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

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

van der Boog, C.G. (TU Delft Environmental Fluid Mechanics; California Institute of Technology)
Dijkstra, Henk A. (Universiteit Utrecht)
Pietrzak, J.D. (TU Delft Environmental Fluid Mechanics)
Katsman, C.A. (TU Delft Environmental Fluid Mechanics)

2022

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.

background turbulence
double diffusion
vertical mixing
water mass

http://resolver.tudelft.nl/uuid:6821983f-9aba-4d3d-9350-8025badea860

https://doi.org/10.1029/2021GL095977

2022-08-09

0094-8276

Geophysical Research Letters, 49 (3)

Institutional Repository

journal article

© 2022 C.G. van der Boog, Henk A. Dijkstra, J.D. Pietrzak, C.A. Katsman