Details

Autor(en) / Beteiligte

• Bebieva, Yana
• Timmermans, Mary‐Louise

Titel

Double‐Diffusive Layering in the Canada Basin: An Explanation of Along‐Layer Temperature and Salinity Gradients

Ist Teil von

• Journal of geophysical research. Oceans, 2019-01, Vol.124 (1), p.723-735

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Double‐diffusive mixing gives rise to layered structures in the Arctic Ocean: layers within a double‐diffusive staircase overlying deeper layers associated with thermohaline intrusions. These layers exhibit well‐defined lateral temperature and salinity gradients. Gradients in salinity along individual layers change sign with depth, while along‐layer gradients in temperature remain the same sign with depth. A theoretical formalism is put forward to explain these features in terms of vertical divergences of double‐diffusive fluxes; temperature and salinity gradients along layers are set by the depth‐dependent ratio of double‐diffusive heat to salt fluxes. Examination of fine structure in temperature and salinity profiles reveals how the net flux ratio depends upon whether the layer is part of an evolving thermohaline intrusion or a staircase. The physical framework in context with observations of varying along‐layer gradients in temperature and salinity provides evidence for thermohaline intrusions evolving to a staircase and describes the parameters that dictate this process. Results bring new understanding to heat and salt transport in the Arctic Ocean as well as the physics of double‐diffusive layering in the world's oceans. Plain Language Summary A type of ocean mixing process, double‐diffusive convection, gives rise to layers in the Arctic Ocean that may be characterized by their differing temperature and salinity properties. The properties and physics of these layers are key to understanding how heat is transported vertically and laterally in the Arctic Ocean. A theoretical formalism is put forward to explain distinct features of the layers that are characterized in the observations. The physical framework in context with observations brings new understanding to how the layers evolve and how they relate to heat and salt transport in the Arctic Ocean. Key Points Arctic double‐diffusive staircases and intrusions have along‐layer temperature/salinity gradients that arise from vertical flux divergences The transition in depth between staircases and intrusions depends on basin‐scale lateral temperature gradients and stratification strength The magnitude of lateral Atlantic Layer heat and salt transport depends on vertical stratification and distance from the boundary current