Abstract
Abstract. The Atlantic
Meridional Overturning Circulation (AMOC) is analyzed by applying a box
inverse model to hydrographic data from transatlantic sections along
14.5∘ N, occupied in 1989 and 2013, and along 24.5∘ N,
occupied in 1992 and 2015. Direct comparison of water mass properties among
the different realizations at the respective latitudes shows that the
Antarctic Intermediate Water (AAIW) became warmer and saltier at
14.5∘ N, and the densest Antarctic Bottom Water became lighter,
while the North Atlantic Deep Water freshened at both latitudes. The inverse
solution shows that the intermediate layer transport at 14.5∘ N was
also markedly weaker in 2013 than in 1989, indicating that the AAIW property
changes at this latitude may be related to changes in the circulation. The
inverse solution was validated using the RAPID and MOVE array data, and the
GECCO2 ocean state estimate. Comparison among these datasets indicates that
the AMOC has not significantly weakened over the past 2 decades at both
latitudes. Sensitivity tests of the inverse solution suggest that the
overturning structure and heat transport across the 14.5∘ N section
are sensitive to the Ekman transport, while freshwater transport is sensitive
to the transport-weighted salinity at the western boundary.
Funder
Deutsche Forschungsgemeinschaft
Subject
Cell Biology,Developmental Biology,Embryology,Anatomy
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