Vortices in the Subarctic Seas and their interactions with bottom topography

Abstract

Coherent swirling bodies of water; mesoscale (10-100 km) vortices, are an essential part of the general ocean circulation. Mesoscale vortices are abundant everywhere in the World Ocean and are vital in upholding equilibrium balances that govern the global circulation and thus also the climate. In order to obtain a better understanding of the general circulation in the global ocean, there is a need of more insight into vortex life cycles and impacts, such as their formation, spatial structure, distribution, and interactions with neighboring vortices and with the ambient environment. Gaining more knowledge of the mesoscale vortex field is not only crucial for our present-day understanding of the circulation, but also for future predictions of climate. Studying the mesoscale vortex field is challenging in the polar regions since vortex length scales significantly decrease with latitude. The small length scales make them both harder to observe and to model. In this thesis, simplified theory and idealized and realistic high-resolution modeling is combined to gain insight the mesoscale vortex field in a climate-sensitive high latitude region, namely the Subarctic Seas. A unique, long-lived high pressure system situated in the Lofoten Basin is specifically examined. How this storm has kept intact for perhaps over 100 years has been puzzling, and this thesis shows a direct link to the process responsible for its regeneration.