表明，潜在的可预测性的季节性行为的大气河流可能取决于气候变率的来源有点不同的总水汽输送。
A new method for automatic detection of atmospheric rivers (ARs) is developed and applied to an atmospheric reanalysis, yielding an extensive catalog of ARs land-falling along the west coast of North America during 1948-2017. This catalog provides a large array of variables that can be used to examine AR cases and their climate-scale variability in exceptional detail. The new record of AR activity, as presented, validated and examined here, provides a perspective on the seasonal cycle and the interannual-interdecadal variability of AR activity affecting the hydroclimate of western North America. Importantly, AR intensity does not exactly follow the climatological pattern of AR frequency. Strong links to hydroclimate are demonstrated using a high-resolution precipitation data set. We describe the seasonal progression of AR activity and diagnose linkages with climate variability expressed in Pacific sea surface temperatures, revealing links to Pacific decadal variability, recent regional anomalies, as well as a generally rising trend in land-falling AR activity. The latter trend is consistent with a long-term increase in vapor transport from the warming North Pacific onto the North American continent. The new catalog provides unprecedented opportunities to study the climate-scale behavior and predictability of ARs affecting western North America.Plain Language Summary We have created a new seven-decade-long catalog of atmospheric river behavior land-falling upon the west coast of North America. The catalog has been validated against independent precipitation observations to ensure that the atmospheric rivers represented therein are associated with extreme orographic precipitation. Our results clearly delineate a prominent role for atmospheric rivers in California's hydroclimate. Atmospheric river variability has been particularly important in the recent California drought as well as its most recent lapse. We also detect a long-term increasing trend in water vapor transport impinging on the west coast of North America associated with atmospheric rivers and overall wintertime water vapor transport associated with climate warming. Our results, moreover, suggest that potential predictability of seasonal behavior of atmospheric rivers may hinge on sources of climatic variability somewhat different from that of total water vapor transport.