Extreme warm events in the South Orkney Islands, Southern Ocean: Compounding influence of atmospheric rivers and föhn conditions
Extreme warm events in the South Orkney Islands, Southern Ocean: Compounding influence of atmospheric rivers and föhn conditions
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南大洋南奥克尼群岛的极端温暖事件：大气河流和焚风条件的复合影响
DOI：
10.1002/qj.4578
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发表时间：
2023
影响因子：
8.9
通讯作者：
Lu H
中科院分区：
文献类型：
--
作者：
Lu H
利用Signy站和Orcadas站1947-1994年和1956-2019年的天气观测资料，研究了南奥克尼群岛（SOIs）的极端暖事件。将极端温度定义为超过温度分布第95百分位的温度，我们揭示了温暖事件的特征和相关驱动因素，特别是夏季和冬季的前10个事件。在这两个站点，极端温暖事件通常涉及大气河流（AR）和局部焚风变暖的综合影响，由于站点相对于加冕岛（SOI中最大和最高的岛屿）的位置而具有独特的特征。例如，西尼的暖事件比奥尔卡达斯相应的同期温度要高（平均约3°C）。在这两个观测站，每年温暖事件的数量在有记录的时期内显著增加，这可能会通过增加冰雪融化来影响生态系统。西尼的极端温暖事件主要是由焚风变暖和来自南大西洋的AR所主导，在那里，温暖，富含水分的空气被增强的北风迅速平流到岛屿。相比之下，Orcadas的极端温暖包括暖空气平流和föhn变暖，与增强的西北风/西风带有关，其中AR起源于太平洋，穿过德雷克海峡。使用英国气象局大气统一模式的1 km网格间距配置模拟Signy站的前10大暖事件之一，以解开局部与大尺度强迫的作用。我们发现，大部分的变暖可以归因于弗恩效应的案例研究。这些结果表明了南极极端温度的复杂性。
Extreme warm events in the South Orkney Islands (SOIs) are investigated using synoptic observations from Signy and Orcadas stations for 1947–1994 and 1956–2019 respectively. Defining the extremes as temperatures exceeding the 95th percentile of the temperature distribution, we reveal the characteristics and associated drivers of the warm events, especially the top 10 events in both summer and winter. At both stations, extreme warm events often involve a combined effect of atmospheric rivers (ARs) and localised föhn warming, with distinct characteristics due to the station locations relative to Coronation Island, the largest and highest island of the SOIs. For example, warm events at Signy are warmer (by an average of around 3°C) than the corresponding concurrent temperatures at Orcadas. The number of warm events per year has significantly increased over the record periods at both stations, which could potentially impact ecosystems by increasing melting of snow and ice. Extreme warm events at Signy are dominated by föhn warming in combination with ARs originating from the Southern Atlantic Ocean, where warm, moisture‐rich air is rapidly advected towards the islands by enhanced northerly winds. By contrast, the Orcadas warm extremes involve both warm‐air advection and föhn warming associated with enhanced northwesterlies/westerlies with ARs originating in the Pacific Ocean that travel across the Drake Passage. Simulation of one of the top 10 warm events for Signy station using a 1‐km grid spacing configuration of the atmosphere‐only UK Met Office Unified Model is used to disentangle the role of local versus large‐scale forcing. We find that the majority of the warming can be attributed to föhn effects for the case study. These results demonstrate the complexity of Antarctic temperature extremes.
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DOI：
10.1002/joc.965
发表时间：
2004-01
期刊：
International Journal of Climatology
影响因子：
--
作者：
J. Turner
通讯作者：
J. Turner
DOI：
10.1002/joc.6366
发表时间：
2020-04
期刊：
International Journal of Climatology
影响因子：
--
作者：
D. Bannister;J. King
通讯作者：
D. Bannister;J. King
DOI：
10.1080/10962247.2021.1942319
发表时间：
2021-06
影响因子：
2.7
作者：
W. Robinson
通讯作者：
W. Robinson
影响因子：
8.9
作者：
E. Gilbert;Andrew Orr;John C. King;I. Renfrew;T. Lachlan-Cope;P. Field;I. Boutle
通讯作者：
E. Gilbert;Andrew Orr;John C. King;I. Renfrew;T. Lachlan-Cope;P. Field;I. Boutle
南半球新的第 3 波纬向波指数
影响因子：
4.9
作者：
R. Goyal;M. Jucker;Alexander Sen Gupta;M. England
通讯作者：
M. England