He, Yunchang, Koszalka, Inga Monika , Sprecht, Mia S., Wekerle, Claudia, Schaffer, Janin and Kanzow, Torsten (2018) Pathways and fates of the warm Atlantic Intermediate Water toward 79NG Glacier Northeast Greenland. [Poster] In: AGU Fall Meeting 2018. , 10.-14.12.2018, Washington, D.C., USA .

Abstract

More than 25% of mean global sea level rise is caused by mass loss of Greenland Ice Sheet (GrIS). A significant part of this melt is attributed to the interaction between marine terminating glaciers of the GrIS and the surrounding warm ocean waters. Recent moored and ship-based observations suggest that Atlantic Intermediate Water (AIW) warmer than 1°C reaches the 79NG via the trough system on the East Greenland continental shelf, and that the southern route through the Norske Trough, is preferred. The origins and pathways of these warm AIW are elusive however due sparseness of observations from this remote and harsh environment.

Here we use a a high resolution FESOM (Finite Element Sea Ice-Ocean Model) and a suite of Lagrangian model and analysis tools to study the water pathways to the NEGIS and 79NG. We deploy 1915 Lagrangian particles at the Norske Trough and track them backwards to the Fram Strait and further, to the Atlantic and Arctic origins of these waters. The particle trajectories reveal that the warm water in the Trough is a mixture of three source waters: about 60% of particles crossed the northern section (80.64°N) towards the Arctic sea, about 20% crossed the Fram section (78.5°N) southward to the North Atlantic, and nearly 10% entered through an alternative route, the Westwind Trough. We calculate the travel time and water property changes of AIW along the trajectories. The released particles with temperature higher than 2°C reached Fram section after 200 days and colder water (1-2°C) take half this time (100 days). The interannual variability of particle crossings the Fram section has good agreement with the observed variability of AW temperature anomalies in Fram Strait at depth of 250m. Using Lagrangian statistics, we assess the role of the eddy mixing processes at the Fram Strait and that of the mesoscale recirculations in the Trough system.

Actions (login required)

View Item