Abstract

In this study we explore the origin of the high stability of the Lofoten vortex, persistently observed in the central part of the Lofoten Basin of the Norwegian Sea. It is shown that the higher steepness of the southwestern bottom slopes and a small inclination of the bottom topography towards the region where the Norwegian Current splits into two branches increase the dynamic stability of the Lofoten vortex. The observed minor variations of bottom topography of the basin form the area with the small gradients of the background potential vorticity. When residing in this area, the Lofoten vortex can retain 60 to 90% of the core volume over two years, even without gaining energy from external sources. When the vortex deviates from its mean position in the center of the basin, or when the external conditions deviate from their characteristic values for the Lofoten basin, the rate of the Lofoten vortex deformation and decay typically increases. Thus, the topography of the Lofoten Basin together with the characteristics of the Norwegian Current in the study region form almost optimal conditions for the permanence of an anticyclonic vortex in the center of the basin.

中文翻译：

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挪威海罗弗敦涡旋稳定性研究

摘要

在这项研究中，我们探索了在挪威海罗弗敦盆地中部持续观察到的罗弗敦涡旋的高稳定性的起源。结果表明，西南底坡陡度较高，底面地形向挪威洋流分叉两支地区的小倾斜，增加了罗弗敦涡旋的动力稳定性。观察到的盆地底部地形的微小变化形成了背景位涡梯度很小的区域。当驻留在该区域时，即使不从外部来源获取能量，罗弗敦涡旋也可以在两年内保留核心体积的 60% 至 90%。当涡流偏离其在盆地中心的平均位置时，或者当外部条件偏离罗弗敦盆地的特征值时，罗弗敦涡旋变形和衰减的速率通常会增加。因此，罗弗敦盆地的地形与研究区域内挪威洋流的特征共同构成了盆地中心反气旋涡旋持续存在的最佳条件。