Water Vapor Transport and Near-Surface Salinity in the North Atlantic Ocean

July 31, 2018 08:45 AM
North Atlantic Atmospheric Moisture Transport.
© James Reagan

CICS-MD Scientist James Reagan (supporting NCEI) had a new article published on June 11 in the on-line journal Scientific Reports. He and co-authors from NCEI studied the subtropical-subpolar North Atlantic (NA) atmospheric moisture transport, which is an effective and rapid mechanism of freshwater transport between positive and negative Evaporation-Precipitation (E-P) regions in the North Atlantic.  The North Atlantic basin exhibits a large contrast in near-surface salinity, with high salinity (>37) in the subtropical region where E>P and low salinity (<35) in the subpolar region where P>E. A simplified schematic of this moisture transport is depicted in the figure.

In studying data from 1985–2012, the scientists found significant correlations between evaporation/high salinity in the subtropical region and precipitation/low salinity in the subpolar region.  These correlations suggest that there may be a relationship between water vapor production and divergence in the subtropics and its convergence and deposition in the subpolar region which ultimately impacts near-surface salinity.   This is a first step in being able to possibly utilize near-surface salinity as a proxy to estimate changes in the North Atlantic hydrological cycle. The ability to monitor and forecast the hydrological cycle is particularly important in the North Atlantic, where the salinity contrast is important in sustaining the Atlantic Meridional Overturning Circulation.

Reagan, James, Dan Seidov and Tim Boyer,2018: Water vapor transfer and near-surface salinity contrasts in the north Atlantic Ocean, Sci. Rep., 8, 8830,


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