The Atlantic Meridional Overturning Circulation (AMOC) is an important element in the Earth’s Climate System, and it leads to variations in the climate systems, such as heat transformation, carbon dioxide distribution, freshwater distribution, and extreme weather conditions.
The dense water formation and export in the North Atlantic contribute to AMOC. Motivated by the aim to understand the strength and processes of AMOC in the Subpolar (SPNA), the water origins and transport routes are explored in this study, based on the inspiration of the previous studies of water pathways in the Labrador Sea.
The objective of this study is to investigate the origin of water in the Irminger Sea and the transport routes before arriving at Cape Farewell, the tip of Greenland where water continues to flow from the Irminger Sea to the Labrador Sea. Based on simulated field data in SPNA obtained from Modular Ocean Model (MOM), the Lagrangian method is applied in the Ocean Model Connectivity Modeling System (CMS), to track particles in the Irminger Sea. The properties of particles, such as location and temperature along their trajectory, are calculated at advection timesteps.
Origins of water reaching Cape Farewell through the Irminger Sea are discovered, including the source from the Denmark Strait, the Iceland-Scotland Ridge, and the South Iceland Basin. Water from these origins follows different routes before arriving at Cape Farewell and qualitative and quantitative analyses of these routes based on particle trajectories and particle numbers, provide insights into how water crosses the Irminger Sea and the importance of the routes.
In summary, water following the route from the Denmark Strait contributes 25 percent of the water through the Irminger Sea arriving at Cape Farewell. Water follows a direct and straight route along the East Greenland Boundary, as the cold source in the surface layer (50-150m). Water staying in the Irminger Basin contributes 50 percent. It travels in curved and blended routes in a deep layer (1200-1500m), as the warm source. Water from Iceland-Scotland Ridge follows a long-distance trajectory, which crosses the Iceland Basin, Reykjanes Ridges, and Irminger Basin. Water in this route contributes 20 percent. They travel in a surface layer as the warm source, while the temperature of water in this route decreases when water arrives at Cape Farewell. Water from the South Iceland Basin is in the surface layer (0-150m) along the routes, with the highest temperatures. The contribution is not accurate as the long-distance route requires a longer tracking period.
The research findings provide valuable insights into the dynamics of water masses in the Irminger Sea. It relates to the currents, and oceanic activities in the Irminger Sea, such as convention and eddies, which contributes to a better understanding of AMOC in SPNA.