2016/10/21 by Eleanor Frajka‐Williams, E. Frajka-Williams, Matthias Lankhorst +9
Earth and Planetary Sciences · Environmental Science · Physics and Astronomy · #Atmospheric and Oceanic Physics (physics.ao-ph) #Climate variability and models #FOS: Physical sciences #Geology and Paleoclimatology Research #Oceanographic and Atmospheric Processes #physics.ao-ph
paper · pdf · doi:10.48550/arxiv.1610.06708
arxiv created 2016/10/21 · openalex publication_date 2016/10/21 · arxiv updated 2016/10/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In situ boundary arrays have been installed in the North Atlantic to measure the large-scale ocean circulation. Here, we use measurements at the western edge of the North Atlantic at 16^∘N and 26^∘N to investigate low-frequency variations in deep densities and their associated influence on ocean transports. At both latitudes, deep waters (below 1100 dbar) at the western boundary are becoming fresher and less dense. The associated change in geopotential thickness is about 0.15 m2s-2 between 2004-2009 and 2010-2014, with the shift occurring between 2009-2010 and earlier at 26^∘N than 16^∘N. Without a similar density change on the east of the Atlantic, a mid-depth reduction in water density at the west drives an increase in the shear between the upper and lower layers of North Atlantic Deep Water of about 2.6 Sv at 26^∘N and 3.9 Sv at 16^∘N. While these transport anomalies result in an intensifying tendency in the meridional overturning circulation (MOC) estimate at 16^∘N, the method of applying a zero net mass transport constraint at 26^∘N results in an opposing (reducing) tendency of the MOC.