Controls on upper ocean salinity variability in the eastern subpolar
North Atlantic during 1992-2017
- Ali Hasan Siddiqui,
- Thomas W N Haine,
- An T Nguyen,
- Martha Weaver Buckley
Abstract
The eastern subpolar North Atlantic upper ocean salinity undergoes
decadal fluctuations. A large fresh anomaly event occurred during
2012--2016. Using the ECCO state estimate, we diagnose and compare
mechanisms of this low salinity event with that of the 1990s fresh
anomaly event. To avoid erroneous interpretations of physical mechanisms
due to reference salinity values in the freshwater budget, we perform a
salt mass content budget analysis of the eastern subpolar North
Atlantic. It shows that the recent fresh anomaly occurs due to the
circulation of anomalous salinity by mean currents entering the eastern
subpolar basin from its western boundary via the North Atlantic Current.
This is in contrast to the early 1990s, when the dominant mechanism
governing the fresh anomaly was the transport of the mean salinity field
by anomalous currents across the southern boundary of the subpolar North
Atlantic.13 Jan 2024Submitted to ESS Open Archive 15 Jan 2024Published in ESS Open Archive