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The representation of ocean circulation and variability in thermodynamic coordinates


Groeskamp, S and Zika, JD and McDougall, TJ and Sloyan, BM and Laliberte, F, The representation of ocean circulation and variability in thermodynamic coordinates, Journal of Physical Oceanography, 44, (7) pp. 1735-1750. ISSN 0022-3670 (2014) [Refereed Article]

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Copyright 2014 American Meteorological Society

DOI: doi:10.1175/JPO-D-13-0213.1


The ocean’s circulation is analyzed in Absolute Salinity SA and Conservative Temperature Θ coordinates. It is separated into 1) an advective component related to geographical displacements in the direction normal to SA and Θ isosurfaces and 2) into a local component, related to local changes in SA–Θ values, without a geographical displacement. In this decomposition, the sum of the advective and local components of the circulation is equivalent to the material derivative of SA and Θ. The sum is directly related to sources and sinks of salt and heat. The advective component is represented by the advective thermohaline streamfunction Ψadv SAΘ. After removing a trend, the local component can be represented by the local thermohaline streamfunction Ψloc SAΘ. Here, Ψloc SAΘ can be diagnosed using a monthly averaged time series of SA and Θ from an observational dataset. In addition, Ψadv SAΘ and Ψloc SAΘ are determined from a coupled climate model. The diathermohaline streamfunction Ψdia SAΘ is the sum of Ψadv SAΘ and Ψloc SAΘ and represents the nondivergent diathermohaline circulation in SA–Θ coordinates. The diathermohaline trend, resulting from the trend in the local changes of SA and Θ, quantifies the redistribution of the ocean’s volume in SA–Θ coordinates over time. It is argued that the diathermohaline streamfunction provides a powerful tool for the analysis of and comparison among ocean models and observation-based gridded climatologies.

Item Details

Item Type:Refereed Article
Keywords:circulation/ dynamics, atmosphere-ocean interaction, diffusion, mixing, ocean circulation, streamfunction, thermocline circulation
Research Division:Physical Sciences
Research Group:Other physical sciences
Research Field:Other physical sciences not elsewhere classified
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Measurement and assessment of marine water quality and condition
UTAS Author:Groeskamp, S (Mr Sjoerd Groeskamp)
ID Code:96114
Year Published:2014
Web of Science® Times Cited:30
Deposited By:IMAS Research and Education Centre
Deposited On:2014-10-20
Last Modified:2017-09-04

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