Assessing the Southern Ocean in a warming world and its influence on New Zealand’s climate

  • Project Duration: 2015-2019
  • Project funding: $1m

Changes in ocean heat content dominate the global energy budget, accounting for 93% of the global energy change since the 1970s. The exchange of heat between the atmosphere and ocean, and storage of heat within the ocean, create intrinsic climate variability that presents challenges for climate simulations, particularly for decadal and multi-decadal projections.

Improved simulations of these ocean processes are required to better represent the ocean temperatures necessary for projections of New Zealand climate. Changes in Southern Ocean temperatures influence weather systems reaching New Zealand by altering the position of the Southern Hemisphere storm track and cyclone development. Decadal ocean-atmosphere interactions also directly impact New Zealand’s climate.

This project addresses the ocean’s role in climate simulations through interconnected tasks that analyse new observations, develop new numerical ocean modelling capability, and evaluate ocean heat transport and storage in the NZESM. The first part of the project will analyse changes in the Southern Ocean heat content and heat transport and the processes driving these changes using observations and reanalysis of existing oceanographic data. The results will be compared to existing climate simulations and the high-resolution ocean simulations (in the second part) to identify the processes that are a priority for improving the model.

The second part of the project will validate the behaviour of the ocean model component in the NZESM, both globally and in the New Zealand region and focus on reducing biases in the model that are specific to the Deep South region.

Primary Contact and Principle Investigator:

  • Dr. Melissa Bowen, University of Auckland,

Melissa is a physical oceanographer who studies the physical state of the ocean (currents, temperatures, salinities) and the reasons why the ocean varies. Much of her research uses satellite observations combined with in situ observations and comparisons to mechanistic models. More information on Melissa’s work can be found here.

Project partners:

  • University of Auckland
  • NIWA
  • Scripps Institute of Oceanography (USA)
  • GEOMAR (Germany)
  • UK Met Office
  • University of New South Wales (Australia)

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