Interactions and Feedbacks along Pathways of the Glacier Melt Water
Recent studies using climate models and paleocenographic records point to far-reaching impacts of fresh water flux from the melting Greenland Ice Sheet (GrIS) on the subpolar Atlantic Ocean circulation, convection and overturning, the European climate and the sea level fingerprint in different regions of the World Ocean. Relatively little is known however about its impacts on ocean circulation around Greenland. In particular, interaction (mixing) of the glacier melt water with warmer water masses on the Greenland continental shelf may lead to a nonlocal negative feedback on the ocean heat flux toward marine-terminating glaciers and thus on their basal melt rates. The glacier meltwater pathways on the continental shelf, mixing, and feedbacks are not well understood as neither modeling studies focused on large-scale impacts of the GrIS melt nor the sparse observations resolve the circulation around the Greenland adequately.
Subproject 11 considers the ocean circulation around Greenland and its changes due to increased glacier melt, interaction of melt water with the ambient ocean, and the feedbacks on the melting processes. We perform simulations of large numbers of Lagrangian particles representing water masses and allowing astatistical description of model water properties (temperature, salinity) along particle trajectories and of mixing processes. Lagrangian trajectories have an interpretative quality by connecting changes in velocity or water properties at different locations.
Our Lagrangian framework will be embedded in model simulations of subproject 9 (General Estuarine Transport Model, targeting ocean circulation close to the 79NG) and in the FESOM (Finite Element Sea Ice-Ocean Model) high resolution simulations performed by subproject 10. We also collaborate tightly with other subprojects regarding the setup of our model experiments, comparison with observations and interpretation of the results. The long-term vision is to develop, together with our GROCE partners, a modeling-analysis framework that could be applied in other regions of Greenland and Antarctica and lead to future improvement of prediction of the glacier melt and its impacts.