In Situ Measurements of Surface Winds, Waves, and Sea State in Polar Lows Over the North Atlantic
In Situ Measurements of Surface Winds, Waves, and Sea State in Polar Lows Over the North Atlantic
复制标题
北大西洋极地低气压表面风、波浪和海况的现场测量
DOI：
10.1029/2017jd028079
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
A. Carleton
中科院分区：
文献类型：
--
作者：
M. Rojo;C. Claud;G. Noer;A. Carleton
极地低(PL)风暴是中高纬度海域冬季次天气尺度大气环流的一个重要特征。它们可能会产生危险的条件，影响沿海和海洋活动，如捕鱼、运输和石油开采。然而，基于高分辨率海面数据的单个PL系统的研究很少。因此，利用挪威和北海8个观测站的现场测量，调查了1999-2013年14个冬季29个偏南环流的气象影响。平均而言，最大风速和有效波高(SWH)分别出现在气旋通过后1小时和3小时的最低海平面气压之后。最强风速平均为17.1m/S，最高峰值风速为6.3m，但分别可达31m/S和11m。系统水平范围、传播速度和大尺度大气环流环境的层内特征解释了层间差异较大的原因。在经向环流环境中，大的、多的和快速移动的PLS似乎比在纬向环流环境中的小的、单个的和缓慢移动的PLS产生更强的近地表风和更高的海浪。多个系统可能会产生最大的影响(例如，SWH>；8米)，尽管需要更大的样本量来确认这种可能性。PLS对海表面温度(SST)的影响很小，很难脱离背景SST变化来解释。观测到的海温下降可能主要是由于潜伏在其中的冷空气爆发引起的；事实上，在潜涡通过前的24小时内，发现了海温负异常，这表明低层大气不稳定增强。
Polar low (PL) storms are an important feature of the wintertime subsynoptic‐scale atmospheric circulation of middle‐ and higher‐latitude ocean areas. They can generate hazardous conditions impacting coastal and marine activities like fishing, transport, and oil extraction. However, there are few studies available of individual PL systems based on high‐resolution maritime surface data. Accordingly, the meteorological impacts of 29 PLs have been investigated for the 14 winters 1999–2013, using in situ measurements at eight stations in the Norwegian and North Seas. On average, the highest wind speed and significant wave height (SWH) occur following the minimum in sea level pressure of the PL, respectively, 1 and 3 hr after its passage. The strongest wind speed averages 17.1 m/s, and the highest peak SWH is 6.3 m, but these can reach 31 m/s and 11 m, respectively. PL characteristics of system horizontal extent, propagation speed, and the larger‐scale atmospheric circulation environment explain the large intercase differences. Large, multiple, and fast‐moving PLs within a meridional circulation environment appear to generate stronger near‐surface winds and higher waves than do small, single, and slow‐moving PLs within a zonal circulation. Multiple systems may have the largest impacts (e.g., SWH > 8 m), although a larger sample size is required to confirm this possibility. The impacts of PLs on sea surface temperature (SST) are quite small and are difficult to interpret separate from the background SST variation. The observed SST decrease may be mainly caused by the cold air outbreak within which the PL is embedded; indeed, a positive SST minus air temperature anomaly is found during the 24 hr preceding the passage of PL vortices, indicating enhanced low‐level atmospheric instability.