Abstract
We present year-round estimates of liquid freshwater transport (FWT) in
the East Greenland Current (EGC) in the western Fram Strait from mooring
observations since 2015. Novel data from additional instruments deployed
in recent years are used to correct earlier estimates when instrument
coverage was lower. The updated FWT time series (reference salinity
34.9) show that the increased export between 2010 and 2015 has not
continued, and that FWT has decreased to pre-2009 levels. Salt transport
independent of a reference salinity is shown not to be sensitive to
salinity changes. Between 2015-2019, the FWT in the Polar Water
decreased to an average of 56.9 (±4.5) mSV, 15% less than the 2003-2019
long-term mean, however, high FWT events occurred in 2017. The overall
decrease is related with a slowdown of the EGC, partly attributed to a
decrease of the baroclinic component, due to salinification of the
halocline waters (26.5 < σθ < 27.7 kg/m3) which
counterbalanced the freshening of the surface layer (σθ < 26.5
kg/m3). Our results show changes in the Polar Water between 2003-2019:
Salinity stratification increased as the salinity difference between 155
and 55 m increased by 0.63 psu , the Polar Water layer became thinner by
46 m and the Polar-Atlantic front moved abruptly west in June 2015. All
processes point to an “Atlantification” of the western Fram Strait and
reduced Polar outflow. Including the novel data sets decreased the
uncertainty of the FWT to an average of 8% after 2015, as opposed to
17% in earlier estimates.