Inter-annual Variability of the Current System off the West Greenland
Coast from a very high-resolution numerical model
Abstract
Analyzing a high-resolution (1/60°) numerical model over 2008 to 2018,
the inter-annual variability of the West Greenland Coastal Current
(WGCC) on the shelf and West Greenland Current (WGC) at shelf break is
presented. Both currents flow from Cape Farewell and extend to Davis
Strait, with their model speeds and transports corresponding well with
observations. The inter-annual variability of the WGCC and WGC near
southwest Greenland are opposite, with the former declining while the
latter strengthened, both by a speed change above 0.1 m/s. Both currents
are predominantly buoyancy forced, but wind forcing becomes more
dominant towards Davis Strait. The main exchanges from the two currents
to interior occur between Cape Desolation and Fylla Bank, with net
volume, freshwater, heat transport decreases of 1.4 Sv, 13 mSv, 36.7 TW.
The freshwater transport of the WGC itself does not drop in between
these sections, receiving freshwater from the WGCC to compensate for the
losses to the basin interior. Thus, we see significant freshwater (83.1
mSv) and heat transports (70.7 TW) of the WGC remaining at Fylla Bank
that reach the northern basin instead of being fluxed into the interior
pof the Labrador Sea. This suggests that the exchange between the
current system and the interior is more limited than previously thought,
and most of the Greenland and Arctic melt reaches the northern Labrador
Sea. Our results highlight the importance of resolving the WGCC and
shelf processes.