Polar lows over the Nordic and Labrador Seas: Synoptic circulation patterns and associations with North Atlantic‐Europe wintertime weather regimes
Polar lows over the Nordic and Labrador Seas: Synoptic circulation patterns and associations with North Atlantic‐Europe wintertime weather regimes
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北欧和拉布拉多海的极地低压：天气环流模式以及与北大西洋-欧洲冬季天气状况的关联
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
K. Kodera
中科院分区：
文献类型：
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作者：
P. Mallet;C. Claud;C. Cassou;G. Noer;K. Kodera
极地低压（Polar Lows，PL）是冬季在高纬度开放水域形成的强烈中尺度气旋。利用北大西洋PLs的几个数据集，天气环境有利于他们的发展确定。500 hPa位势高度、海表温度与500 hPa气温之差、近地面风和气温以及300 hPa位涡在以PL成因区为中心的大范围内呈现出显著的异常模式，表明冷空气爆发和平流层入侵。在挪威海的偏北气流、巴伦支海的东北气流和拉布拉多海的西风气流中，PLs发展。PL在一定的积累后形成，爆发日以强风和PV强化为标志。然后研究了PL与北大西洋-欧洲每日天气状况之间的关系。机制的典型寿命为8-10天，类似于与PL相关的大规模异常。在挪威和巴伦支海从1999年到2011年，37%的PL观察到在大西洋海岭制度（AR）和28%的负相制度的北大西洋涛动（NAO），而PL发生的概率减少了一半的正相NAO和斯堪的纳维亚阻塞（SB）制度。在拉布拉多海，大多数PL发生在NAO+期间，而在NAO−期间几乎不存在。基于更新的数据集展示关键因子的时间变化，并将PL与天气状况联系起来，将在PL预测方法中引入新的重要元素。
Polar Lows (PLs) are intense meso‐cyclones forming in winter at high latitudes over open water. Using several datasets of PLs over the North Atlantic, the synoptic environment conducive to their development is determined. The 500 hPa geopotential height, the difference between the sea surface temperature and the 500 hPa air temperature, the near‐surface wind and air temperature, and the 300 hPa potential vorticity present significant anomaly patterns over large areas centered over PL genesis zones, suggesting cold air outbreaks and stratospheric intrusions. PLs develop within a northerly flow in the Norwegian Sea, a northeasterly flow in the Barents Sea and a westerly flow in the Labrador Sea. PLs form after a certain build‐up, the outbreak day being marked by strong winds and PV intensification. The relationship between PLs and daily weather regimes over North Atlantic‐Europe is then investigated. Regimes have a typical lifetime of 8–10 days, similar to the large‐scale anomalies associated with PLs. Over the Norwegian and Barents seas from 1999 to 2011, 37% of PLs are observed during the Atlantic Ridge regime (AR) and 28% in the negative phase regime of the North Atlantic Oscillation (NAO), whereas PL probability of occurrence is reduced by half for the positive phase of NAO and the Scandinavian blocking (SB) regimes. Over the Labrador Sea, most PLs occur during NAO+ while they are almost absent during NAO−. Demonstrating the temporal variation of key factors based on an updated dataset and relating PLs to weather regimes will introduce novel and important elements in PL forecasting methodology.