Continuous Estimate of Atlantic Oceanic Freshwater Flux at 26.5°N

Abstract

The first continuous estimates of freshwater flux across 26.5°N are calculated using observations from the RAPID/MOCHA/WBTS array and Argo floats every ten days between April 2004 and October 2012. The freshwater flux (FW) is -1.17 ± 0.20 Sv (1 Sv = 106 m3 s-1; mean ± standard deviation; negative flux is southward), implying a freshwater divergence of -0.37 ± 0.20 Sv between Bering Strait and 26.5°N. This is in the sense of an input of 0.37 Sv of freshwater to the ocean, consistent with a region where precipitation dominates over evaporation. The sign and the variability of the freshwater divergence are dominated by the overturning component (-0.78 ± 0.21 Sv). The horizontal component of the freshwater divergence is smaller, associated with little variability and positive (0.35 Sv ± 0.04 Sv). A linear relationship, describing 91% of the variance, exists between the strength of the meridional overturning circulation (MOC) and the freshwater flux (-0.37 Sv - 0.047Sv of FW per Sv of MOC). The time se...