Spatial Variations of Antarctic Intermediate Water in the Caribbean Sea Due To Vertical Mixing Along Its Path

Because of its pronounced fresh signature, the properties of the northward-flowing Antarctic Intermediate Water (AAIW) affect the Atlantic Meridional Overturning Circulation. Hence, understanding modifications of AAIW along its path is important. Here, we analyze AAIW changes along its path in the C...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: van der Boog, C.G. (author), Dijkstra, Henk A. (author), Pietrzak, J.D. (author), Katsman, C.A. (author)
Format: Article in Journal/Newspaper
Language:English
Published: 2022
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Online Access:http://resolver.tudelft.nl/uuid:6821983f-9aba-4d3d-9350-8025badea860
https://doi.org/10.1029/2021GL095977
Description
Summary:Because of its pronounced fresh signature, the properties of the northward-flowing Antarctic Intermediate Water (AAIW) affect the Atlantic Meridional Overturning Circulation. Hence, understanding modifications of AAIW along its path is important. Here, we analyze AAIW changes along its path in the Caribbean Sea and assess whether vertical fluxes from background turbulence and from double-diffusive mixing in thermohaline staircases can explain these variations. We deduce the occurrence rate of staircases (7%) and estimate the flux ratio (Formula presented.) from Argo float profiles. In combination with vertical fluxes from background turbulence, these values are used in a steady-state advection-diffusion model to estimate the effective diffusivity of salt that arises from double diffusion (Formula presented.). This value for (Formula presented.) is similar to observed values (Schmitt, 2005, https://doi.org/10.1126/science.1108678), implying the observed modification of AAIW in the Caribbean Sea may be attributable primarily to vertical mixing in the region itself. Environmental Fluid Mechanics