Composite wind pattern around the southern Greenland tip in CESM experiment to reveal subseasonal Atlantic Meridional Overturning variability

• Main Authors: Fedorov, A., de Jong, M., Wieners, C., Dijkstra, H.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Greenland; Irminger Sea; North Atlantic
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5020645

The Atlantic Meridional Overturning Circulation (AMOC) is the large-scale system of ocean currents that contributes to a moderate climate in northern Europe. AMOC transports vary on a range of time scales, from daily to centennial. Up to now, the role of atmospheric noise in subseasonal and intra-annual AMOC variations remains unclear. The current study describes a modeling experiment planned to reveal the importance of mesoscale winds around the southern tip of Greenland, named Tip Jets, in AMOC variability. Although Tip Jets are known to affect the heat content of the North Atlantic Subpolar Gyre intensifying deep water formation in the Irminger Sea, the open question is how this change in deep convection intensity evinces in the AMOC subseasonal variations. The experiment will be performed using the high-resolution (~10 km) Parallel Ocean Program (POP) model. Therefore, we constructed the composite Tip Jet forcings using daily ERA5 (25 km, December-March: DJFM, 1969-2022) momentum, and total surface heat fluxes, which will be added to the climatology to investigate the possible response of the AMOC system. Tip Jet events were defined as 10% strongest westerly winds in the region 59-60.5° N, 38-48° E. Forcings will be applied to the area outlined by the 30% contour of the greatest heat loss associated with Tip Jets. The described experiment is expected to disentangle the relative influence of momentum and heat Tip Jet forcing on the deep water formation and intra-annual AMOC variability.