Mechanisms governing the inter-annual variability of water properties on the south-east Greenland continental shelf.

Federica Facchinetti1,2, Fiammetta Straneo3, Doroteaciro Iovino4, James Holte3, Isabela Alexander-Astiz Le Bras3 and Simona Masina5, (1)Euro-Mediterranean Center on Climate Change, Bologna, Italy, (2)Ca' Foscari University, Venice, Italy, (3)Scripps Institution of Oceanography, La Jolla, CA, United States, (4)Euro-Mediterranean Center on Climate Change, Ocean Modeling and Data Assimilation Division, Bologna, Italy, (5)Euro-Mediterranean Center on Climate Change, Ocean Modelling and Data Assimilation, Bologna, Italy
Abstract:
Greenland glacial fjords link the ice sheet and the large-scale ocean through the import of oceanic
heat and the export of melt-water. There is widespread consensus that a portion of the recent
Greenland mass loss was triggered by increased submarine melting at the glacier/ocean interface
located at the heads of Greenland’s fjords. As the properties inside glacial fjords are set by those on
the adjacent shelves, understanding the mechanisms that govern the variability of water mass
properties on the shelf of Greenland is an important part of understanding the stability of the
Greenland ice sheet.
In southeast (SE) Greenland there are two main water masses: Polar Water (PW) from the Arctic
Ocean, and Atlantic Water (AW) from the Irminger Sea. Due to the lack of observations in this
region, the relative partitioning of these water masses, their interaction, and seasonal to inter-annual
variability are poorly understood.
The study presented here makes use of a high-resolution eddy resolving global model (with
horizontal resolution of ~ 4 km on the SE Greenland shelf), based on NEMO ocean model, to
investigate the inter-annual variability of the currents, heat-content and freshwater transport on the
shelf and identify their potential drivers of this variability in the period 2008-2017.
The model compares favorably with a range of observations in the region. We find that the water
mass variability on the outer shelf matches that in the Irminger Sea, while changes on the inner
shelf are de-coupled and have an upstream source. We show that inter-annual changes are due to
combination of changes in atmospheric forcing, subpolar-gyre circulation and changes in the
transport of the East Greenland Current system.