Freezing Rain Events Related to Atmospheric Rivers and Associated Mechanisms for Western North America
Freezing Rain Events Related to Atmospheric Rivers and Associated Mechanisms for Western North America
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DOI：
10.1029/2019gl084647
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发表时间：
2019-09
影响因子：
5.2
通讯作者：
J. Liang;L. Sushama
中科院分区：
文献类型：
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作者：
J. Liang;L. Sushama
大气河流（ARs）负责北美西部的危险水文气象事件。相对于1976-2005年，2070-2099年期间，区域气候模式模拟驱动的两个耦合的全球气候模式的RCP4.5和8.5的情景项目高达90%的增加AR发生在北美西部。结果还表明，AR相关冻雨（FR）事件的增加可能是由于与AR事件相关的动力和热力机制的变化。在加拿大西海岸，与AR相关的FR事件预计将加强，这是由与AR相关的差异涡度平流相关的中层上升增加所促进的。预计在美国西部内陆和加拿大西海岸，与AR相关的FR量的比例将增加，这可能是由于近地表冰点以下层和高空冰点以上层之间的温差增加。
Atmospheric rivers (ARs) are responsible for hazardous hydrometeorological events over western North America. For the period 2070–2099 relative to 1976–2005, regional climate model simulations driven by two coupled global climate models for the RCP4.5 and 8.5 scenarios project up to 90% increase in AR occurrences over western North America. Results also suggest that the increase in AR‐related freezing rain (FR) events is possibly due to changes in both dynamical and thermal mechanisms associated with AR events. In the west coast of Canada, AR‐related FR events are projected to intensify, which is facilitated by the increased midlevel ascent related to differential vorticity advection associated with ARs. The fraction of AR‐related FR amount is projected to increase over the inland of western U.S. and the west coast of Canada, which is possibly driven by the increased temperature difference between the subfreezing near‐surface layer and the above‐freezing layer aloft.