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A climatology of wintertime low-level jets in Nares Strait
Polar Research ( IF 1.9 ) Pub Date : 2021-04-19 , DOI: 10.33265/polar.v40.3622
Svenja H.E. Kohnemann , Günther Heinemann

Intense, southward low-level winds are common in Nares Strait, between Ellesmere Island and northern Greenland. The steep topography along Nares Strait leads to channelling effects, resulting in an along-strait flow. This research study presents a 30-year climatology of the flow regime from simulations of the COSMO-CLM climate model. The simulations are available for the winter periods (November–April) 1987/88 to 2016/17, and thus, cover a period long enough to give robust long-term characteristics of Nares Strait. The horizontal resolution of 15 km is high enough to represent the complex terrain and the meteorological conditions realistically. The 30-year climatology shows that LLJs associated with gap flows are a climatological feature of Nares Strait. The maximum of the mean 10-m wind speed is around 12 m s-1 and is located at the southern exit of Smith Sound. The wind speed is strongly related to the pressure gradient. Single events reach wind speeds of 40 m s-1 in the daily mean. The LLJs are associated with gap flows within the narrowest parts of the strait under stably stratified conditions, with the main LLJ occurring at 100–250 m height. With increasing mountain Froude number, the LLJ wind speed and height increase. The frequency of strong wind events (>20 m s-1 in the daily mean) for the 10 m wind shows a strong interannual variability with an average of 15 events per winter. Channelled winds have a strong impact on the formation of the North Water polynya.



中文翻译:

纳雷斯海峡冬季低空急流的气候学

在埃尔斯米尔岛和格陵兰北部之间的纳雷斯海峡,南风偏低。纳雷斯海峡沿岸陡峭的地形导致窜流效应,导致海峡两岸流动。这项研究通过对COSMO-CLM气候模型的模拟,提出了30年的流态气候学。该模拟适用于1987/88年至2016/17年冬季(11月至4月),因此覆盖的时间足以提供Nares Strait的长期特征。15 km的水平分辨率足够高,可以现实地表示复杂的地形和气象条件。30年的气候学表明,与间隙流相关的LLJ是Nares Strait的气候特征。平均10米风速的最大值约为12 ms -1 位于史密斯峡湾的南出口。风速与压力梯度密切相关。单个事件 的日平均风速达到40 ms -1。在稳定分层的条件下,低空急流与海峡最狭窄区域内的间隙流动有关,主要低空急流发生在100–250 m的高度。随着山弗洛德数的增加,LLJ风速和高度增加。 10 m风的强风事件的频率(每天平均> 20 ms -1)显示出强烈的年际变化,每个冬季平均15次。通道风对北水多面目的形成有很大的影响。

更新日期:2021-04-19
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