Australia: The Land Where Time Began

A biography of the Australian continent 

Tasman Sea Climate Change Projection from an Eddy-Resolving Ocean Model

The greatest rate of ocean warming in the 20^th century is displayed by the western boundary current regions of the ocean and it is projected by climate models that the accelerated rate of warming will continue as climate change progresses. According to Matear et al. all existing climate change projections come from simulations that do not fully resolve either these boundary currents or their eddies. In this paper Matear et al. show how the responses of the Tasman Sea to climate change differs from the projected changes obtained by the use of a coarse resolution Global Climate Model (GCM) by using of an Ocean Eddy-resolving Model (OEM) that captures the dynamics of the East Australian Current (EAC) as well as its eddies. The OEM projects that with climate change EAC transport is increased with eddy activity and there is a southwards latitudinal shift of approximately 1^o of the separation point of the EAC from the shelf after which it flows to the east. In the Tasman Sea the OEM increased the eddy activity with climate change, which then increases the nutrient supply to the upper levels of the ocean, and this then leads to an increase in concentrations of phytoplankton and a primary production increase of 10 % in the oligotrophic waters of the Tasman Sea. In the climate change projection of the GCM it projects there will be a decrease in primary production with climate change. When the OEM climate change projection for the Tasman Sea is applied to other western boundary current regions it suggests, according to Matear et al., the intensification of all western boundary currents with climate change should also increase eddy activity, which would then provide an important nutrient supply mechanism, and this should counter the increased stratification that is projected with global warming.

Sources & Further reading

1. Matear, R. J., M. A. Chamberlain, C. Sun and M. Feng (2013). "Climate change projection of the Tasman Sea from an Eddy-resolving Ocean Model." Journal of Geophysical Research: Oceans 118(6): 2961-2976.