Open AccessAnalysis of hydrographic and stable isotope data to determine water masses, circulation, and mixing in the eastern Great Australian Bight
Author(s) -
Richardson Laura E.,
Kyser T. Kurt,
James Noel P.,
Bone Yvonne
Publication year - 2009
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jc005407
Subject(s) - hydrography , water mass , ocean gyre , oceanography , upwelling , plume , circumpolar deep water , geology , current (fluid) , salinity , boundary current , temperature salinity diagrams , water column , surface water , bottom water , continental shelf , ocean current , subtropics , environmental science , north atlantic deep water , thermohaline circulation , geography , environmental engineering , fishery , meteorology , biology
Hydrographic and stable isotope data from waters in the eastern Great Australian Bight (GAB) sampled during March–April 1998 indicate that both mixing and evaporative processes are important on the shelf. Five water masses are defined on the basis of their temperature, salinity, δ 2 H and δ 18 O values. Two of these are end‐members, the Flinders Current (FC) and the Great Australian Bight Plume (GABP), whereas the other three are a result of mixing between these two end‐members. Water mass distribution reflects an anticyclonic gyre in the eastern GAB. Cool and fresh water present at depth along the Eyre Peninsula is sourced from upwelling of Flinders Current water directly from the shelf break. This water is progressively heated, evaporated, and mixed with warmer and more saline shelf waters as it flows around the gyre. High temperatures, salinities, and δ 2 H values in surface waters in the central GAB suggest that the Great Australian Bight Plume has a greater spatial extent than previously recorded, also occurring along the shelf edge between 130°E and 133°E. A high temperature, high salinity, low δ 2 H water mass that is isotopically similar to the Flinders Current occurs in the west of the study area, indicating intrusion of Flinders Current water into the central GAB. Differences in isotopic compositions of off‐shelf water suggest that the Great Australian Bight Plume is flowing off the shelf and mixing with Flinders Current water at ∼132°E; however, this outflow does not generate an eastward flowing current during the period when samples were collected.