Thermohaline staircases in the Caribbean Sea

Thermohaline staircases in the Caribbean Sea

Koetsier, Otto (TU Delft Civil Engineering & Geosciences; TU Delft Hydraulic Engineering; TU Delft Environmental Fluid Mechanics)

Katsman, C.A. (mentor)
Pietrzak, J.D. (graduation committee)
van der Boog, C.G. (graduation committee)
Dijkstra, Henk A. (graduation committee)
Maas, Leo R.M. (graduation committee)

Delft University of Technology
Universiteit Utrecht

2019-07-04

Thermohaline staircases are characterised by stepped vertical temperature, salinity and density profiles, which are formed and maintained by the double diffusion of heat and salt. Because double diffusion is the primary mixing agent in regions with staircases, it is the topic of extensive studies. Previous studies, however, are mainly theoretical and modelling orientated and observational evidence is needed to verify the results. In our study we use an extensive dataset with 460 vertical profiles of temperature and salinity. We found that staircases in the Caribbean Sea are related through temperature and salinity, indicating that
staircases in the Caribbean Sea are constant in time and space. Individual steps, however, differ and were characterised in four types: well-developed steps, transitional layers, inversions and absence of steps. A case study of a strong anticyclonic eddy gave the indication that steps are influenced by short term processes. The eddy induces lateral gradients and hereby positions the water masses in the interior and exterior of the eddy such that thermohaline
intrusions are initiated. The apparent preconditioning by the eddy, leading to thermohaline intrusions, allows us to speculate that the eddy is a catalyst in double diffusive diapycnal buoyancy transport.

double-diffusion
thermohaline staircases
Caribbean Sea
salt fingers

http://resolver.tudelft.nl/uuid:21edd195-8807-4cb7-9923-b62b12e137c2

2020-06-27

Student theses

master thesis

© 2019 Otto Koetsier